1.1 Circuit Studies Research Content
The field of circuit studies typically focuses on three primary areas of research:
Circuit Analysis
Given the structure and parameters of a circuit, find the circuit responses ($u$, $i$, $\dots$).
Circuit Synthesis
Given the circuit responses/behavior, determine the structure and parameters of the circuit (the solution may not be unique).
Circuit Design
From several alternative candidate schemes that satisfy performance requirements, select and determine the final circuit structure and parameters based on constraints such as cost, volume, and reliability.
1.2 Current and Voltage Definition
The fundamental variables in electric circuits are defined as follows:
- Current: $$i = \frac{dq}{dt}$$
- Voltage: $$u_{AB} = \frac{dw_{AB}}{dq} = \varphi_A - \varphi_B$$
1.3 Reference Directions and Power
Reference directions are critical for defining the algebraic sign of circuit variables. We analyze power using two configurations:
Associated Reference Direction
The reference direction of current $i$ enters the terminal designated with positive voltage polarity ($+$).
Power: $p(t) = u(t)i(t)$
Non-associated Reference Direction
The reference direction of current $i$ leaves the terminal designated with positive voltage polarity ($+$).
Power: $p(t) = -u(t)i(t)$
Power Calculation Rules (Under the Associated Reference Direction):
- If calculated power is positive ($P_{\text{abs}} > 0$), the circuit element absorbs power.
- If calculated power is negative ($P_{\text{del}} < 0$), the circuit element delivers (generates) power.
1.4 Modeling of Circuit Elements
Circuit modeling involves establishing relationships between fundamental variables ($u$, $i$, $\psi$, $q$). For linear elements, these relationships simplify to the following classical formulations:
Resistance: relation between voltage and current
$$u = f(i) \xrightarrow{\text{Linear}} u = R i$$
Inductance: relation between magnetic flux linkage and current
$$\psi = f(i) \xrightarrow{\text{Linear}} \psi = L i \implies u_L = L \frac{di}{dt}$$
Capacitance: relation between charge and voltage
$$q = f(u) \xrightarrow{\text{Linear}} q = C u \implies i_C = C \frac{du}{dt}$$
1.5 Fundamental Perspectives in Circuit Analysis
When analyzing circuit problems, three fundamental perspectives are employed:
-
Abstract Perspective: Mapping from a physical system to field representations, and finally to idealized circuit models:
Physical Model $\rightarrow$ Electromagnetic Field Model $\rightarrow$ Circuit Model
-
Engineering Approximation Perspective: Approximating non-linear and complex physical components with simplified behavioral models (e.g., operational amplifiers, diodes, transformers).
-
Equivalence Perspective: Determining equivalence for one-port networks. For instance, if two networks have terminal relationships $u = f_1(i)$ and $u = f_2(i)$ respectively, their electrical equivalence implies:
$$f_1 = f_2$$
Page 4
The average value: $$\overline{x} = \frac{1}{T} \int_{0}^{T} x(t) dt$$
The effective value: $$\overline{y} = \sqrt{\frac{1}{T} \int_{0}^{T} y(t)^2 dt}$$
The RMS voltage of a sine wave is given by: $$U = \sqrt{\frac{1}{T} \int_{0}^{T} u(t)^2 dt}$$
For a sine wave voltage: $$u(t) = U_m \sin(\omega t - \phi)$$
The RMS voltage is: $$U = \frac{U_m}{\sqrt{2}}$$
Linear circuit: $$ay_1 + by_2 = f(ax_1 + bx_2)$$
Passive circuit: $$\int_{-\infty}^{t} u(\tau) v(\tau) d\tau \geq 0$$
Active circuit: $$\int_{-\infty}^{t} u(\tau) v(\tau) d\tau < 0$$
Total parameter circuit: The current and voltage of the component are not functions of the component's spatial dimensions. The component model is an indivisible whole.
Distributed parameter circuit: The current and voltage along the transmission line are functions of the spatial dimension. This is used when the spatial dimensions of the component and the wavelength of the electromagnetic wave are comparable.
Another case is when considering leakage current. For example, in a distributed parameter model: parallel resistance (inter-wire energy leakage) → parallel capacitance (inter-wire electric field) → inductance (magnetic field) → resistance (loss).
Page 5
**Kirchhoff's Laws**
1. **Current:**
$$ di = \frac{dq}{dt} = \frac{en\vec{v} \cdot d\vec{s}}{dt} = en\vec{v} \cdot d\vec{s} $$
$$ \vec{J} = en\vec{v} \quad \therefore i = \iint \vec{J} \cdot d\vec{s} $$
2. **Voltage:**
$$ \varphi_A - \varphi_B = \frac{dU_{AB}}{dt} = \frac{1}{\partial q} \int_A^B \vec{F} \cdot d\vec{r} = \frac{1}{\partial q} \int_A^B dq \vec{E} \cdot d\vec{r} = \int_A^B \vec{E} \cdot d\vec{r} = U_{AB} $$
3. **Power:**
$$ \vec{F} = dq \cdot \vec{E} \quad dw = Fvdt = dq \cdot E \cdot v \cdot dt $$
$$ P = \frac{dw}{dt} = dq \cdot E \cdot v = \frac{dq}{dt} \cdot E \cdot v \cdot dt = i(t) \cdot u(t) $$
In non-associated reference direction, $$ P(t) = -i(t) \cdot u(t) $$
4. **KCL:**
$$ \oint \vec{J} \cdot d\vec{s} = \frac{dq_{net}}{dt} = 0 \quad \text{or} \quad \sum i = 0, \text{or} \quad \sum_{in} i = \sum_{out} i $$
5. **KVL:**
$$ \oint \vec{E} \cdot d\vec{r} = 0, \quad U_{AB} = \int_A^B \vec{E} \cdot d\vec{r} \quad \text{or} \quad \sum u = 0, \text{or} \quad \sum_{down} u = \sum_{up} u $$
**Independent Sources:**
- Voltage Source: The voltage at the terminals of the voltage source or the current flowing through the element of the voltage source is determined solely by its internal characteristics and is independent of the external circuit or connected elements. Examples: Battery, microphone.
- Current Source: The current flowing through the terminals of the current source or the current flowing through the element of the current source is determined solely by its internal characteristics and is independent of the external circuit or connected elements. Examples: Solar cell.
**Controlled Sources:**
- VCVS, VCCS, CCVS, CCCS (the second C stands for controlled)
- There are two parts: the control terminal and the output terminal. Therefore, a two-terminal network can be described as follows:
- $$ u_1 = g_{m} i_1 $$
- $$ u_2 = g_{m} i_2 $$
- $$ g_m: \text{transconductance} $$
- $$ r_m: \text{transresistance} $$
- $$ \beta: \text{transconductance ratio} $$
Page 6
1. **Resistance Equivalent Transformation**
A two-terminal network without independent sources can be replaced by an equivalent resistance, \( R_{eq} = \frac{U}{I} \).
**① Series Resistors**
From \( U = U_1 + ... + U_n \), \( U_k = R_k i \) we get:
$$ U = (R_1 + ... + R_n) i $$
Therefore, \( R_{eq} = \frac{U}{I} = R_1 + ... + R_n \).
**② Parallel Resistors**
From \( i = i_1 + ... + i_n \), \( i_k = \frac{U_k}{R_k} = \frac{U}{R_k} \) we get:
$$ i = (\frac{1}{R_1} + ... + \frac{1}{R_n}) U $$
Therefore, \( R_{eq} = \frac{U}{I} = (\frac{1}{R_1} + ... + \frac{1}{R_n})^{-1} \), i.e., \( G_{eq} = G_1 + ... + G_n \).
**③ Balanced Bridge**
**④ Y-Δ Equivalent Transformation**
[DIAGRAM 2]
In Δ form:
$$ i_1 = \frac{U_{12}}{R_{12}} - \frac{U_{21}}{R_{21}} $$
$$ i_2 = \frac{U_{23}}{R_{23}} - \frac{U_{12}}{R_{12}} $$
$$ i_3 = \frac{U_{31}}{R_{31}} - \frac{U_{23}}{R_{23}} $$
In Y form:
$$ U_{12} = R_1 i_1 - R_2 i_2 $$
$$ U_{23} = R_2 i_2 - R_3 i_3 $$
$$ U_{31} = R_3 i_3 - R_1 i_1 $$
$$ i_1 + i_2 + i_3 = 0 $$
$$ U_{12} + U_{23} + U_{31} = 0 $$
Page 7
In $\Delta$ form, we have:
$$ u_{12} = \frac{R_{12} R_{31} i_1 - R_{31} R_{12} i_2}{R_{12} + R_{23} + R_{31}} $$
$$ u_{23} = \frac{R_{23} R_{12} i_2 - R_{31} R_{23} i_3}{R_{12} + R_{23} + R_{31}} $$
$$ u_{31} = \frac{R_{31} R_{23} i_3 - R_{12} R_{31} i_1}{R_{12} + R_{23} + R_{31}} $$
Comparing with the Y form, we get:
$$ R_{1} = \frac{R_{12} R_{31}}{R_{12} + R_{23} + R_{31}} $$
$$ R_{2} = \frac{R_{23} R_{12}}{R_{12} + R_{23} + R_{31}} $$
$$ R_{3} = \frac{R_{31} R_{23}}{R_{12} + R_{23} + R_{31}} $$
$$ R_{12} = R_1 + R_2 + \frac{R_1 R_2}{R_3} $$
$$ R_{23} = R_2 + R_3 + \frac{R_2 R_3}{R_1} $$
$$ R_{31} = R_3 + R_1 + \frac{R_3 R_1}{R_2} $$
5. Equivalent resistance of a two-terminal network with resistors and controlled sources.
For such a network, if the controlled source is in the network, it can be equivalent to a resistor. (The terminal voltage-current relationship is the same). Using current or voltage to find the terminal voltage and current in a linear relationship can find the equivalent resistance.
3. Power supply equivalent transformation.
1. Ideal independent voltage source in series (voltage source)
$$ u_{eq} = u_{s1} + \ldots + u_{sn} $$
2. Ideal independent current source in parallel (current source)
$$ i_{eq} = i_{s1} + \ldots + i_{sn} $$
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4. Metal-Oxide-Semiconductor-Field-Effect-Transistor
Applications:
- Digital systems: logic gates.
- Analog systems: amplifiers.
Model: Three-terminal device, such as N-channel enhancement-type MOSFET:
- G: Gate (always open)
- S: Source
- D: Drain
Electrical characteristics: Ugs affects the I-V characteristics between D and S.
1) When 0 ≤ Ugs ≤ U_T, D-S is open.
2) When Ugs > U_T, Uds < Ugs - U_T, then the switch closes. D-S appears as a resistor, known as the MOSFET switch-resistor model.
3) When Ugs > U_T, Uds > Ugs - U_T, then the switch closes. D-S appears as a voltage-controlled current source, id = K(Ugs - U_T)^2, known as the switch-current-source model.
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No.
Date.
$$\begin{array}{c|c}
U_{DS}/V & I_{DS}/A \\
\hline
0 & 0 \\
2V & \frac{K}{2} \\
3V & 2 \\
\end{array}$$
$$U_{GS}=3V$$
$$U_{GS}=2V$$
$$U_{GS}=0V$$
$$U_{DS}/V$$
When \(U_{GS}=U_{IN}\), when \(0 < U_{IN} < U_{T}\), ① \(I_{DS}=0\), D-S does not conduct.
When \(U_{GS}=U_{IN}\) and \(U_{IN}=0\), \(I_{DS}=0\), D-S does not conduct.
When \(U_{IN} > U_{T}\), when \(U_{IN} > 0\), ② then \(U_{DS} < U_{IN}\) when D-S is a resistor.
Resistance is \(R_{DS} = \frac{U_{DS}}{I_{DS}} = \frac{U_{IN} - U_{T}}{\frac{K}{2}(U_{IN} - U_{T})^2} = \frac{2}{K(U_{IN} - U_{T})} = \frac{2}{K} \cdot \frac{1}{U_{IN} - U_{T}}\)
③ When \(U_{DS} > U_{IN}\), D-S is a voltage-controlled current source.
$$I_{DS} = \frac{K}{2} \cdot (U_{IN} - U_{T})^2$$
5. Operational Amplifier.
Parameters:
① Supply voltage: \(V_{CC}\)
② Open-loop gain (open-loop gain): \(A\)
$$U_{O} = A(U_{+} - U_{-}) = AU_{d}$$
\(U_{d}\) is the basic function of the operational amplifier, which is to amplify.
The different operational amplifiers have different A values, which are very large and change with temperature.
③ Input resistance \(R_{i}\): The equivalent resistance of the input terminal of the operational amplifier from the inverting input terminal and the non-inverting input terminal.
\(M\Omega\) level.
④ Output resistance \(R_{o}\): The equivalent resistance of the output terminal of the operational amplifier and the ground terminal.
\(\Omega\) level.
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**⑤ Saturation Voltage Udsat**
In the input Uds in (-Udsat ~ +Udsat) range, Uo = Au1 holds, this is the linear region.
In the input Uds in (-∞ -Udsat) V(+Udsat, +∞) range, the output of the amplifier is -Udsat or +Udsat.
This is equivalent to a voltage source externally, this is the positive (negative) saturation region.
**DC or low-frequency operational amplifier circuit model. (From the ideal perspective, Ri→∞, Ro→0)**
Simplification:
$$ u_{o} = A(u_{+} - u_{-}) $$
**Connect the operational amplifier directly to the signal source:**
Based on the following reasons, this operational amplifier circuit is not practical:
1. The difference between u+ and u- is too small (otherwise it's not in the linear region), the input and output voltage difference is too large.
2. The open-loop gain of different operational amplifiers is very different, it is difficult to match them in a circuit.
3. The open-loop gain of the operational amplifier changes with temperature, this cannot maintain the normal operation of the circuit.
To solve the above problems, it is necessary to feedback part of the output back to the input (feedback to the inverting input terminal: negative feedback; feedback to the non-inverting input terminal: positive feedback).
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Ideal Op-Amp:
# Negative Feedback Op-Amp Circuit:
$$
\begin{aligned}
& u_{o} = -A u_{i} \\
& i = \frac{u_{i} - u_{o}}{R_{1}} \\
& i = \frac{u_{i} - u_{o}}{R_{f}} \rightarrow \frac{u_{o}}{u_{i}} = -\frac{A R_{f}}{(R_{f} + R_{1}) + A R_{1}} \\
& -A u_{i} = u_{o}
\end{aligned}
$$
Since R1 and Rf are in the kΩ range, A is in the range of 10^5 to 10^8, so uo is approximately -Rf/R1 and independent of A.
1) Since -U_sat < uo < U_sat, -U_sat < uo/R1 < U_sat.
The op-amp input voltage requirements are much lower than without feedback.
2) Input voltage u_i and output voltage u_o are in the same order of magnitude (same).
3) A is temperature-independent and needs to be sufficiently large.
# Ideal Op-Amp:
Properties:
1. Input resistance R_in is ∞ → i+ = i- = 0: virtual short
2. Output resistance R_out is 0 → uo = A(u+ - u-) + uRo(=0)
3. Open-loop gain A is ∞ → ∞(u+ - u-) = uo ∈ [-U_sat, +U_sat]. u+ = u-: virtual short.
Example:
1. Voltage follower.
2. Inverting amplifier.
$$
\frac{u_{o}}{R_{1}} = -\frac{R_{f}}{R_{1}} u_{i}
$$
Page 12
3) Common-Mode Amplifier
$$ u_{o} = u_{1} + u_{2} + u_{3} = -\frac{R_{1}}{R_{2}} u_{1} $$
$$ i_{+} = i_{-} = 0 $$
$$ u_{1} = \frac{R_{2}}{R_{1} + R_{2}} u_{o} \Rightarrow u_{o} = (1 + \frac{R_{2}}{R_{1}}) u_{1} $$
4) Differential Amplifier
$$ u_{o} = -\left(\frac{R_{1}}{R_{1}} u_{1} + \frac{R_{2}}{R_{2}} u_{2} + \frac{R_{3}}{R_{3}} u_{3}\right) $$
5) Subtractor
$$ u_{o} = -\frac{R_{1}}{R_{1} + R_{2}} u_{1} $$
6) Voltage-Controlled Current Source
$$ u_{o} = -\frac{R_{1}}{R_{1} + R_{2}} u_{1} $$
7) Negative Resistance
$$ u_{1} = u_{2} $$
$$ u_{2} = -\frac{R_{1}}{R_{2}} u_{1} $$
$$ u_{1} = u_{2} $$
8) Voltage Comparator (No Feedback)
$$ u_{o} > u_{ref} \text{, then output } -u_{in} $$
$$ u_{o} < u_{ref} \text{, then output } u_{sat} $$
Page 13
Positive and Negative Feedback Operational Amplifier Circuit
Assume a small positive noise is suddenly generated at the output end. Thus, the voltage at the + input increases slightly. Since \( u_+ = A(u_+ - u_-) \), and \( A \) is very large, \( u_+ \) exceeds the linear region. Hence, \( u_+ \) directly becomes \( +U_{sat} \). Conversely, if a small negative noise is generated at the output end, \( u_- \) will become \( -U_{sat} \).
Property ①: Due to the input resistance being infinitely large, the virtual short circuit still holds.
Property ②: Since there is no \( u_+ = u_- \in [-U_{sat}, +U_{sat}] \) relationship, the virtual short circuit no longer holds.
Property ③: \( A \to \infty \)
1. Feedback Comparator
Assume a noise is generated. The operational amplifier's output becomes \( +U_{sat} \). According to the virtual short circuit, \( u_+ = \frac{R_1}{R_1 + R_2} U_{sat} \). When \( u_i < \frac{R_1}{R_1 + R_2} U_{sat} \), the operational amplifier's output is \( U_{sat} \). When \( u_i \) increases to exceed \( \frac{R_1}{R_1 + R_2} U_{sat} \), due to the positive feedback, the output becomes \( -U_{sat} \). According to the virtual short circuit, \( u_+ = -\frac{R_2}{R_1 + R_2} U_{sat} \). Once \( u_i \) decreases to below \( -\frac{R_2}{R_1 + R_2} U_{sat} \), the output reverts to \( -U_{sat} \).
The feedback comparator increases to \( \frac{R_1}{R_1 + R_2} U_{sat} \) or decreases to \( -\frac{R_2}{R_1 + R_2} U_{sat} \). The output changes. This characteristic can be used in signal detection to some extent (within the feedback width) to eliminate noise interference.
2. Pulse Sequence Generator
Assume a small disturbance causes the output voltage \( u_o = -U_{sat} \). When \( u_+ = -0.5 U_{sat} \), the capacitor starts charging. The voltage across the capacitor \( u_C \) is given by:
$$ u_C = -U_{sat} + [0.5U_{sat} - (-U_{sat})] e^{-\frac{t}{RC}} $$
When \( u_C \) reaches \( -0.5 U_{sat} \), \( u_0 \) jumps to \( U_{sat} \). At this point, \( u_+ = 0.5 U_{sat} \). The capacitor starts discharging:
$$ u_C = U_{sat} + [0.5U_{sat} - (-U_{sat})] e^{-\frac{t}{RC}} $$
Page 14
Three-Port Network
# Table 1:
| Parameters | Conductance Parameters | Resistance Parameters | Transmission Parameters | Mixed Parameters |
|------------|------------------------|-----------------------|-------------------------|------------------|
| **Equations** | $$\left(\begin{array}{l}I_{1} \\ I_{2}\end{array}\right)=\left(\begin{array}{cc}G_{11} & G_{12} \\ G_{21} & G_{22}\end{array}\right)\left(\begin{array}{l}U_{1} \\ U_{2}\end{array}\right)$$ | $$\left(\begin{array}{l}U_{1} \\ U_{2}\end{array}\right)=\left(\begin{array}{cc}R_{11} & R_{12} \\ R_{21} & R_{22}\end{array}\right)\left(\begin{array}{l}I_{1} \\ I_{2}\end{array}\right)$$ | $$\left(\begin{array}{l}U_{1} \\ I_{1}\end{array}\right)=\left(\begin{array}{cc}T_{11} & T_{12} \\ T_{21} & T_{22}\end{array}\right)\left(\begin{array}{l}U_{2} \\ -I_{2}\end{array}\right)$$ | $$\left(\begin{array}{l}U_{1} \\ I_{2}\end{array}\right)=\left(\begin{array}{cc}H_{11} & H_{12} \\ H_{21} & H_{22}\end{array}\right)\left(\begin{array}{l}I_{1} \\ U_{2}\end{array}\right)$$ |
| **Symmetry Conditions** | $$G_{12}=G_{21}$$ | $$R_{12}=R_{21}$$ | $$T_{11}T_{22}-T_{12}T_{21}=1$$ | $$H_{12}=-H_{21}$$ |
| **Symmetry Conditions** | $$G_{11}=G_{22}$$ | $$R_{11}=R_{22}$$ | $$T_{11}=T_{22}$$ | $$H_{11}H_{22}-H_{12}H_{21}=1$$ |
# Table 2:
| Parameters | Conductance Parameters | Resistance Parameters | Transmission Parameters | Mixed Parameters |
|------------|------------------------|-----------------------|-------------------------|------------------|
| **Resistance Parameters** | $$\frac{R_{22}}{R_{21}}-\frac{R_{21}}{R_{22}}$$ | $$\frac{T_{12}}{T_{11}}-\frac{\Delta T}{T_{11}}$$ | $$\frac{1}{T_{21}}$$ | $$\frac{H_{12}}{H_{22}}$$ |
| **Conductance Parameters** | $$\frac{R_{22}}{R_{21}}-\frac{R_{21}}{R_{22}}$$ | $$\frac{T_{12}}{T_{11}}-\frac{\Delta T}{T_{11}}$$ | $$\frac{1}{T_{21}}$$ | $$\frac{H_{12}}{H_{22}}$$ |
| **Transmission Parameters** | $$\frac{1}{R_{21}}$$ | $$\frac{R_{22}}{R_{21}}-\frac{R_{21}}{R_{22}}$$ | $$\frac{T_{12}}{T_{11}}-\frac{\Delta T}{T_{11}}$$ | $$\frac{1}{H_{21}}$$ |
| **Mixed Parameters** | $$\frac{1}{R_{21}}$$ | $$\frac{R_{22}}{R_{21}}-\frac{R_{21}}{R_{22}}$$ | $$\frac{T_{12}}{T_{11}}-\frac{\Delta T}{T_{11}}$$ | $$\frac{1}{H_{21}}$$ |
# From R Parameters and G Parameters Viewpoint:
$$\left\{\begin{array}{l}i_{1}=\left(G_{11}+G_{12}\right)u_{1}-G_{12}u_{2} \\ u_{1}=\left(R_{1}+R_{2}\right)i_{1}+R_{3}i_{2}\end{array}\right.$$
Page 15
The page contains handwritten notes on electrical circuits, specifically focusing on negative resistance circuits, bipolar junction transistors (BJTs), and equivalent circuits for two-terminal networks. Here's a breakdown of the content:
---
Negative Resistance Circuit Analysis
Given the circuit shown in
, we can analyze the following relationships:
$$
T_{11} = \frac{U_1}{U_2} = 1, \quad T_{12} = \frac{U_1}{I_2} = 0
$$
$$
T_{21} = \frac{I_1}{U_2} = 0, \quad T_{22} = \frac{I_1}{I_2} = -\frac{R_2}{R_1}
$$
From these, we can write the voltage and current relationships:
$$
\begin{pmatrix}
U_1 \\
I_1
\end{pmatrix}
=
\begin{pmatrix}
1 & 0 \\
0 & -\frac{R_2}{R_1}
\end{pmatrix}
\begin{pmatrix}
U_2 \\
I_2
\end{pmatrix}
$$
Given that \(U_2 = -R_2 I_2\), we find:
$$
R_1 = \frac{U_1}{I_1} = -\frac{R_1}{R_2} R < 0
$$
---
Bipolar Junction Transistor (BJT) Circuit Symbols and Small-Signal Circuit Model
The circuit symbol for a BJT is shown in
. The small-signal model of a BJT can be represented as:
$$
\begin{pmatrix}
\Delta U_{be} \\
\Delta I_{c}
\end{pmatrix}
=
\begin{pmatrix}
R_{be} & \mu \\
\beta & \frac{1}{R_{ce}}
\end{pmatrix}
\begin{pmatrix}
\Delta I_{b} \\
\Delta U_{ce}
\end{pmatrix}
$$
---
Equivalent Circuits for Two-Terminal Networks
The equivalent circuits for a two-terminal network are shown in
. The formulas for the resistances and conductances are:
$$
R_{11} = \frac{U_1}{I_1} = R_a + R_b
$$
$$
G_{11} = \frac{I_1}{U_1} = G_a + G_b
$$
$$
T_{11} = \frac{U_1}{I_2} = R_a + R_b
$$
$$
R_{12} = \frac{U_1}{I_2} = R_b
$$
$$
G_{12} = \frac{I_1}{U_2} = -G_b
$$
$$
T_{12} = -\frac{U_1}{I_2} = \frac{R_a R_b + R_b R_c + R_c R_a}{R_2}
$$
$$
R_{21} = \frac{U_2}{I_1} = R_b
$$
$$
G_{21} = \frac{I_2}{U_1} = -G_b
$$
$$
T_{21} = \frac{I_2}{U_1} = \frac{1}{R_2}
$$
$$
R_{22} = \frac{U_2}{I_2} = R_b + R_c
$$
$$
G_{22} = \frac{I_2}{U_2} = G_b + G_c
$$
$$
T_{22} = -\frac{I_2}{I_2} = 1 + \frac{R_2}{R_1}
$$
The resistances and conductances can be expressed as:
$$
\begin{cases}
R_b = R_{12} = R_{21} \\
R_a = R_{11} - R_{12} \\
R_c = R_{22} - R_{21}
\end{cases}
$$
$$
\begin{cases}
G_{1b} = -G_{12} = -G_{21} \\
G_{a} = G_{11} + G_{12} \\
G_{c} = G_{22} + G_{21}
\end{cases}
$$
$$
\begin{cases}
R_1 = \frac{I_1}{T_{21}} \\
R_2 = \frac{1}{T_{21}}
\end{cases}
$$
Page 16
2. Two-Port Network Connections
1. Series Connection
$$
\begin{aligned}
& \text{By } [u_1] = T_1 [-i_1], \quad [u_2] = T_2 [-i_2] \\
& \therefore [u_1] = T_1 T_2 [-i_2] \quad \therefore T = T_1 T_2
\end{aligned}
$$
2. Parallel Connection
$$
\begin{aligned}
& \text{By } u_1 = u_1' = u_1'', \quad u_2 = u_2' = u_2'' \\
& \therefore i_1 = i_1' + i_1'', \quad i_2 = i_2' + i_2''
\end{aligned}
$$
$$
\begin{aligned}
& \therefore [u] = [u'] + [u''] = (G' + G'') [u] \\
& \therefore G = G' + G''
\end{aligned}
$$
3. Parallel Connection
$$
\begin{aligned}
& \text{Since the two ports have a common terminal, connecting them in parallel does not violate the two-port condition.} \\
& \therefore R = R' + R''
\end{aligned}
$$
Page 17
Linear Resistive Circuit Analysis
# 1. Node Voltage Method:
In the circuit, select one node as the reference node, setting its voltage to zero. The voltage of other nodes is called the node voltage \(U_n\), \(U_m\), etc. The circuit automatically satisfies Kirchhoff's Current Law (KCL). Only write the (n-1) KCL equations at the nodes.
1. If the circuit only contains current sources, voltage sources, and resistors, then there is a general form:
- Mutual conductance is positive, mutual resistance is negative. Actual voltage sources are converted to actual current sources. This is a symmetrical circuit.
2. If the circuit contains dependent sources, first convert the dependent source into an independent source, write the node equation, and then write the control quantity and node voltage relationship equation.
3. If the circuit contains resistors in series with ideal current sources or resistors in parallel with ideal voltage sources, then the resistance in the equation has no effect, and it causes the current at a certain node to be known or the voltage at two nodes to be known.
4. If there are two nodes connected by a pure voltage source (or dependent voltage source), you can write the node equation by selecting the reference node at the negative terminal of the voltage source, adding the voltage source branch current, and adding the voltage source into the generalized node. (When using the generalized node method, the concept of "mutual conductance" is expanded)
# 2. Mesh Current Method:
In the circuit mesh, assume the mesh current, making the actual current on each branch the algebraic sum of the currents in all meshes. The mesh current automatically satisfies Kirchhoff's Current Law (KCL). Only write the (b-n+1) mesh KCL equations.
1. If the circuit only contains current sources, voltage sources, and resistors, then there is a general form:
- The currents in the two meshes are the same when they are positive, and opposite when they are negative. The voltage source's voltage direction is opposite to the mesh current (parallel) when it is positive. (Compare with the node voltage method, the current flowing into the node is positive).
2. If the circuit contains dependent sources, treat them as independent sources and write the equation, and then find the relationship between the control quantity and the mesh current.
3. If there are current sources in parallel with resistors, convert them to voltage sources. If there are resistors in parallel with ideal voltage sources, the current source and the resistor in series with the ideal voltage source are not considered.
Page 18
4. Regardless of whether there is a resistor in the common branch of the two loops, as long as there is a current source, it can be used.
- When selecting a loop, ensure the current source is not part of any loop.
- Increase the current source's voltage.
- Define the generalized mesh (with equations of neighboring meshes and its own KVL constraints).
3. Superposition Theorem
The response (current or voltage between two points in the circuit) and the excitation (independent power source) satisfy superposition.
Since the branch voltage and branch current can be expressed linearly in terms of the branch voltage, the linear resistive circuit's response and excitation satisfy superposition.
Note: When a controlled source is in the circuit, the controlled relationship remains unchanged. The effect of the controlled source is only reflected in the circuit containing the independent source, not in the superposition.
- Voltage sources not in use are set to zero → short circuit
- Current sources not in use are set to zero → open circuit
4. Homogeneity Theorem
The response and excitation satisfy homogeneity (linear equations are linear).
When all independent sources change by k times, the response also changes by k times (including controlled sources).
5. Replacement Theorem
Assuming ab contains an independent source and a resistor.
The voltage u = u0 - R0i.
The current i = u0 / R0.
The voltage u = R0i.
The current i = u0 / R0.
The voltage u = u0 - R0i.
The current i = u0 / R0.
The voltage u = R0i.
The current i = u0 / R0.
The voltage u = u0 - R0i.
The current i = u0 / R0.
The voltage u = R0i.
The current i = u0 / R0.
The voltage u = u0 - R0i.
The current i = u0 / R0.
The voltage u = R0i.
The current i = u0 / R0.
The voltage u = u0 - R0i.
The current i = u0 / R0.
The voltage u = R0i.
The current i = u0 / R0.
The voltage u = u0 - R0i.
The current i = u0 / R0.
The voltage u = R0i.
The current i = u0 / R0.
The voltage u = u0 - R0i.
The current i = u0 / R0.
The voltage u = R0i.
The current i = u0 / R0.
The voltage u = u0 - R0i.
The current i = u0 / R0.
The voltage u = R0i.
The current i = u0 / R0.
The voltage u = u0 - R0i.
The current i = u0 / R0.
The voltage u = R0i.
The current i = u0 / R0.
The voltage u = u0 - R0i.
The current i = u0 / R0.
The voltage u = R0i.
The current i = u0 / R0.
The voltage u = u0 - R0i.
The current i = u0 / R0.
The voltage u = R0i.
The current i = u0 / R0.
The voltage u = u0 - R0i.
The current i = u0 / R0.
The voltage u = R0i.
The current i = u0 / R0.
The voltage u = u0 - R0i.
The current i = u0 / R0.
The voltage u = R0i.
The current i = u0 / R0.
The voltage u = u0 - R0i.
The current i = u0 / R0.
The voltage u = R0i.
The current i = u0 / R0.
The voltage u = u0 - R0i.
The current i = u0 / R0.
The voltage u = R0i.
The current i = u0 / R0.
The voltage u = u0 - R0i.
The current i = u0 / R0.
The voltage u = R0i.
The current i = u0 / R0.
The voltage u = u0 - R0i.
The current i = u0 / R0.
The voltage u = R0i.
The current i = u0 / R0.
The voltage u = u0 - R0i.
The current i = u0 / R0.
The voltage u = R0i.
The current i = u0 / R0.
The voltage u = u0 - R0i.
The current i = u0 / R0.
The voltage u = R0i.
The current i = u0 / R0.
The voltage u = u0 - R0i.
The current i = u0 / R0.
The voltage u = R0i.
The current i = u0 / R0.
The voltage u = u0 - R0i.
The current i = u0 / R0.
The voltage u = R0i.
The current i = u0 / R0.
The voltage u = u0 - R0i.
The current i = u0 / R0.
The voltage u = R0i.
The current i = u0 / R0.
The voltage u = u0 - R0i.
The current i = u0 / R0.
The voltage u = R0i.
The current i = u0 / R0.
The voltage u = u0 - R0i.
The current i = u0 / R0.
The voltage u = R0i.
The current i = u0 / R0.
The voltage u = u0 - R0i.
The current i = u0 / R0.
The voltage u = R0i.
The current i = u0 / R0.
The voltage u = u0 - R0i.
The current i = u0 / R0.
The voltage u = R0i.
The current i
Page 19
6. Thevenin's Theorem:
For any circuit composed of linear resistors, linear controlled sources, and independent voltage sources, the circuit can be simplified to a voltage source in series with a resistor.
$$U_{0}$$ is the open-circuit voltage.
The equivalent resistance is the total resistance of the circuit when all independent sources are set to zero.
(1) The open-circuit voltage can be calculated using the voltage drop method, loop current method, superposition theorem, and simple resistance circuit analysis methods.
(2) The resistance can be calculated using the equivalent resistance method.
(3) The controlled source's controlled quantity in the circuit cannot be equivalent to $$U_{0}$$ and $$R_{i}$$ when the controlled quantity is outside the circuit.
(4) The resistance can be negative.
(5) As long as the circuit is linearly equivalent, it can be transformed.
Norton's Theorem: $$I_{0}$$, $$G_{i}$$ ↔ $$U_{0}$$, $$R_{i}$$
7. Kirchhoff's Current Law:
For any network N and $$\hat{N}$$ with the same topology, if the reference directions of the branches are the same, and the voltages and currents of the branches are taken as the same reference direction, then:
$$\sum_{k=1}^{n} u_{k} i_{k} = 0$$
Proof: Suppose k branches are connected between nodes α and β.
$$U_{k}$$ = $$U_{\alpha}$$ - $$U_{\beta}$$
$$U_{k}$$ = $$U_{\alpha}$$ $$i_{\alpha}$$ - $$U_{\beta}$$ $$i_{\beta}$$ = $$U_{\alpha}$$ $$i_{\alpha}$$ + $$U_{\beta}$$ $$i_{\beta}$$
Where $$i_{\alpha}$$ represents the current flowing out of node α, and $$i_{\beta}$$ represents the current flowing out of node β.
The sum of the currents flowing through all branches in the circuit is zero.
$$U_{\alpha}$$ $$i_{\alpha}$$ + $$U_{\beta}$$ $$i_{\beta}$$ + ... + $$U_{k}$$ $$i_{k}$$ = 0
Page 20
The text and formulas extracted from the handwritten note are as follows:
---
The text at the top of the page discusses the transformation of a circuit's voltage into nodal voltage and the subsequent combination of currents at the same node. It leads to the following expression:
$$\sum_{k=1}^{k} u_{n} \hat{I}_{n} = u_{n,1} \sum_{k=1}^{k} \hat{I}_{n} + ... + u_{n,k} \sum_{k=1}^{k} \hat{I}_{n} + ... + u_{n,m} \sum_{k=1}^{k} \hat{I}_{n}$$
From this, it is deduced that:
$$\sum_{k=1}^{k} \hat{I}_{n} = 0$$
Thus,
$$\sum_{k=1}^{k} u_{n} \hat{I}_{n} = 0$$
---
The section titled "8. Ohm's Law" discusses the relationship between voltage and current in a circuit. It presents two forms of Ohm's Law:
1. Form 1: $$\frac{u_{1}(t)}{u_{2}(t)} = \frac{i_{1}(t)}{i_{2}(t)}$$ or $$u_{1}(t) i_{2}(t) = u_{2}(t) i_{1}(t)$$
The proof provided states that in the left diagram, there are b branches, and the circuit within the box has b-2 branches. The voltage and current on these branches are denoted as u_k(t) and i_k(t) for k=3, ..., b. In the right diagram, the corresponding voltage and current are denoted as u_k(t) and i_k(t) for k=3, ..., b. According to Kirchhoff's Current Law:
$$\left\{\begin{array}{l}
u_{1}(t) i_{1}(t) + 0 + \sum_{k=3}^{b} u_{k}(t) i_{k}(t) = 0 \\
0 + u_{2}(t) i_{2}(t) + \sum_{k=3}^{b} u_{k}(t) i_{k}(t) = 0
\end{array}\right.$$
Since the left and right diagrams represent the same circuit, it follows that:
$$u_{1}(t) i_{1}(t) = i_{1}(t) R, u_{2}(t) i_{2}(t) = i_{2}(t) u_{2}(t)$$
Thus,
$$\sum_{k=3}^{b} u_{k}(t) i_{k}(t) = \sum_{k=3}^{b} u_{k}(t) i_{k}(t)$$
Therefore,
$$u_{1}(t) i_{1}(t) = u_{2}(t) i_{2}(t)$$
This implies:
$$G_{21} = \left.\frac{u_{2}(t)}{u_{1}(t)}\right|_{i_{2}=0} = G_{12} = \left.\frac{i_{1}(t)}{u_{1}(t)}\right|_{i_{1}=0}$$
This is the necessary and sufficient condition for two-terminal mutual conductance.
---
The section concludes with the following:
$$\frac{u_{1}(t)}{u_{2}(t)} = \frac{i_{1}(t)}{i_{2}(t)} \quad \Leftrightarrow \quad i_{1}(t) u_{2}(t) = i_{2}(t) u_{1}(t) \quad \Leftrightarrow \quad R_{21} = R_{12}$$
---
The text at the bottom of the page discusses the relationship between voltage and current in a circuit, specifically in the context of mutual conductance. It states that the mutual conductance G_{21} is equal to the mutual conductance G_{12}, and that this is the necessary and sufficient condition for two-terminal mutual conductance. The final equation shows that the mutual conductance is equal to the reciprocal of the resistance between the two terminals.
Page 21
1. When performing mesh analysis, the relative direction of current and voltage must remain consistent (either all consistent or all opposite).
2. Combine the superposition theorem and mesh theorem to apply to multiple voltage sources (current sources) and only solve the current (voltage) of a branch when it is convenient.
Circuit Theory - Duality Principle
Graph: {nodes, branches}; Directed graph: all branch currents have a reference direction (voltage is associated).
Connected graph: all nodes and branches are connected; Subgraph: G' (nodes, branches) ⊂ G (nodes, branches)
Tree: connected, includes all nodes, no loops. (Of course, tree T is a subgraph of G).
Tree branches: branches in T; Branches: branches not in T.
It is easy to know that a graph with n nodes needs to add n-1 branches to form a tree.
In a graph G with n nodes and b branches, the tree branches: n-1, the loop branches: b-(n-1)
1. **Adjacency Matrix A**
Use an n×b matrix to represent the branch-node adjacency relationship. Let
$$a_{ij} = \begin{cases}
1 & \text{branch } j \text{ is connected to node } i, branch leaves node} \\
-1 & \text{branch } j \text{ is connected to node } i, branch points to node} \\
0 & \text{branch } j \text{ is not related to node } i.
\end{cases}$$
The augmented adjacency matrix Aa ∈ Mn×b. It is known that Aa has n-1 linearly independent rows (nodes).
We can delete one row to form an (n-1)×b adjacency matrix A, deleting the row (node) as the reference node.
Let branch currents $\vec{I} = (i_1, ..., i_b)^T$, branch voltages $\vec{U} = (u_1, ..., u_b)^T$,
Node voltages $\vec{U}_n = (u_{n1}, ..., u_{nn})^T$, u_{nx} = 0 (reference node)
Then Aa$\vec{I}$ = 0 $\Rightarrow$ A$\vec{I}$ = 0
And $\vec{U}$ = A^T$\vec{U}_n$ $\Rightarrow$ Rank A = n-1. In a loop network with n nodes and b branches, the number of independent KCL equations is n-1.
Page 22
The note discusses network theory, specifically focusing on loops and branches in a network. It defines a loop as a closed path in the network, and a branch as a line segment between two nodes. The note explains that each loop must contain at least one branch, and each branch must be part of at least one loop. It also mentions that each loop must contain at least two branches. The rank of the fundamental loop matrix is defined as the number of non-zero elements in each row, which is equal to the number of branches minus the number of nodes plus one. The note also discusses the relationship between branch currents and voltages, and how to derive the loop equations from the branch equations. The final part of the note discusses the relationship between the loop matrix and the branch matrix, and how to derive the loop equations from the branch equations.
Page 23
Network Theory
# Terminology
- **Node**: Branch
- **Mesh**: Loop
- **Open Circuit**: Short Circuit
- **Voltage**: Current
- **Current**: Voltage
# Variables
- **Node Voltage**: Mesh Current
- **Mesh Voltage**: Branch Current
# Components
- **Resistance R**: Conductance G
- **Inductance L**: Capacitance C
- **Voltage Source Us**: Current Source Is
# Connections
- **Series**: Parallel
- **Star (Y)**: Delta (Δ)
- **Kirchhoff's Current Law (KCL)**: Kirchhoff's Voltage Law (KVL)
# Theorems
- **Thevenin's Theorem**: Norton's Theorem
- **Superposition**: Superposition Theorem
Page 24
Nonlinear Resistance Circuit Analysis
**Definition:** \( u = f(i) \) or \( i = g(u) \)
**Example:** Diode: \( i = I_s (e^{\frac{u}{nV}} - 1) \)
**Properties:**
1. \( u-i \) relationship is non-linear and non-additive.
2. \( u-i \) relationship can be expanded in a Taylor series. Higher-order terms can be neglected (\( \geq 2 \)), then the small perturbations and their effects are linear.
3. May have multiple solutions or no solution.
1. **Direct Method**
- **Voltage-Controlled Nonlinear Resistance - Node Voltage Method.**
- **Current-Controlled Nonlinear Resistance - Mesh Current Method.**
2. **Graphical Method**
- Element ends and load ends/branch ends meet at the intersection point.
3. **Segment Linearization Method**
- "Assumption-Verification Method."
- Example: Diode four models.
\[
i = I_s (e^{\frac{u}{nV}} - 1)
\]
1. **Model 1.**
\[
\begin{cases}
i = 0, u < U_{sd} \\
u = U_{sd} + iR, i > 0.
\end{cases}
\]
2. **Model 2. (External resistance >> diode resistance).**
\[
\begin{cases}
i = 0, u < U_{sd} \\
u = U_{sd}, i > 0.
\end{cases}
\]
3. **Model 3. (U_{sd} is very small).**
\[
\begin{cases}
i = 0, u < 0 \\
u = R_i i, i > 0.
\end{cases}
\]
4. **Model 4. (Diode resistance and U_{sd} are very small).**
\[
\begin{cases}
i = 0, u < 0 \\
u = 0, i > 0.
\end{cases}
\]
From Model 1 to Model 4, the difference is getting larger and larger.
Page 25
4. Small Signal Method
Background: Steady-state excitation: U_s; Small perturbation ΔU_s(t)
1. Only consider DC excitation, solve for the nonlinear resistor operating point (U_0, I_0)
2. For a nonlinear resistor u=f(i), using Taylor expansion, we have:
u = u_0 + f'(i_0)(i - i_0) + f''(i_0)(i - i_0)^2 + ...
≈ u_0 + f'(i_0)(i - i_0)
Thus, Δu = ∂u/∂i * Δi (both are functions of time)
At this point, for the entire circuit, when only Δu excitation is present, it is linear. According to linear circuit analysis methods, by Δu, we can find ΔU, and then Δi = ∂u/∂u * Δu.
3. Superposition of two excitations:
$$\left\{\begin{array}{l}
u = u_0 + \Delta u(t) \\
i = I_0 + \Delta i(t)
\end{array}\right.$$
5. Examples
1. Half-wave rectifier - using diode model 4:
$$\overline{U} = \frac{1}{T} \int_0^T U_m \sin \omega t \, dt = \frac{U_m}{\pi}$$
Effective value U = $$\frac{1}{T} \int_0^T U_m^2 \sin^2 \omega t \, dt = \frac{U_m}{2\sqrt{2}}$$
2. Full-wave rectifier:
$$\overline{U} = \frac{2}{\pi} \int_0^T U_m \sin \omega t \, dt = \frac{2U_m}{\pi}$$
Effective value U = $$\frac{2}{T} \int_0^T U_m^2 \sin^2 \omega t \, dt = \frac{U_m}{\sqrt{2}}$$
2. Clipping (U_S = U_m sin ωt):
Page 26
3. Comparator.
$$u_{1}^{+}$$
$$u_{n1}$$
$$u_{n1} \geq u$$
$$u_{1}^{+}$$
$$u_{n2}$$
$$u_{n2} \leq u$$
$$u_{1}^{+}$$
$$u_{n1}$$
$$u_{n1} \geq u$$
$$u_{1}^{+}$$
$$u_{n2}$$
$$u_{n2} \leq u$$
4. Voltage Regulation.
$$-U_{Z}$$
$$-I_{Z_{\text{min}}}$$
$$+U_{Z}$$
$$-I_{Z_{\text{max}}}$$
Do not allow reverse current in a certain range ($I_{Z_{\text{min}}} < |I| < I_{Z_{\text{max}}}$), the terminal voltage will always be at $U = -U_{Z}$.
5. Utilize non-linear resistance to produce new frequency components. Requires complex mathematical calculations.
6. Use MOSFET to form an amplifier and gate circuit.
2. Simplify MOSFET circuit model:
$$i_{DS} = \frac{1}{2}U_{DS}^{2}$$
$$G_{n}$$ (N-channel enhancement type)
$$S$$
$$U_{T}, K$$
$$U_{DS}$$
When $U_{GS} < U_{T}$, $i_{DS} = 0$, it is disconnected.
When $U_{GS} > U_{T}$, it is conducting. At this point, $U_{DS} < U_{GS} - U_{T}$, D-S is a resistor. $R$ is constant.
When $U_{DS} > U_{GS} - U_{T}$, D-S is a voltage-controlled current source:
$$i_{DS} = \frac{1}{2}K(U_{GS} - U_{T})^{2}$$
$$R = \frac{U_{DS}}{i_{DS}} = \frac{U_{GS} - U_{T}}{\frac{1}{2}K(U_{GS} - U_{T})^{2}} = \frac{2}{K} \cdot \frac{1}{U_{GS} - U_{T}} = \frac{2}{K} \cdot \frac{1}{U_{DS}}$$
Page 27
1. **Amplifier**
When Ugs is a small signal, according to the "one assumption, one verification" segmented linearity method, solve the operating point. When Ugs contains a small signal, ΔUgs is the output, ΔUgs is the input, then the amplification factor is:
$$\frac{\Delta Ugs}{\Delta Ugs} = \frac{\Delta Ugs}{\Delta Ugs} \cdot \frac{\Delta Ugs}{\Delta Ugs} = \frac{\Delta Ugs}{\Delta Ugs} \cdot \frac{\Delta Ugs}{\Delta Ugs} = k \cdot \frac{Ugs - Ugs}{Ugs - Ugs} \cdot R_L$$
Where R_L is the equivalent resistance seen from the DS terminal.
When Ugs = U + ΔU, the combination of the above two is called a common-source amplifier circuit.
2. **Gate Circuit**
According to the truth table (n+1 columns, 2^n+1 rows, n being the number of logical variables),
↓
Find all combinations of inputs that make the output true.
↓
Combine these combinations using logical operations to form a new unified logical expression.
↓
Simplify the logical expression.
↓
Use logical basic units to implement the expression:
Inverter: A → Y: U_i → U_o Y = A
Buffer: A → Y: A → Y: Y = A. Prevent signal attenuation during transmission.
NAND Gate: A → Y: Y = A̅B̅; NOR Gate: A → Y: Y = A̅ + B̅
Page 28
**Six. Dynamic Circuit Time Domain Analysis**
1. Dynamic Components (Energy Storage Components) (Linear Non-Time-Varying)
| Component | Capacitor | Inductor |
|-----------|-----------|----------|
| Charge Equation | q = Cu, i = dq/dt | Ψ = Li, u = dΨ/dt |
| Memory and Continuity | u = 1/C ∫ dt + 1/L ∫ dt | i = 1/L ∫ dt + 1/C ∫ dt |
| Relation | u + i = 0 | u - i = 0 |
| Energy | w = ∫ pdt = ∫ u dt | w = ∫ pdt = ∫ u dt |
| Actual (DC/AC) | u = C ∫ dt | u = L ∫ dt |
| Series | 1/C = Σ 1/Ci | L = Σ Li |
| Parallel | C = Σ Ci | 1/L = Σ 1/Li |
| Switching | u(0+) = u(0-) + 1/C ∫ dt | i(0+) = i(0-) + 1/L ∫ dt |
| High Frequency Effects | Capacitive Reactance, MOSFET Gate Capacitance (e.g., Cgs) | Inductive Reactance |
| High Voltage Effects | Breakdown (Needs Rated Voltage) | Magnetic Force Exceeds Mechanical Strength, Core Overheats (Needs Rated Current) |
**Description**
The system of linear constant coefficient ordinary differential equations (ODEs) is:
$$
\begin{cases}
\frac{d^2q}{dt^2} + R\frac{dq}{dt} + \frac{1}{C}q = 0 \\
\frac{d^2i}{dt^2} + R\frac{di}{dt} + \frac{1}{L}i = 0
\end{cases}
$$
Page 29
2. Classical Method for Solving Dynamic Circuits
Free Response: General Solution of Homogeneous Differential Equations
Forced Response: Particular Solution of Non-Homogeneous Differential Equations
Conditions: AC or DC excitation
Reason: At t=0+, these types of excitations are present in any branch of the circuit
1. First-Order Dynamic Circuit
1) Described by a first-order linear homogeneous differential equation.
2) If a first-order circuit contains one dynamic element, it can be transformed into an RC or RL circuit.
3) Solve the homogeneous differential equation (without excitation) and the non-homogeneous differential equation (with excitation).
Form: Ae^(-t)
4) General solution is the sum of the homogeneous solution and the particular solution, determined by an initial condition.
(Engineering perspective: After 3τ~5τ transient process, the circuit reaches a new steady state)
Summarizing the above steps, we can find that the response of any branch in a first-order circuit can be simplified to a three-element solution.
Let f(t) be the voltage or current (response) of the branch, f(0) is the initial value, f(t)_{t→∞} is the forced response (DC and AC components), and τ is the time constant, then:
f(t) = f(t)_{t→∞} + Ae^(-t), t≥0
Substitute t=0+:
f(t) = f(t)_{t→∞} + [f(0) - f(t)_{t=0+}]e^(-t/τ)
Where:
f(t)_{t→∞} : Forced response
[f(0) - f(t)_{t=0+}]e^(-t/τ) : Free response
RC circuit: τ = RC, RL circuit: τ = L/R, R is the equivalent resistance seen at the dynamic element's terminals.
2. Second-Order Dynamic Circuit
1) Second-order homogeneous differential equation: Contains two dynamic elements with different dynamic properties or two dynamic elements with the same dynamic properties but not coupled.
Example:
$$\frac{d^2u}{dt^2} + 2\alpha\frac{du}{dt} + \omega_0^2u = f(t)$$
The following is the theory of second-order constant coefficient linear differential equations (non-homogeneous) with constant coefficients.
Page 30
The differential equation is:
$$\frac{d^2u}{dt^2} + 2\alpha\frac{du}{dt} + \omega_0^2u = f(t), 0$$
or
$$\frac{d^2u}{dt^2} + 2\alpha\frac{du}{dt} + \omega_0^2u = f(t), 0$$
Assuming u = Ae^(λt), we have:
$$\lambda^2e^{2\lambda t} + 2\alpha\lambda e^{2\lambda t} + \omega_0^2e^{2\lambda t} = 0$$
Thus,
$$\lambda^2 + 2\alpha\lambda + \omega_0^2 = 0$$
The characteristic equation is:
$$\lambda = \frac{-2\alpha \pm \sqrt{4\alpha^2 - 4\omega_0^2}}{2} = -\alpha \pm \sqrt{\alpha^2 - \omega_0^2}$$
When Δ > 0, there are two different real roots. The general solution is:
$$u = C_1e^{(\alpha - \sqrt{\alpha^2 - \omega_0^2})t} + C_2e^{(\alpha + \sqrt{\alpha^2 - \omega_0^2})t}$$
When Δ = 0, the characteristic equation has one solution u = e^(-αt). Using the method of undetermined coefficients, we find another linearly independent solution:
$$u = te^{-\alpha t}$$
The general solution is:
$$u = (C_1 + C_2t)e^{-\alpha t}$$
When Δ < 0, there are two conjugate complex roots -α ± j√(ω_0^2 - α^2). The general solution is:
$$u = C_1e^{-\alpha t}e^{j\sqrt{\omega_0^2 - \alpha^2}t} + C_2e^{-\alpha t}e^{-j\sqrt{\omega_0^2 - \alpha^2}t}$$
$$= e^{-\alpha t}(C_1\cos(\sqrt{\omega_0^2 - \alpha^2}t) + C_2\sin(\sqrt{\omega_0^2 - \alpha^2}t))$$
$$= (C_1\cos(\sqrt{\omega_0^2 - \alpha^2}t) + C_2\sin(\sqrt{\omega_0^2 - \alpha^2}t))$$
$$= ke^{-\alpha t}\sin(\sqrt{\omega_0^2 - \alpha^2}t + \phi)$$
k and φ are constants.
To draw the time-domain characteristics of the circuit parameters directly from the differential equation without solving the equation, we can:
1. First, find u and u' and their initial values.
2. Next, find u and u' at steady state.
3. Finally, determine the transient process characteristics from the characteristic equation.
If there is an excitation, according to the solution method of the second-order linear homogeneous differential equation, specifically when the excitation is a sine wave, we have:
$$u'' + 2\alpha u' + \omega_0^2u = A\sin(\omega t + \phi)$$
When A = 1, the steady-state solution is:
$$\sin(\omega t) = \frac{e^{j\omega t} - e^{-j\omega t}}{j2}$$
The steady-state solution is:
$$A\left(\frac{e^{j(\omega t + \phi)} - e^{-(j\omega t + \phi)}}{j2}\right)$$
Then,
$$-w^2\frac{A}{j2}e^{j(\omega t + \phi)} + w^2\frac{A}{j2}e^{-(j\omega t + \phi)} + \frac{2\alpha A}{j2}e^{j(\omega t + \phi)} + \frac{2\alpha A}{j2}e^{-(j\omega t + \phi)} = \frac{1}{j2}e^{j\omega t} - \frac{1}{j2}e^{-j\omega t}$$
$$+ w^2\frac{A}{j2}e^{j(\omega t + \phi)} - w^2\frac{A}{j2}e^{-(j\omega t + \phi)} = \frac{1}{j2}e^{j\omega t} - \frac{1}{j2}e^{-j\omega t}$$
Page 31
3. Superposition method to solve dynamic circuits.
Zero input response: linearly dependent on initial conditions (all initial conditions, i.e., Uo, Io...).
Zero state response: linearly dependent on excitation (all excitations, i.e., Us, Is...).
To find the overall response under any excitation, decompose the response into zero input and zero state.
Zero input can be obtained using the superposition method (first-order), characteristic root method (second-order), etc.
Zero state can be obtained by decomposing any excitation into a linear combination of simple excitations, and then integrating.
$f(t) = \sum_{k=0}^{N-1} f(k\Delta t) [s(t-k\Delta t) - s(t-(k+1)\Delta t)]$
$\therefore f(t) = \lim_{N\to\infty} \sum_{k=0}^{N-1} f(k\Delta t) [s(t-k\Delta t) - s(t-(k+1)\Delta t)]$
$= \lim_{N\to\infty} \sum_{k=0}^{N-1} f(k\Delta t) \Delta t \frac{1}{\Delta t} [s(t-k\Delta t) - s(t-(k+1)\Delta t)]$
$= \lim_{N\to\infty} \sum_{k=0}^{N-1} f(k\Delta t) \Delta t p(t-k\Delta t)$
where $p(t-k\Delta t) = \frac{1}{\Delta t} [s(t-k\Delta t) - s(t-(k+1)\Delta t)]$ is the unit impulse function delayed by kΔt.
According to the linearity of the circuit, $f(k\Delta t) \Delta t p(t-k\Delta t)$ in the branch of interest has a zero state response of $f(k\Delta t) \Delta t h(t-k\Delta t)$, where $h(t)$ is the unit impulse response of the circuit.
Therefore, the response in the branch of interest $h(t_0) = \lim_{N\to\infty} \sum_{k=0}^{N-1} f(k\Delta t) \Delta t h(t_0-k\Delta t)$
$= \int_0^{t_0} f(\tau) h(t_0-\tau) d\tau$
Page 32
When N approaches infinity, ΔT approaches dT, kΔT approaches T, the unit impulse function becomes the unit impulse function p(t) → δ(t). The corresponding unit impulse function's zero-state response becomes the unit impulse response h_p(t) → h(t). Therefore, the zero-state response N(t) = ∫_0^t f(τ)h(t-τ)dτ.
Below, the method for calculating the unit impulse response h(t) is explained:
Definition: The limit of the unit impulse function: ∫_0^∞ δ(t)dt = 1, δ(t) = 0 (t ≠ 0).
Delay: δ(t - t_0) = 0 (t ≠ t_0), ∫_0^∞ δ(t - t_0)dt = 1.
And kδ(t - t_0) represents a unit impulse function at t_0 with strength k.
Properties:
(1) ∫_0^t δ(τ - t_0)dτ = { 0 if t < t_0, 1 if t > t_0. }
Thus, d/dt δ(t - t_0) = δ(t - t_0).
(2) Linearity: f(t) * δ(t - t_0) = f(t_0) * δ(t - t_0).
∫_0^∞ f(t) * δ(t - t_0)dt = f(t_0) * ∫_0^∞ δ(t - t_0)dt = f(t_0).
Response:
(1) Using the definition to find h(t), if the input is δ(t - t_0), then for t_0 ~ t_0^+, t_0^+ ~ +∞, the zero-state response can be found.
(2) Using the property ∂/∂t ∑(t - t_0) = δ(t - t_0) to find it.
Given the unit step function e(t) corresponding to the zero-state response (unit step response) as s(t), due to the zero-state linearity, s(t) has a zero-state response of s(t); the zero-state response of e(t - Δ) is s(t - Δ), which is evident.
h(t) = lim_Δ→0 [s(t) - s(t - Δ)] = ∂/∂t s(t) (Given: ∂/∂t s(t) = lim_Δ→0 [s(t) - s(t - Δ)] = ∂/∂t s(t)).
The zero-state response of the unit step is easy to find: A * s(t - t_0) → A * s(t - t_0).
Therefore, by the zero-state response and the zero-input response, the convolution of any input can be obtained.
Page 33
4. State Variable Method
1. State Equation:
$$\dot{\overline{X}} = A\overline{X} + B\overline{V}$$
- $\overline{X}$: State variables - independent $U_c$ and $U_i$.
- $\dot{\overline{X}}$: First-order derivative of state variables - $\dot{U_c}$ and $\dot{U_i}$.
- $\overline{V}$: All excitation $U_s$ and $I_s$.
1) Can be used for linear networks and nonlinear networks.
2) Similar to output equation $\overline{Y} = C\overline{X} + D\overline{V}$, where $\overline{Y}$ is the output vector.
3) According to the superposition principle, replace $C$ with $-\Theta$ and $L$ with $-\Omega$. This results in a new circuit with $n$ (state variables) + $m$ (independent sources). Solve for each power source ($m+n$) individually and add them up, dividing by the corresponding $C$ or $L$. This yields $\overline{X}$, which can be used to derive the state equation $\dot{\overline{X}} = A\overline{X} + B\overline{V}$.
2. Solution Methods: Characteristic Value Method, Laplace Transform Method.
5. Example: Circuit Simulation of Differential Equation
$$\ddot{y} + a\dot{y} + by = cE$$
Page 34
**Analysis of Dynamic Circuits under Sinusoidal Excitation**
1. **Analysis Foundation (Sinusoidal Elements, Power) and Examples**
Theoretically, solving non-homogeneous differential equations can resolve the response under sinusoidal excitation. However, through the method of complex numbers, the solution of the differential equation is transformed into solving algebraic equations, simplifying the response under sinusoidal excitation. At the same time, the calculation of power is also simplified. After using the Fourier series, the response and power of dynamic circuits under any non-sinusoidal periodic excitation can be easily calculated.
Sinusoidal excitation: \( i = I_m \sin(\omega t + \varphi_i) \). The effective value \( I = \sqrt{\frac{1}{T} \int_0^T i^2 dt} = \frac{I_m}{\sqrt{2}} \).
The result of differentiation, integration, and addition of the same frequency is still a sinusoidal quantity. Therefore, the voltage and current in linear circuits are all sinusoidal quantities (all obtained through the above calculation).
When analyzing sinusoidal steady-state circuits, for sinusoidal elements, we can first not consider the frequency, only considering the amplitude and phase.
\[
\begin{aligned}
&\because e^{j(\omega t + \varphi)} = \cos(\omega t + \varphi) + j \sin(\omega t + \varphi) \\
&\therefore \cos(\omega t + \varphi) = \text{Re}(e^{j(\omega t + \varphi)}) \\
&\sin(\omega t + \varphi) = I_m e^{j(\omega t + \varphi)} \\
&\therefore i = I_m \sin(\omega t + \varphi) = I_m I_m e^{j(\omega t + \varphi)} = I_m [I_m e^{j(\omega t + \varphi)}] \\
&= I_m [I_m e^{j\varphi} e^{j\omega t}] \\
&\therefore i = I e^{j\varphi} \quad \text{and} \quad I < \varphi. \\
&\therefore i = I_m [I e^{j\omega t}].
\end{aligned}
\]
In the determined frequency \(\frac{2\pi}{T}\), \(i\) and \(I\) have a one-to-one correspondence. The operation of \(i\) can be converted into the operation of \(I\).
(1) **Expression of \(i\)**
\(i\) has two expression methods: \(i = I e^{j\varphi}\) and \(i = I \cos\varphi + j I \sin\varphi\).
Where \(I > 0\), \(\varphi \in [-\pi, \pi]\), thus \(i\) can represent a complex number, and \(I\) represents a sinusoidal quantity.
Page 35
The note discusses complex numbers and their operations in the complex plane. It explains that complex numbers can be uniquely represented in the complex plane and that the phase of a complex number does not affect its operation. The note covers the following points:
1. **Operations of Complex Numbers:**
- **Addition and Subtraction:** Follows the rules of complex number operations.
- **Multiplication:** The product of two complex numbers in polar form is the product of their magnitudes and the sum of their phases.
- **Division:** The quotient of two complex numbers in polar form is the quotient of their magnitudes and the difference of their phases.
- **Multiplication Example:** $z_1 \cdot z_2 = z_1 < \phi_1 \cdot z_2 < \phi_2 = z_1 z_2 < (\phi_1 + \phi_2)$.
- **Division Example:** $z_1 / z_2 = z_1 < \phi_1 / z_2 < \phi_2 = z_1 / z_2 < (\phi_1 - \phi_2)$.
- **Multiplication Formula:** $z_1 \cdot z_2 = (z_1 \cos \phi_1 + j z_1 \sin \phi_1) \cdot (z_2 \cos \phi_2 + j z_2 \sin \phi_2)$.
- **Division Formula:** $z_1 / z_2 = z_1 / z_2 \cdot (\cos \phi_1 + j \sin \phi_1) \cdot (\cos \phi_2 - j \sin \phi_2) / 1$.
- **Special Cases:** $j \cdot z < \phi = 1 \cdot z < \phi = z < (\phi + 90^\circ)$, $-j \cdot z < \phi = 1 \cdot z < \phi = z < (\phi - 90^\circ)$, $-1 < \phi = 1 \cdot z < \phi = z < (\phi + 180^\circ)$.
2. **Derivative:**
- The derivative of a complex function is the imaginary part of the derivative of the complex function.
- $\frac{d z}{dt} = \frac{d}{dt} \text{Im}[\sqrt{2} i e^{jwt}] = \text{Im}[\frac{d}{dt} (\sqrt{2} i e^{jwt})] = \text{Im}[\sqrt{2} j \omega i e^{jwt}]$.
- $\text{Im}[\sqrt{2} (\omega i) e^{j(\omega t + 90^\circ)}]$.
3. **Integral:**
- The integral of a complex function is the imaginary part of the integral of the complex function.
- $\int i dt = \text{Im}[\int \sqrt{2} i e^{jwt} dt] = \text{Im}[\int \frac{1}{j \omega} \cdot i e^{jwt}]$.
- $\text{Im}[\int \frac{1}{j \omega} (\omega i) e^{j(\omega t - 90^\circ)}]$.
4. **Modulus:**
- The modulus of the product of two complex numbers is the product of their moduli.
- $|a + j b| = \sqrt{a^2 + b^2}$.
- $|z_1 z_2| = |z_1| |z_2|$.
- $|z_1 / z_2| = \frac{|z_1|}{|z_2|}$.
- $|z_1 z_2| = \sqrt{a^2 + b^2} \cdot \sqrt{c^2 + d^2} = |a + j b| \cdot |c + j d|$.
- $|a + j b| = \frac{\sqrt{a^2 + b^2}}{\sqrt{c^2 + d^2}} = \frac{|a + j b|}{\sqrt{c^2 + d^2}}$.
- $|a + j b| = \frac{\sqrt{a^2 + b^2}}{\sqrt{c^2 + d^2}} = \frac{|a + j b|}{\sqrt{c^2 + d^2}}$.
- $|a + j b| = \frac{\sqrt{a^2 + b^2}}{\sqrt{c^2 + d^2}} = \frac{|a + j b|}{\sqrt{c^2 + d^2}}$.
- $|a + j b| = \frac{\sqrt{a^2 + b^2}}{\sqrt{c^2 + d^2}} = \frac{|a + j b|}{\sqrt{c^2 + d^2}}$.
- $|a + j b| = \frac{\sqrt{a^2 + b^2}}{\sqrt{c^2 + d^2}} = \frac{|a + j b|}{\sqrt{c^2 + d^2}}$.
- $|a + j b| = \frac{\sqrt{a^2 + b^2}}{\sqrt{c^2 + d^2}} = \frac{|a + j b|}{\sqrt{c^2 + d^2}}$.
- $|a + j b| = \frac{\sqrt{a^2 + b^2}}{\sqrt{c^2 + d^2}} = \frac{|a + j b|}{\sqrt{c^2 + d^2}}$.
- $|a + j b| = \frac{\sqrt{a^2 + b^2}}{\sqrt{c^2 + d^2}} = \frac{|a + j b|}{\sqrt{c^2 + d^2}}$.
- $|a + j b| = \frac{\sqrt{a^2 + b^2}}{\sqrt{c^2 + d^2}} = \frac{|a + j b|}{\sqrt{c^2 + d^2}}$.
- $|a + j b| = \frac{\sqrt{a^2 + b^2}}{\sqrt{c^2 + d^2}} = \frac{|a + j b|}{\sqrt{c^2 + d^2}}$.
- $|a + j b| = \frac{\sqrt{a^2 + b^2}}{\sqrt{c^2 + d^2}} = \frac{|a + j b|}{\sqrt{c^2 + d^2}}$.
- $|a + j b| = \frac{\
Page 36
Component Constraints
**Resistance:**
$$ u = R i $$
**Capacitor:**
$$ u = \sqrt{2} U \sin(\omega t + \varphi) $$
$$ i = C \frac{du}{dt} = \sqrt{2} \omega C U \sin(\omega t + \varphi + 90^\circ) $$
$$ \therefore i = j \omega C u, u = j \left( -\frac{1}{\omega C} \right) i $$
$$ X_{\text{capacitive}} = -\frac{1}{\omega C}, B_{\text{capacitive}} = \omega C $$
**Inductor:**
$$ i = \sqrt{2} I \sin(\omega t + \varphi) $$
$$ \therefore u = L \frac{di}{dt} = \sqrt{2} \omega L I \sin(\omega t + \varphi + 90^\circ) $$
$$ \therefore i = j \omega L i, i = j \left( \frac{1}{\omega L} \right) u $$
$$ X_{\text{inductive}} = \omega L, B_{\text{inductive}} = -\frac{1}{\omega L} $$
**From the above derivation, it can be concluded that the voltage across the ends of the circuit is:**
$$ Z = \frac{U}{I} = \frac{U}{I} = (\varphi_u - \varphi_i) = |Z| \angle \varphi = R + jX $$
$$ R \text{ is resistance, } X \text{ is reactance } \in \{X, X_C\}, Z \text{ is impedance, in a DC circuit, } R \text{ is equivalent to resistance. } $$
**Herein, in mathematics, DC linear resistive circuits and AC steady-state linear circuits are completely equivalent. Kirchhoff's laws derived in AC steady-state can be expressed in complex form and are applicable.**
Power
**General:**
$$ P(t) = \sqrt{2} U \sin(\omega t + \varphi_u) \times \sqrt{2} I \sin(\omega t + \varphi_i) $$
$$ = UI - 2 \sin(\omega t + \varphi_u) \sin(\omega t + \varphi_i) $$
$$ = UI \cos(\varphi_u - \varphi_i) - UI \cos(2\omega t + \varphi_u + \varphi_i) $$
$$ = UI \cos \varphi - UI \cos(2\omega t + \varphi_u + \varphi_i) $$
**Average power:**
$$ P = \frac{1}{T} \int_0^T P(t) dt = UI \cos \varphi $$
**This is the power consumed by the resistor, also known as active power.**
**Power meter:**
$$ \Delta \text{measured voltage effective value, } \varphi = \varphi_u - \varphi_i \text{ is the phase angle. } $$
Page 37
No.
Date
\textbf{Reactive Power}: \( Q = UI \sin \phi \) (var)
This represents the power exchanged between the circuit and the external circuit, caused by capacitors and inductors.
\textbf{Apparent Power}: \( S = UI \) V·A
When \( R \) is constant, \( \phi \in [-\frac{\pi}{2}, \frac{\pi}{2}] \).
\begin{cases}
\text{Inductive: } \phi > 0, \text{ lagging power factor} \\
\text{Capacitive: } \phi < 0, \text{ leading power factor}
\end{cases}
In practical electrical equipment, many are inductive loads. To improve the power factor, capacitors are connected in parallel to the inductive load to increase the overall power factor and improve power utilization.
\[
\begin{aligned}
&\text{Parallel capacitor does not affect active power: } UI \cos \phi_1 = UI \cos \phi_2 = P. \\
&\therefore I_2 = \frac{P}{U \cos \phi_1}, \quad I = \frac{P}{U \cos \phi_2} \\
&\therefore I_c = I - I_2 = I \cos \phi_2 + j I \sin \phi_2 - I_2 \cos \phi_1 - j I_2 \sin \phi_1 \\
&= I \cos \phi_2 - I_2 \cos \phi_1 + j (I \sin \phi_2 - I_2 \sin \phi_1) \\
&\therefore I_c = \sqrt{(I \cos \phi_2 - I_2 \cos \phi_1)^2 + (I \sin \phi_2 - I_2 \sin \phi_1)^2} \\
&= \sqrt{I^2 + I_2^2 - 2 I I_2 \cos (\phi_2 - \phi_1)} \\
&= \frac{P}{U} \sqrt{\frac{1}{\cos \phi_1} + \frac{1}{\cos \phi_2} - \frac{2 \cos (\phi_2 - \phi_1)}{\cos \phi_1 \cos \phi_2}} \\
&= \frac{P}{U} (\tan \phi_1 - \tan \phi_2) = \omega C U \\
&\therefore C = \frac{P}{\omega U^2} (\tan \phi_1 - \tan \phi_2)
\end{aligned}
\]
\textbf{Summary}: Power can be expressed as a complex number \( S = UI \) where \( I = I \cos \phi + j I \sin \phi \). Thus, \( S = UI \cos (\phi_1 - \phi_2) + j UI \sin (\phi_1 - \phi_2) = UI \cos \phi + j UI \sin \phi = P + j Q \) V·A
Page 38
Maximum Power Transfer: Load impedance from a given power supply to obtain maximum real power condition.
$$ i = \frac{U_S}{Z_S + Z} = \frac{U_S}{(R_S + R) + j(X_S + X)} \quad \therefore Z = \sqrt{(R_S + R)^2 + (X_S + X)^2} $$
$$ \therefore P = I^2 R = \frac{U_S^2 R}{(R + R_S)^2 + (X + X_S)^2} \quad \text{Variables are } R \text{ and } X, R > 0. $$
1) Only Z's imaginary part can vary.
$$ \text{When } X + X_S = 0 \text{, i.e., } X = -X_S \text{, } P_{\max} = \frac{U_S^2 R}{(R + R_S)^2}. $$
2) R and X can vary.
$$ \because P > 0, \therefore X + X_S = 0 \text{ when } P \text{ can reach maximum, } \frac{\partial}{\partial R} \left[ \frac{U_S^2 R}{(R + R_S)^2} \right] = 0 \quad \therefore R = R_S $$
$$ \therefore Z = Z_S^* \text{ (conjugate)} $$
$$ \therefore P_{\max} = \frac{U_S^2}{4R_S}, \quad \eta = 50\%. $$
3) Z's magnitude can vary, but the resistance remains constant.
$$ P = \frac{U_S^2 |Z| \cos \phi}{(|Z| \cos \phi + R_S)^2 + (|Z| \sin \phi + X_S)^2} = \frac{U_S^2 \cos \phi |Z|}{|Z|^2 + 2(R_S \cos \phi + X_S \sin \phi) |Z| + R_S^2 + X_S^2} $$
$$ = \frac{U_S^2 \cos \phi}{|Z| + \frac{R_S^2 + X_S^2}{|Z|} + 2(R_S \cos \phi + X_S \sin \phi)} \leq \frac{U_S^2 \cos \phi}{2\sqrt{R_S^2 + X_S^2} + 2(R_S \cos \phi + X_S \sin \phi)} $$
$$ \text{At this time, } |Z| = \sqrt{R_S^2 + X_S^2}. $$
Example - Transformer.
1) Use the right-hand rule to determine the direction of the magnetic field produced by the current and the interaction between them.
2) Determine the mutual inductance and whether the magnetic fluxes are mutually reinforcing. Need to determine the two ends of the two coils. If the currents are in the same direction, the voltage in the other coil is in the opposite direction. If the currents are in opposite directions, the voltage in the other coil is in the same direction. The size is M * di/dt. The opposite is also true.
3) The coupling coefficient k: The strength of the interaction between two mutually inductive coils. $$ k = \frac{M}{\sqrt{L_1 L_2}}. $$
$$ \therefore k^2 = \frac{M^2}{L_1 L_2} = \frac{M^2 \phi_1 \phi_2}{L_1 L_2} = \frac{N_1 \phi_1 N_2 \phi_2}{L_1 L_2} = \frac{\phi_1 \phi_2}{N_1 N_2}. $$
Page 39
The mutual inductance between two coils is defined as the ratio of the mutual flux linkage to the current in the other coil. The mutual inductance \( M \) is given by the formula:
\[ M = \frac{\phi_1}{i_2} = \frac{\phi_2}{i_1} \]
The mutual inductance \( M \) is always positive and can be expressed as:
\[ M = \sqrt{L_1 L_2} \]
For two coils with mutual inductance \( M \), the total inductance \( L_{eq} \) can be calculated as follows:
1. **Series Connection (Series Connection)**
\[ L_{eq} = L_1 + L_2 + 2M \]
2. **Series Connection (Series Connection)**
\[ L_{eq} = L_1 + L_2 - 2M \]
3. **Parallel Connection (Parallel Connection)**
\[ L_{eq} = \frac{L_1 L_2 - M^2}{L_1 + L_2 - 2M} \]
4. **Parallel Connection (Parallel Connection)**
\[ L_{eq} = \frac{L_1 L_2 - M^2}{L_1 + L_2 - 2M} \]
The mutual inductance \( M \) can be calculated as:
\[ M = \frac{L_{eq1} - L_{eq2}}{4} \]
The total inductance \( L_{eq} \) can be expressed as:
\[ L_{eq} = \frac{L_1 L_2 - M^2}{L_1 + L_2 - 2M} \]
Page 40
The page contains a detailed analysis of a transformer circuit, specifically focusing on the空心变压器 (air-core transformer). The text discusses the circuit's behavior in the frequency domain, using complex impedances and mutual inductance. The formulas derive the currents and voltages in the transformer's windings, considering resistances, inductances, and mutual inductance. The page also includes the equivalent circuits for the transformer's primary and secondary sides, represented as
and
, respectively. The final section presents the T-shaped equivalent circuit for the transformer, which is represented as
. The text is technical and assumes knowledge of electrical engineering concepts.
Page 41
Also, through adding a common terminal wire to the coupled branches, we can obtain a T-shaped equivalent circuit.
$$
\begin{aligned}
& \therefore \left\{\begin{array}{l}
R_{1} i_{1}+j \omega\left(R_{1}-M\right) i_{1}+j \omega\left(Z_{2}+i_{2}\right) M=u_{1} \\
j \omega\left(Z_{2}+i_{2}\right) M+\left(R_{2}+Z_{2}\right) i_{2}+j \omega\left(Z_{2}-M\right) i_{2}=0 .
\end{array}\right.
\end{aligned}
$$
Example 2: Coupled Transformer. (k=1, M=√L1L2, R1=R2=0)
$$
\begin{aligned}
& \left\{\begin{array}{l}
u_{1}=j \omega L_{1} i_{1}+j \omega \sqrt{L_{1} L_{2}} i_{2} \\
u_{2}=j \omega \sqrt{L_{2}} i_{1}+j \omega L_{2} i_{2}
\end{array}\right. \Rightarrow \left\{\begin{array}{l}
\frac{u_{1}}{u_{2}}=\sqrt{\frac{L_{1}}{L_{2}}} \triangleq n \\
i_{1}=\frac{u_{1}}{j \omega L_{1}}-\frac{1}{n} i_{2}
\end{array}\right.
\end{aligned}
$$
Example 3: Ideal Transformer. (L1, L2, M→∞, √L1/L2=n, on full coupling)
$$
\begin{aligned}
& \left\{\begin{array}{l}
u_{1}=n u_{2} \\
i_{1}=-\frac{1}{n} i_{2}
\end{array}\right. \sim \frac{u_{1}}{u_{2}} \sim P=u_{1} i_{1}+u_{2} i_{2}=n u_{2}+\left(\frac{1}{n} i_{2}\right)+u_{2} i_{2}=0 .
\end{aligned}
$$
$$
\sim T=\left[\begin{array}{cc}
n & 0 \\
0 & \frac{1}{n}
\end{array}\right] \text { 互易. }
$$
The ideal transformer can be seen as a voltage-controlled voltage source. The control quantity u1 is the controlled quantity u2.
Example 4: Intermediate Tap Transformer
$$
\begin{aligned}
& u_{1}: \text { Full-wave rectifier; phase shifter; two-phase conversion. }
\end{aligned}
$$
Page 42
2. Analysis Extension - Non-Periodic Steady-State
1. Decomposition of Periodic Non-Periodic Signals into Components
$$ f(t) = a_0 + \sum_{k=1}^{\infty} [a_k \cos(k\omega_1 t) + b_k \sin(k\omega_1 t)] $$
$$ = a_0 + \sum_{k=1}^{\infty} c_k \sin(k\omega_1 t + \phi_k) $$
$$ = a_0 + c_1 \sin(\omega_1 t + \phi_1) + \sum_{k=2}^{\infty} c_k \sin(k\omega_1 t + \phi_k) $$
$$ \downarrow \text{DC Component (Average Value)} \quad \downarrow \text{Fundamental Component} (\omega_1 = \frac{2\pi}{T}) \quad \downarrow \text{Higher Harmonics} (k \geq 2), \text{Decay}
2. Effective Value and Average (Effective) Power Calculation
$$ i = I_0 + \sum_{k=1}^{\infty} I_km \sin(k\omega_1 t + \phi_k) \quad (\omega_1 = \frac{2\pi}{T}) $$
$$ \therefore I = \sqrt{\frac{1}{T} \int_0^T [I_0 + \sum_{k=1}^{\infty} I_km \sin(k\omega_1 t + \phi_k)]^2 dt} $$
$$ \text{Since} \quad \frac{1}{T} \int_0^T I_0^2 dt = I_0^2, \quad \frac{1}{T} \int_0^T I_km^2 \sin^2(k\omega_1 t + \phi_k) dt = \frac{2I_km^2}{2} = I_k^2 $$
$$ \frac{1}{T} \int_0^T 2I_0 I_km \sin(k\omega_1 t + \phi_k) dt = \frac{1}{T} \int_0^T 2I_km \sin(k\omega_1 t + \phi_k) \cdot I_km \sin(k\omega_1 t + \phi_k) dt $$
$$ = 0 $$
$$ \therefore I = \sqrt{I_0^2 + \sum_{k=1}^{\infty} I_k^2}, \quad I_0 \text{ is the DC component, } I_k \text{ is the AC effective value, and the AC component is zero.} $$
3. Steady-State Response to Periodic Non-Periodic Excitation
$$ p = u_i = [U_0 + \sum_{k=1}^{\infty} \sqrt{2}U_k \sin(k\omega_1 t + \phi_{uk})] \cdot [I_0 + \sum_{k=1}^{\infty} \sqrt{2}I_k \sin(k\omega_1 t + \phi_{ik})] $$
$$ \therefore p = \frac{1}{T} \int_0^T p dt = U_0 I_0 + \sum_{k=1}^{\infty} U_k I_k \cos(\phi_{uk} - \phi_{ik}) $$
$$ = U_0 I_0 + \sum_{k=1}^{\infty} U_k I_k \cos\phi_k, \quad U_0 I_0 \text{ is the DC power, } U_k I_k \cos\phi_k \text{ is the AC component.} $$
4. Steady-State Response to Periodic Non-Periodic Excitation
$$ \text{The response of each component (DC, AC components of different frequencies) is calculated separately. The AC component is zero.} $$
$$ \text{The total steady-state response is obtained by summing the responses of each component.} $$
$$ \text{Note that at a certain frequency, the circuit may produce a steady-state response due to the excitation.} $$
Page 43
3. Frequency response → oscillation → filter.
For dynamic components, the impedance (amplitude, phase) at the output is a function of frequency.
Example: MOSFET parasitic capacitance's impact on transient and steady-state response.
\begin{equation}
U_{in} \xrightarrow{G_1} D \xrightarrow{G_2} U_{out}
\end{equation}
\begin{tabular}{|c|c|}
\hline
\textbf{Transient response (rectangular pulse excitation)} & \textbf{Steady-state response (small signal excitation)} \\
\hline
\begin{equation}
\Delta U_{in} = 0
\end{equation} & \begin{equation}
\Delta U_{in} = \Delta U_{GS1} G_1
\end{equation} \\
\begin{equation}
U_{in1} = U_{in2}
\end{equation} & \begin{equation}
U_{in1} = U_{in2}
\end{equation} \\
\begin{equation}
R_1 C_{as1} \frac{dU_{in1}}{dt} = 0
\end{equation} & \begin{equation}
R_1 C_{as1} \frac{dU_{in1}}{dt} = -\Delta U_{GS1} G_1
\end{equation} \\
\begin{equation}
U_{in1}(0^+) = U_{in}
\end{equation} & \begin{equation}
U_{in1}(0^+) = 0
\end{equation} \\
\begin{equation}
U_{in1}(\infty) \approx 0
\end{equation} & \begin{equation}
U_{in1}(\infty) = U_{in}
\end{equation} \\
\begin{equation}
\tau = R_1 C_{as1}
\end{equation} & \begin{equation}
\tau = R_1 C_{as1}
\end{equation} \\
\begin{equation}
x R_1 C_{as1}
\end{equation} & \begin{equation}
x R_1 C_{as1}
\end{equation} \\
\begin{equation}
U_{in1}(t) \approx U_{in} e^{-\frac{t}{\tau}}
\end{equation} & \begin{equation}
U_{in1}(t) \approx U_{in} e^{-\frac{t}{\tau}}
\end{equation} \\
\begin{equation}
U_{in1}(t) = U_{in1} e^{-\frac{t}{\tau}}
\end{equation} & \begin{equation}
U_{in1}(t) = U_{in1} e^{-\frac{t}{\tau}}
\end{equation} \\
\begin{equation}
t_{rise} = \tau \ln \left( \frac{U_{in1}(t) - U_{in1}(0^+)}{U_{in1}(t) - U_{in1}(\infty)} \right)
\end{equation} & \begin{equation}
t_{rise} = \tau \ln \left( \frac{U_{in1}(t) - U_{in1}(0^+)}{U_{in1}(t) - U_{in1}(\infty)} \right)
\end{equation} \\
\hline
\end{tabular}
\begin{equation}
H = \frac{\Delta U_{in}}{\Delta U_{GS1}} = \frac{\Delta U_{DS1}}{\Delta U_{GS1}}
\end{equation}
\begin{equation}
H = -g_m R_L = -\frac{\Delta U_{DS1}}{\Delta U_{GS1}}
\end{equation}
\begin{equation}
H = g_m R_L \cdot \frac{R_L}{1 + j \omega C_{as2} R_L} \cdot \Delta \dot{U}_{DS1}
\end{equation}
\begin{equation}
H = \frac{g_m^2 R_L^2}{1 + j \omega C_{as2} R_L} \cdot \Delta \dot{U}_{DS1}
\end{equation}
\begin{equation}
H = \frac{g_m^2 R_L^2}{\sqrt{1 + (\omega C_{as2} R_L)^2}} \cdot \Delta \dot{U}_{DS1}
\end{equation}
Page 44
Resonance Classification, Conditions, Equivalent Impedance, and Quality Factor
# Network Function H(ω) = R / Z
R: The excitation voltage in the circuit produces a stable steady-state response.
# Series Resonance (Voltage Resonance):
Z = R + j(ωL - 1/ωC), H(ω) = Uc / Us = R / (R + jωL + 1/jωC)
∴ |Z| = √(R² + (ωL - 1/ωC)²), |H(ω)| = R / √(R² + (ωL - 1/ωC)²)
φ(ω) = arctan(ωL - 1/ωC) - arctan(R) = arctan(ωL - 1/ωC)
When ω₀ = √(1/LC), |Z| is minimum, |H(ω)| is maximum, φ(ω) is zero, Us is in phase.
I(ω₀) = Ic / R, Ic(∞) = Is
# Parallel Resonance (Current Resonance):
Y = G + j(ωC - 1/ωL), H(ω) = Ic / Is = 1 / (G + jωC + 1/jωL) = jωL / (1 - ω²LCjωL)
∴ |Y| = √(G² + (ωC - 1/ωL)²), |H(ω)| = 1 / √(G² + (ωC - 1/ωL)²)
φ(ω) = arctan[(ωC - 1/ωL) / G]
When ω₀ = √(1/LC), |Y| is minimum, |H(ω)| is maximum, φ(ω) is zero, Us is in phase.
Ic(ω₀) = Is / G, Ic(∞) = Is
# Parallel Resonance:
When Z → ∞; series resonance when Z → 0. So the parallel resonance part can be considered as an open circuit, while the series resonance part is a short circuit. And the series resonance frequency is lower than the parallel resonance frequency (2πf₀ < 2πf₀).
# Quality Factor:
1) The amplification factor of the output power during resonance.
2) The circuit's corresponding damping coefficient α = ω₀ / 2Q.
3) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
4) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
5) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
6) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
7) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
8) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
9) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
10) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
11) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
12) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
13) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
14) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
15) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
16) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
17) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
18) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
19) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
20) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
21) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
22) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
23) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
24) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
25) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
26) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
27) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
28) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
29) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
30) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
31) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
32) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
33) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
34) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
35) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
36) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
37) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at ω₀.
38) The ratio of the circuit's energy consumption per period during resonance to the energy stored in the circuit at
Page 45
2. Low-pass filter.
$$H(\omega) = \frac{U_C}{U_S} = \frac{\frac{1}{j\omega C}}{R + \frac{1}{j\omega C}} = \frac{1}{1 + j\omega RC}$$
$$|H(\omega)| = \frac{1}{\sqrt{1 + (\omega RC)^2}}$$
$$\theta(\omega) = \arctan\left(\frac{1}{\omega RC}\right) - \arctan\left(\frac{1}{\omega R}\right)$$
$$\omega_C = \frac{1}{RC} = \frac{1}{T}$$
The range from 0 to ωC is called the passband.
ωC is called the cutoff frequency (or the power frequency), and in engineering, this is the boundary of the filter's passband and stopband.
3. High-pass filter.
$$H(\omega) = \frac{U_C}{U_S} = \frac{\frac{1}{j\omega L}}{R + \frac{1}{j\omega L}} = \frac{1}{1 - j\frac{\omega R}{L}}$$
$$|H(\omega)| = \frac{1}{\sqrt{1 + \left(\frac{\omega R}{L}\right)^2}}$$
When |H(ω)| = $\frac{\sqrt{2}}{2}$, ωL = $\frac{R}{L}$.
4. Band-pass filter, band-reject filter.
The cutoff frequency of the high-pass filter is less than the cutoff frequency of the low-pass filter, i.e., $\frac{1}{RC_1} < \frac{1}{RC_2}$ is the passband, and $\frac{1}{RC_1} > \frac{1}{RC_2}$ is the stopband.
$$H(\omega) = \frac{U_C}{U_S} = \frac{U_C}{U_S} \times \frac{U_S}{U_I} = \frac{j\omega C_2 R_2}{1 + j\omega C_1 R_2} \times \frac{1}{1 + j\omega C_1 R_1} = \frac{j\omega C_2 R_2}{1 - \omega^2 R_2 R_1 C_1 C_2 + j\omega (C_1 R_1 + C_2 R_2)}$$
Page 46
No.
Data
2) RLC resonant circuit forms a band-pass filter
$$H(\omega) = \frac{U_R}{U_S} = \frac{R}{R+j\omega L+\frac{1}{j\omega C}} = \frac{j\omega CR}{1-\omega^2LC+j\omega CR}$$
$$|H(\omega)| = \frac{R}{\sqrt{R^2+(\omega L-\frac{1}{\omega C})^2}}. \quad \varphi(\omega) = \arctan \frac{\omega L-\frac{1}{\omega C}}{R}$$
$$\dot{I}(\omega) = \frac{\dot{U}}{R+j(\omega L-\frac{1}{\omega C})} = \frac{\dot{I}(\omega_0)}{1+j(\frac{\omega L}{R}-\frac{1}{\omega CR})}$$
$$\dot{I}(\omega) = \frac{\dot{I}(\omega_0)}{\sqrt{1+(\frac{\omega L}{R}-\frac{1}{\omega CR})^2}}, \quad I(\omega) = \frac{1}{\sqrt{1+(\frac{\omega L}{R}\cdot\frac{\omega}{\omega_0}-\frac{1}{\omega_0CR}\cdot\frac{\omega}{\omega})^2}}, \quad \frac{Z(\omega)}{Z(\omega_0)} = \frac{1}{\sqrt{1+Q^2(\eta-\eta_1)^2}}$$
$$\therefore Q = \frac{1}{\eta_2-\eta_1} = \frac{\omega_0}{\omega_2-\omega_1}. \quad Q \text{越大, 通频带越窄, 曲线在谐振频率附近尖锐}$$
3) Band-stop filter
High-pass cutoff frequency is greater than low-pass cutoff frequency, i.e.
$$\frac{1}{R_1C_1} > \frac{1}{R_2C_2} \text{ when } (\frac{1}{R_1C_1}-\frac{1}{R_2C_2}) \text{ is disconnected.}$$
4) RLC resonant circuit forms a band-stop filter
$$U_{Z_1} = \frac{Z_1}{Z_1+R+j\omega L+\frac{1}{j\omega C}} \cdot I_S$$
$$U_{Z_1} = \frac{\sqrt{(R+j(\frac{\omega_0}{\omega}-\omega L))^2+(jR\omega C+\omega R_L L-\frac{R_L^2}{\omega C})^2}}{(R+j(\frac{\omega_0}{\omega}-\omega L))^2+(jR\omega C+\omega R_L L-\frac{R_L^2}{\omega C})^2} \cdot I_S$$
Page 47
5. Full-wave bridge rectifier:
$$U_{C} = \frac{1}{j\omega C}U_{S} = \frac{1}{1+j\omega CR_{0}}U_{S}$$
$$U_{AB} = U_{S} - U_{C} = \frac{1}{2}U_{S} - \frac{1}{1+j\omega CR_{0}}U_{S} = \frac{j\omega CR_{0} - 1}{2(1+j\omega CR_{0})}U_{S}$$
$$\therefore H(\omega) = \frac{U_{AB}}{U_{S}} = \frac{j\omega CR_{0} - 1}{2(1+j\omega CR_{0})}$$
$$|H(\omega)| = 0.5, \varphi(\omega) = \pi - 2\arctan(\omega CR_{0})$$
6. Full-wave bridge rectifier:
$$U_{AB} + U_{1} + iR = 0$$
$$U_{AB} = U_{S} + i\frac{1}{j\omega C}$$
$$\therefore H(\omega) = \frac{U_{AB}}{U_{1}} = \frac{1 + \frac{i}{j\omega C}}{1 - \frac{i}{\omega CR}}$$
$$\therefore |H(\omega)| = 1, \varphi(\omega) = \arctan(2\omega CR)$$
4. Three-phase circuit: three-phase power source, three-phase load, three-phase transmission lines.
1. Symmetrical three-phase circuit:
$$U_{A} = \sqrt{2}U_{S}\sin(\omega t + \varphi)$$
$$U_{B} = \sqrt{2}U_{S}\sin(\omega t + \varphi - 120^\circ)$$
$$U_{C} = \sqrt{2}U_{S}\sin(\omega t + \varphi + 120^\circ)$$
$$U_{A} + U_{B} + U_{C} = i_{A} + i_{B} + i_{C} = 0$$
$$U_{AB} = U_{A} - U_{B} - 120^\circ = \sqrt{3}U_{A} \angle 30^\circ$$
$$i_{A} + i_{B} + i_{C} = 0 \therefore i_{N}$$
$$i_{A} = i_{AB} - i_{CA} = \sqrt{3}i_{AB} \angle -30^\circ$$
$$U_{AB} = U_{A}, U_{BC} = U_{B}, U_{CA} = U_{C}$$
Page 48
For the delta connection's impedance, it can be converted into a star connection. When the power supply is a star connection, the single-phase method can be used for analysis.
(2) Unbalanced three-phase circuit.
In actual power systems, the power supply is not balanced, and the load is not balanced.
The midpoint exists when U_{1}=U_{2}=U_{3}.
The midpoint does not exist when the midpoint voltage U_{1}=U_{2}=U_{3}.
(3) Three-phase circuit power.
Single-phase active power: U_{p}I_{p}cosφ=P_{p} U_{p}, I_{p} are phase voltage, phase current
For star connection: U_{p}=\frac{U_{1}}{\sqrt{3}}, I_{p}=I_{1}
For delta connection: U_{p}=U_{1}, I_{p}=\frac{I_{1}}{\sqrt{3}}
∴ Three-phase total power P=3U_{p}I_{p}cosφ=\sqrt{3}U_{1}I_{1}cosφ.
Reactive power Q=3U_{p}I_{p}sinφ=\sqrt{3}U_{1}I_{1}sinφ
Apparent power S=3U_{p}I_{p}=\sqrt{3}U_{1}I_{1}
Assuming U_{AN}=\sqrt{2}U_{p}sinwt, I_{A}=\sqrt{2}I_{p}sin(wt+φ), the three-phase instantaneous power is
P_{A}=U_{AN}I_{A}=\sqrt{2}U_{p}sinwt\cdot\sqrt{2}I_{p}sin(wt-φ)
=U_{p}I_{p}[cosφ-cos(2wt-φ-120°)]
P_{B}=U_{AN}I_{B}=\sqrt{2}U_{p}sin(wt-120°)\cdot\sqrt{2}I_{p}sin(wt-φ-120°)
=U_{p}I_{p}[cosφ-cos(2wt-φ+120°)]
P_{C}=U_{AN}I_{C}=\sqrt{2}U_{p}sin(wt+120°)\cdot\sqrt{2}I_{p}sin(wt-φ+120°)
=U_{p}I_{p}[cosφ-cos(2wt-φ+240°)]
P=P_{A}+P_{B}+P_{C}=3U_{p}I_{p}cosφ. ⇒ The motor rotates smoothly.
Page 49
Three-phase four-wire system:
$$W = W_1 + W_2 + W_3$$
Three-phase three-wire system:
$$i_A + i_B + i_C = 0$$
$$\therefore u_C = -i_A - i_B$$
$$\therefore P = u_A i_A + u_B i_B + u_C i_C$$
$$= u_A i_A + u_B i_B + u_C (-i_A - i_B) = (u_A - u_B) i_A + (u_B - u_C) i_B$$
$$= u_A i_A + u_B i_B$$
$$\therefore W = \overline{P} = u_A i_A \cos \varphi_1 + u_B i_B \cos \varphi_2$$
Page 50
Semiconductor Device Fundamentals
# 1. Semiconductors: Si, Ge, GaAs...
- **Intrinsic Semiconductors:**
- **(1) Perfectly Clean, Structurally Complete Semiconductors.** (Impurities)
- **(2) At T=0K, in the absence of external influences, valence electrons are bound in covalent bonds.)
- **(3) At elevated temperatures or under light illumination, valence electrons can split into free electrons and holes. The number of holes equals the number of split-off electrons. This is known as intrinsic excitation.**
- **(4) Free electrons continuously escape and fill the holes, forming a current that flows in the opposite direction of electron movement.**
- **n_i = p_i** (Intrinsic semiconductor electron concentration = hole concentration).
- **(5) At elevated temperatures, intrinsic excitation increases, and the number of carriers increases. With increasing concentration, electron-hole pairs are produced and recombine, reaching a dynamic equilibrium.**
- **n_i = p_i = A * T^(3/2) * e^(-E_g / (2 * k * T))**
# Doped Semiconductors:
- **N-Type:**
- **Doping with pentavalent elements:** P, As, Sb.
- **At room temperature, the intrinsic carrier concentration is negligible.**
- **Majority carriers: Free electrons.**
- **Minority carriers: Holes.**
- **n_0 = N_D + p_0 ≈ N_D**
- **P-Type:**
- **Doping with trivalent elements:** B, Al, In.
- **At room temperature, the intrinsic carrier concentration is negligible.**
- **Majority carriers: Holes.**
- **Minority carriers: Free electrons.**
- **p_0 = N_A + n_0 ≈ N_A.**
- **At room temperature, the intrinsic carrier concentration is negligible.**
- **n_0 p_0 = n_i^2**
- **The minority carrier concentration is highly sensitive to temperature, while the majority carrier concentration is less sensitive. At a certain temperature, the minority carrier concentration can be close to the majority carrier concentration, and the semiconductor device may not function properly.**
Page 51
2. Carrier Mobility
The drift velocity of free electrons is \( v_n = -\mu_n E \), where \(\mu_n\) is the electron mobility.
The drift velocity of holes is \( v_p = \mu_p E \), where \(\mu_p\) is the hole mobility.
The carrier concentration increases, mobility decreases; temperature increases, mobility decreases; \(\mu_n > \mu_p\).
\( I = I_n + I_p = qS(-n v_n + p v_p) = qS(n \mu_n E + p \mu_p E) \)
\( = q \cdot \frac{S \cdot V}{L} (n \mu_n + p \mu_p) \)
\( q = 1.6 \times 10^{-19} C \)
\(\therefore R = \frac{V}{I} = \frac{p \frac{L}{S}}{q \frac{1}{S} (n \mu_n + p \mu_p)} \)
\(\therefore \sigma = q (n \mu_n + p \mu_p) \)
For doped semiconductors, \(\sigma\) mainly depends on the carrier concentration, so the temperature coefficient is negative.
For intrinsic semiconductors, as temperature increases, mobility decreases, carrier concentration increases, conductivity increases.
3. Carrier Diffusion
In a certain region of the semiconductor, when illuminated or injected carriers, the carrier concentration increases.
\(\rightarrow\) carrier diffusion \(\rightarrow\) diffusion current
\(\rightarrow\) \( I_n = q S D_n \frac{d n(x)}{dx} \)
\(\frac{D_p}{\mu_p} = \frac{D_n}{\mu_n} = \frac{kT}{q} \)
3. PN Junction
Positive and negative carriers meet, \( p \) region has more holes than \( n \) region has electrons.
\(\rightarrow\) holes diffuse from \( p \) to \( n \), electrons diffuse from \( n \) to \( p \), at the interface.
\( p \) region has fewer electrons than \( n \) region has holes.
\(\rightarrow\) holes and electrons recombine at the interface \(\rightarrow\) fixed negative ions in \( p \) region, fixed positive ions in \( n \) region.
\(\rightarrow\) space charge region forms at the interface, positive and negative charges separate \(\rightarrow\) internal built-in electric field forms, which prevents further diffusion of carriers.
Page 52
The minority carriers (electrons) in the P region diffuse toward the N region. Due to the concentration difference, the diffusion motion and the drift motion caused by the internal electric field reach a dynamic equilibrium, resulting in zero net current and zero net charge in the space charge region. The built-in electric field E is shown in the figure. The figure shows the low resistance region, high resistance region, low resistance region, potential barrier, and depletion layer. The depletion layer is also referred to as the depletion region. The contact potential difference is given by Vφ = kT/q * ln(NA/ND). The temperature voltage quantity is Vt = kT/q ≈ 26mV (at 300K). Vφ has a negative temperature coefficient. The potential barrier width is W0 = Wn + Wp = √(2ε/ε) * Vφ * (NA + ND) / (NA * ND) = Wn / Wp = NA / ND. W0 has a negative temperature coefficient. From the above two formulas, we get: {Wn = NA * √(2ε/ε) * Vφ / (NA * ND * (NA + ND))} {Wp = ND * √(2ε/ε) * Vφ / (NA * ND * (NA + ND))} The negative temperature coefficient is: {Q- = -qSWpNA} {Q+ = qSWnND = qSWpNA} The PN junction: Wn << Wp (ND >> NA) The P+ N junction: Wn >> Wp (ND << NA)
Page 53
PN Junction's I-V Characteristics:
# 1. Forward Characteristics: Positive (+) connected to Positive (+), Negative (-) connected to Negative (-).
- Due to the low resistance of the intrinsic region and the small resistance of the semiconductor, the external voltage is almost applied to the space charge region. The electric field direction is opposite to the contact electric field. The built-in electric field and the external electric field form a composite electric field E. The built-in electric field E decreases. The built-in voltage Vn, Vp, and Q all decrease. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp to Vp - Vn. The built-in voltage Vn decreases from Vn to Vn - Vp. The built-in voltage Vp decreases from Vp
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△ PN junction temperature characteristics: (I = I_s (e^(qT/kt) - 1))
$$V_T = \frac{kT}{q}$$
I_s: temperature increases → minority carrier concentration increases → I_s increases: for every 10°C increase in temperature, I_s increases.
∴ PN junction voltage remains constant, but as temperature increases, the forward current increases. The I-V characteristic shifts to the right. The I-V characteristic shifts downward (I_s increases).
△ PN junction reverse breakdown characteristics.
Reverse breakdown voltage V(br) is a limiting condition for PN junction reverse operation. In the breakdown region, the reverse current changes greatly, while the voltage changes little. This characteristic can be used to make a Zener diode.
1. Zener breakdown (<6V) (high impurity concentration, narrow space charge region).
Reverse bias voltage increases → valence electrons are ionized, covalent bonds are broken → space charge region produces a large number of electron-hole pairs → reverse current increases → field-induced breakdown.
Temperature increases → valence electrons more easily break covalent bonds; W0 decreases → Zener breakdown decreases.
2. Avalanche breakdown (>6V) (low impurity concentration, wide space charge region).
Reverse bias voltage increases → minority carrier energy increases → more frequent collisions with neutral atoms → valence electrons are knocked out → new electron-hole pairs are produced → collision electrons.
Temperature increases → lattice thermal vibration increases → carrier mobility decreases → V(br) increases.
The above two phenomena are reversible. Thermal breakdown will damage the PN junction, which is irreversible.
△ PN junction thermal response.
PN junction forward voltage → carrier mobility decreases → V(br) increases.
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The note discusses the capacitance effect in a PN junction diode. It covers two types of capacitance: the barrier capacitance and the diffusion capacitance.
1. **Barrier Capacitance**
- **Charge:** The barrier region has charge.
- **Voltage:** The voltage drop across the barrier region due to the electric field.
- **Reverse Voltage:** As the reverse voltage increases, the barrier electric field increases, leading to a higher potential difference and more charge. This is the charging process.
- **Reverse Voltage:** As the reverse voltage decreases, the barrier electric field decreases, leading to a lower potential difference and less charge. This is the discharging process.
- **Expressions:**
$$ V_{\phi} = \frac{kT}{q} \ln \frac{N_{A}N_{D}}{n_{i}^{2}} $$
$$ W_{0} = W_{n} + W_{p} = \sqrt{\frac{2\varepsilon}{q}} \cdot V_{\phi} \cdot \frac{N_{A} + N_{D}}{N_{A}N_{D}} $$
$$ Q = qS W_{p} N_{A} = qS W_{n} N_{D} $$
$$ C_{T} = \frac{dQ}{dV} $$
- **Small Current:**
$$ C_{T} = \frac{C_{T0}}{(1 - \frac{V}{V_{\phi}})^{n}} = \frac{\varepsilon S}{W_{0}} $$
- **Step Change:**
$$ n \approx \frac{1}{2} $$
- **Gradual Change:**
$$ n \approx \frac{1}{3} $$
- **Conclusion:**
$$ C_{T} \propto V $$
This relationship can be used to make a varactor diode.
2. **Diffusion Capacitance**
- **Charge:** The charge is the non-equilibrium carriers in the neutral regions.
- **Voltage:** The external voltage.
- **Forward Bias:** The carriers diffuse more (P holes → N, N electrons → P).
- **Result:** The neutral regions accumulate non-equilibrium carriers.
- **Expressions:**
$$ n_{p}(x) = [n_{p}(-W_{p}) - n_{p_{0}}] e^{\frac{x + W_{p}}{2W_{p}}} + n_{p_{0}} $$
$$ p_{n}(x) = [p_{n}(W_{n}) - p_{n_{0}}] e^{-\frac{x - W_{n}}{2W_{n}}} + p_{n_{0}} $$
- **Conclusion:**
$$ \Delta Q_{n} $$
$$ \Delta Q_{p} $$
The increase in forward voltage leads to an increase in the stored charge in the N and P regions, which is proportional to the change in voltage.
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The capacitance \(C_0\) mainly depends on the forward current through the PN junction. Therefore, \(C_0\) is proportional to the forward voltage. When operating in reverse, \(C_0\) is negligible. Generally, \(C_0 > C_T\). \(C_T\) and \(C_0\) are connected in parallel, so the total capacitance of the PN junction \(C_J = C_T + C_0\). When forward biased, \(C_0 \gg C_T\), so \(C_J \approx C_0\). When reverse biased, \(C_0 \rightarrow 0\), so \(C_J \propto C_T\).
4. Semiconductor Diode:
PN junction + casing + lead wires → semiconductor diode. (P-region positive, N-region negative).
Point contact type: low capacitance, rated current, reverse voltage small, high frequency, suitable for high-frequency circuits.
Planar contact type: large area, can withstand larger currents, high capacitance, low frequency, suitable for rectification.
Silicon surface: the same as current bipolar junction transistors and integrated circuits.
Voltage-current characteristic: \(i_b = I_s (e^{\frac{V_b}{nV_T}} - 1)\)
\(i_b = I_s (e^{\frac{V_b - I_b R_b}{nV_T}} - 1)\)
\(m\): emission coefficient \(\in (1, 2)\)
Main parameters:
Maximum forward average current (maximum rectifying current): \(I_F\)
Maximum reverse working voltage: \(V_R\)
Reverse current when not broken down: \(I_R\), the smaller, the better the unidirectional performance.
Maximum frequency: \(f_m\), above \(f_m\), junction capacitance cannot be ignored.
Static resistance: \(R_D = \frac{V_{DQ}}{I_{DQ}}\)
Dynamic resistance: \(r_d = \frac{dV_D}{dI_D} = \frac{V_T}{I_s e^{\frac{V_D}{nV_T}}} \approx \frac{V_T}{I_{DQ}} \approx \frac{26(mV)}{I_{DQ}(mA)}\)
Delta two-terminal model
1) Simplified model
$$i_b \rightarrow$$
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Here's the extracted text and formulas from the handwritten note, with placeholders for the diagrams:
---
2) $$I = \frac{V - V_{D}}{R}$$
3) $$I = \frac{V - V_{D}}{R}$$
2. Small Signal Model:
$$\begin{aligned}
&\text{Model only has small signal current. The condition is small signal.} \\
&\text{Where } r_s, r_d, C_j \text{ are related to the DC operating point.}
\end{aligned}$$
Delta Bipolar Transistor Applications:
1. Rectifier Circuit
2. Voltage Stabilization Circuit:
$$I_{Z_{\min}} < I_Z < I_{Z_{\max}}; V_0 = V_Z; r_z = \frac{\Delta V}{\Delta I}$$
3. Clamping Circuit:
$$\begin{aligned}
&\text{DC Analysis: } I_{DQ} \approx \frac{V_B - V_{BE}}{R + r_D} \\
&\text{AC Analysis: } f \text{ is low, not considering the effect of the base-emitter capacitor.} \\
&\text{The voltage across the diode is } V_d = (r_s + r_d) i_d \\
&\text{The current through the diode is } i_d = \frac{V_d}{R + r_s + r_d} \\
&\text{The voltage across the diode is } V_d = (r_s + r_d) i_d \\
&\text{The current through the diode is } i_d = I_{DQ} + i_d
\end{aligned}$$
4. Logic Gate Circuit:
$$\begin{aligned}
&Y = A \cdot B \\
&Y = A + B
\end{aligned}$$
---
The formulas and text are presented exactly as written in the original image. The diagrams are placeholders for
,
, etc., in the order they appear in the original document.
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5. Bipolar Junction Transistor
Two PN junctions form; electrons and holes participate in conduction; has amplification effect
1. Transistor Structure
NPN type
PNP type
Collector - N P N - Emitter
Base - Collector - P N P - Emitter
Base - Emitter
2. Transistor Working Principle (Example NPN)
Base region thin, doping concentration low
Emission region doping concentration much higher than B and C regions
VEB as forward bias on the emitter junction
VCC as reverse bias on the base region
PEO << NBO. PEO << PCO (PEO * NBO = N^2)
1) Forward bias on the emitter junction, electrons enter the base region, forming IEN. Holes enter the emitter region, forming IEP. Due to PEO << NBO, NBO >> PBO; IEN >> IEP.
IE = IEN + IEP.
2) Due to the low doping concentration in the base region, electrons (IEN) in the diffusion process recombine with holes in small quantities. Most reach the collector junction Jc boundary, pulled back by the collector's reverse electric field towards the collector region.
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3) Electron drift current Ic. And the minority carriers in the Collector region and the minority carriers in the Base region drift in the opposite direction in the Jc electric field, forming a reverse drift current (reverse saturation current) IcBo.
$$ I_B = I_{Bp} + I_{Ep} - I_{CBo} $$
$$ I_C = I_{cn} + I_{CBo} $$
$$ \therefore I_E = I_C + I_B $$
3) Transistor current distribution relationship
The current distribution within the transistor is determined by the voltage applied at the emitter and collector junctions, not by the connection mode (common base CB, common emitter CE, common collector CC).
1) CB
2) CE
3) CC
$$ \alpha = \frac{I_{Cn}}{I_E} $$
$$ = \frac{I_C - I_{CBo}}{I_E} $$
$$ = \frac{I_E - I_{Bp} - I_{Ep}}{I_E} $$
$$ I_C = \alpha (I_C + I_B) + I_{CBo} $$
$$ I_E = (\beta + 1) I_B + (\beta + 1) I_{CBo} $$
$$ \therefore I_C = \frac{\alpha}{1 - \alpha} I_B + \frac{1}{1 - \alpha} I_{CBo} $$
$$ \beta = \frac{\alpha}{1 - \alpha} $$
$$ \therefore I_C = \beta I_B + (\beta + 1) I_{CBo} = \beta I_B + I_{CBo} $$
If the base current I_{Bp} is much smaller than the collector current I_{Cn}, then I_{CBo} is negligible.
$$ I_{Ep} \ll I_{Cn} \leftarrow E region doping density $$
$$ I_{Bp} \ll I_{Cn} \leftarrow W_B is very small. $$
$$ I_{CBo} : I_B = 0 (base open circuit) $$
$$ \therefore I_C = \alpha I_E + I_{CBo} $$
$$ \therefore I_C = \alpha I_E. $$
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Four Modes of Transistor Operation
1. **Amplification State**: The base is forward-biased, and the collector is reverse-biased. The base current controls the collector current, which is almost independent of the collector voltage.
2. **Saturation State**: The base and collector are both forward-biased. The collector and base voltage drop is very small, almost like a closed switch.
3. **Cut-off State**: The base and collector are both reverse-biased. There is only a small leakage current, almost like an open switch.
4. **Reversed State**: The base is reverse-biased, and the collector is forward-biased. The collector and base voltage drop is different due to different doping concentrations in the two regions.
Ebers-Moll Theoretical Analysis
1. Ignore the resistance of the base and collector regions and the lead resistance. Assume the external voltage \( V_{EE} \) and \( V_{CC} \) are applied to the base and collector respectively.
2. Small current injection, not considering the recombination of carriers within the base region.
3. Do not consider the base width modulation effect, assuming the base width does not change with the base voltage.
4. Do not consider reverse breakdown.
Distribution of Minority Carriers in Emitter and Collector Regions
\[
P_{E}(x) - P_{E,0} = [P_{E}(-W_{E}) - P_{E,0}] \cdot e^{\frac{2x + W_{E}}{L_{B}}}
\]
\[
P_{C}(x) - P_{C,0} = [P_{C}(W_{C}) - P_{C,0}] \cdot e^{-\frac{x - W_{C}}{L_{C}}}
\]
Distribution of Minority Carriers in Base Region
\[
n_{B}(x) - n_{B,0} = \frac{n_{B}(0)}{sh \frac{W_{B}}{2L_{B}}} \left[ sh \frac{W_{B} - x}{2L_{B}} (e^{\frac{2x}{L_{B}}} - 1) - sh \frac{x}{2L_{B}} (e^{\frac{2x}{L_{B}}} - 1) \right]
\]
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Here's the extracted text and formulas from the handwritten note, with placeholders for the diagrams:
---
$I_{E} = I_{En} + I_{Ep}$
$I_{En} = qD_{n}S \frac{dN_{n}(\infty)}{dx}$
$I_{Ep} = -qD_{p}S \frac{dP_{p}(\infty)}{dx}$
$I_{C} = -I_{En} - I_{Ep}$
$I_{En} = qD_{n}S \frac{dN_{n}(x)}{dx}$
$I_{Ep} = -qD_{p}S \frac{dP_{p}(\infty)}{dx}$
Solve to get $I_{E} = I_{Es}(e^{\frac{V_{B}}{V_{T}}}-1) - \alpha_{R}I_{Cs}(e^{\frac{V_{B}}{V_{T}}}-1)$
$I_{C} = \alpha_{F}I_{Es}(e^{\frac{V_{B}}{V_{T}}}-1) - I_{Cs}(e^{\frac{V_{B}}{V_{T}}}-1)$
Where, $I_{Es}$ is the reverse saturation current of the emitter junction ($V_{Bc}=0$) when the emitter is reverse biased.
$I_{Cs}$ is the reverse saturation current of the collector junction ($V_{Bc}=0$) when the collector is reverse biased.
$\alpha_{F} = \frac{I_{C}}{I_{E}}|_{V_{Bc}=0}$ is the forward short circuit current gain.
$\alpha_{R} = \frac{I_{E}}{I_{C}}|_{V_{Bc}=0}$ is the reverse short circuit current gain.
Solve equations ① and ② to find $\alpha_{F}I_{Es} = \alpha_{R}I_{Cs} = I_{S}$, which is the saturation current of the transistor.
The effect of $V_{B}$ on $I_{Es}$, $I_{Cs}$, $\alpha_{F}$, $\alpha_{R}$ is influenced by the structure of the transistor.
1) Current Injection Form Equivalent Circuit
Let $I_{F} = I_{Es}(e^{\frac{V_{B}}{V_{T}}}-1)$
$I_{R} = I_{Cs}(e^{\frac{V_{B}}{V_{T}}}-1)$
Then $I_{E} = I_{F} - \alpha_{R}I_{R}$
$I_{C} = \alpha_{F}I_{F} - I_{R}$
2) Current Transmission Form Equivalent Circuit
From ① - $\alpha_{R} \times$ ② we get $I_{E} - \alpha_{R}I_{C} = (1 - \alpha_{R}\alpha_{F})I_{Es}(e^{\frac{V_{B}}{V_{T}}}-1)$
That is, $I_{E} = \alpha_{F}I_{C} + (1 - \alpha_{R}\alpha_{F})I_{Es}(e^{\frac{V_{B}}{V_{T}}}-1)$.
Note $I_{Es} = (1 - \alpha_{F}\alpha_{R})I_{Es}$ is the reverse saturation current of the base junction when the base is open circuit ($I_{C} = 0$) and the emitter is reverse biased.
---
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2) From (1) we get:
$$ I_C - \alpha_F I_E = (\alpha_F \alpha_F - 1) I_{cs} (e^{\frac{V_{BE}}{V_T}} - 1) $$
which is:
$$ I_C = \alpha_F I_E - (1 - \alpha_F \alpha_F) I_{cs} (e^{\frac{V_{BE}}{V_T}} - 1) $$
and $I_{co}$ is the reverse saturation current when the emitter is open circuit ($I_E = 0$).
3) Mixed hybrid equivalent circuit.
Rewrite (1) and (2):
$$ I_E = I_{Es} (e^{\frac{V_{BE}}{V_T}} - 1) - \alpha_R I_{cs} (e^{\frac{V_{CE}}{V_T}} - 1) = I_{Es} (e^{\frac{V_{BE}}{V_T}} - 1) - I_{s} (e^{\frac{V_{CE}}{V_T}} - 1) $$
$$ I_C = \alpha_F I_{Es} (e^{\frac{V_{BE}}{V_T}} - 1) - I_{cs} (e^{\frac{V_{CE}}{V_T}} - 1) = I_{s} (e^{\frac{V_{BE}}{V_T}} - 1) - I_{cs} (e^{\frac{V_{CE}}{V_T}} - 1) $$
Let $I_{cc} = I_{s} (e^{\frac{V_{BE}}{V_T}} - 1)$, $I_{EE} = I_{s} (e^{\frac{V_{CE}}{V_T}} - 1)$
$$ \beta_F = \frac{\alpha_F}{1 - \alpha_F} \quad \beta_R = \frac{\alpha_R}{1 - \alpha_R} $$
$$ I_{OT} = I_{cc} - I_{EE} $$
Then:
$$ I_E = \frac{I_{s}}{\alpha_F} (e^{\frac{V_{BE}}{V_T}} - 1) - I_{s} (e^{\frac{V_{CE}}{V_T}} - 1) = \frac{I_{cc}}{\alpha_F} - I_{EE} = \frac{I_{cc}}{\alpha_F} - I_{cc} + I_{cc} - I_{EE} = \frac{I_{cc}}{\beta_F} + I_{cc} $$
$$ I_C = I_{s} (e^{\frac{V_{BE}}{V_T}} - 1) - \frac{I_{cs}}{\alpha_R} (e^{\frac{V_{CE}}{V_T}} - 1) = I_{cc} - \frac{I_{EE}}{\alpha_R} = I_{cc} - I_{EE} + I_{EE} - \frac{I_{EE}}{\alpha_R} = -\frac{I_{EE}}{\beta_R} + I_{cc} $$
The equivalent circuit includes three elements and three parameters $I_{s}$, $\beta_F$, $\beta_R$, which is the most common model.
4) According to Ebers-Moll's model, re-analyze the four working modes of the transistor.
1) Amplification state (forward bias: $V_{BE} > 0$; reverse bias: $V_{BC} < 0$).
$$ \therefore |V_{BC}| >> V_T \quad (\text{I}_{cs} \to 0, e^{\frac{V_{BC}}{V_T}} - 1 \to -1) $$
$$ I_C \approx \alpha_F I_E + (1 - \alpha_F \alpha_F) I_{cs} \approx \alpha_F I_E $$
$$ I_B = I_E - I_C \approx (1 - \alpha_F) I_{Es} (e^{\frac{V_{BE}}{V_T}} - 1) $$
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The note discusses the behavior of a transistor in different operating states. It starts by explaining the relationship between collector current (Ic), base current (Ib), and emitter current (Ie) under normal operating conditions. It notes that as the base-emitter voltage (VBE) increases, Ie, Ib, and Ic all increase. However, when VBE reaches a certain value, Ie, Ib, and Ic follow an exponential pattern of change.
2) Cut-off State (JE reverse biased: VBE < 0; JC reverse biased: VBC < 0):
- Since |VBC| >> Vt and |VBE| >> Vt,
- IE ≈ -Ies + αF Ics
- IC ≈ -αF Ies + Ics
- IB = Ie - IC ≈ -(1 - αF) Ies - (1 - αF) Ics.
- It is evident that all currents are very small, indicating the transistor exhibits high resistance characteristics.
3) Saturation State (JE forward biased: VBE > 0; JC forward biased: VBC > 0):
- From (1) and (2), it is known that VBC makes IB and IC smaller, while VBE makes IE and IC larger.
- Therefore, under the same VBE, the saturation state's collector and base currents are smaller than in the amplification state.
- Since both JE and JC are in the forward biased state, they are in a low resistance state, and CE is nearly short-circuited.
4) Reverse State (JE reverse biased: VBE < 0; JC forward biased: VBC > 0):
- IE ≈ αF IC - (1 - αF) Ies = αF IC - Ies.
- Due to αF being very small, IC's control over IE is weak.
The note also mentions the transient model of a transistor and its non-linear characteristics.
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5. Transistor Characteristics Curves
Example: CE
1) Input Characteristics Curve
$$i_B = f(V_{BE}) \mid V_{CE} = const$$
$$\therefore I_B = I_{Bp} + I_{Ep} - I_{CE}$$
$$\because \text{When } V_{CE} \text{ is constant, } I_{Ep} \text{ decreases (electrons-recombination decreases)}$$
$$\therefore I_B \text{ decreases}$$
$$\because V_{CE} = 0 \text{ corresponds to the lowest point on the curve}$$
$$\text{When } V_{CE} > 1V \text{, } I_B \text{ decreases as } V_{CE} \text{ increases, the characteristic curve shifts to the right.}$$
$$\text{Because } V_{CE} \uparrow, W_B \downarrow \text{ so } I_B \downarrow. (\text{Base region becomes narrower, base resistance decreases, and the base current increases.})$$
$$\text{This is the base width modulation effect.}$$
$$\text{When } V_{BE} < 0 \text{, the base current is very small. When } |V_{CE}| \text{ increases to a certain extent, the base region becomes very narrow, and the base current increases.}$$
2) Output Characteristics Curve
$$i_C = f(V_{CE}) \mid V_{BE} = const$$
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$$I_{C} = I_{E} - I_{B} + I_{B0}$$
$$\because V_{CE} \uparrow, \text{Collector space charge region widens, } W_{B} \downarrow$$
$$\therefore I_{B} \downarrow$$
$$\therefore I_{C} \uparrow$$
$$\text{When the base region is small, the base width } W_{B} \text{ has a greater impact on } I_{C}$$
$$\text{The same } V_{CE} \text{ under } I_{C}-V_{CE} \text{ curve in the active region has a greater slope}$$
$$\therefore V_{A} \text{ is smaller}$$
$$\text{In the active state, } I_{C} \approx \alpha_{F} I_{E} \left(e^{\frac{V_{CE}}{V_{A}}} - 1\right) + \left(1 - \alpha_{F} \alpha_{R}\right) I_{C} \text{ should be modified to}$$
$$I_{C} \approx \alpha_{F} I_{E} \left(e^{\frac{V_{CE}}{V_{A}}} - 1\right) \left(1 + \frac{V_{CE}}{V_{A}}\right) = I_{C} \left(e^{\frac{V_{CE}}{V_{A}}} - 1\right) \left(1 + \frac{V_{CE}}{V_{A}}\right)$$
$$\therefore \text{In the active region, the transistor output resistance}$$
$$r_{ce} = \frac{V_{A} + V_{CE}}{I_{C}}$$
$$\text{In the cutoff region, when } V_{BE} = 0 \text{, } I_{C} = I_{C0} \approx 0 \text{ (Collector reverse saturation current)}$$
$$\text{In the saturation region, } V_{CE} \text{ is very small, } W_{B} \text{ is very wide, Collector collection ability is weak,}$$
$$\therefore I_{C} \text{ increases with the increase of } V_{CE}$$
$$\text{In the breakdown region, } V_{BE} \text{ increases to a certain extent, } J_{B} \text{ breaks down, } I_{C} \text{ increases rapidly}$$
$$\because \text{Base region and collector region doping concentration is low}$$
$$\therefore \text{Breakdown occurs, breakdown voltage decreases with the increase of } V_{BE}$$
$$(\text{Because } V_{BE} \uparrow, I_{C} \uparrow, \text{through } J_{B} \text{ the current density increases, the probability of collision increases,}$$
$$\text{the breakdown voltage required for breakdown decreases})$$
$$\therefore \text{When } V_{BE} = 0 \text{, the breakdown voltage increases.}$$
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3) Output Characteristics Curve $i_{C} = f(U_{CE})|_{i_{B} = const}$
- The output resistance $r_{o}$ when $i_{B}$ is constant is less than the output resistance $r_{o}$ when $U_{CE}$ is constant.
- $i_{C} = \beta i_{B} + (\beta + 1) I_{CBO}$.
- When $i_{E} = 0$, $i_{C} = I_{CBO} = -i_{B}$. This is the cutoff region. In engineering, it is often approximated as $i_{B} = 0$.
- Below this region is the cutoff region. At this point, $I_{CBO}(\beta + \beta) = I_{C}$ (穿透电流).
- Saturation region, $i_{C}$ remains constant. As $U_{CE}$ decreases, $i_{C}$ decreases rapidly. At this point, $i_{C} < \beta i_{B}$.
- The reverse breakdown voltage $U_{BECBO}$ is the voltage at which the base is open and the collector and emitter are reverse biased.
6) Temperature Impact on Transistor Characteristics
For a PN junction, $I = I_{s}(e^{qU_{B}/kT} - 1)$. As temperature increases, $V_{T}$ increases ($V_{T} = \frac{kT}{q}$) and $I_{s}$ also increases. $I_{s} \approx 2.2^{T/10}$.
- The input characteristic curve shifts left as temperature increases.
- Experimentally, if $I_{B}$ remains constant, for every 1°C increase in temperature, $U_{BE}$ decreases by 2-2.5 mV. Thus, $\frac{\Delta U_{BE}}{\Delta T}|_{I_{B} = const} = -(2-2.5) mV$.
Due to:
1. When temperature increases, the reverse current $I_{CBO}$ increases.
2. When temperature increases, the current amplification factor $\beta$ increases. The base region carrier recombination decreases. Thus, $\alpha = \alpha_{F} = \frac{I_{C}}{I_{B}}$ increases. Therefore, $\beta = \frac{1}{1-\alpha}$ increases.
- In engineering, $\frac{1}{\beta} \frac{dB}{dT} = (0.5\% - 1\%)/^{\circ}C$.
- Overall, as temperature increases, $I_{CBO}$, $\beta$ increase, and $i_{C} - U_{CE}$ input increases. Thus, $I_{B} = I_{CBO} + I_{B} - I_{CBO}$.
In summary, as temperature increases, $I_{CBO}$ and $\beta$ increase, and $i_{C} - U_{CE}$ input increases.
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7. Bipolar Transistor Main Parameters
1. DC Parameters
△ Common Emitter DC Current Gain β:
When VCE is constant, β = $$\frac{Ic - IcEo}{Ie} \approx \frac{Ic}{Ie}$$
△ Common Base DC Current Gain α:
When VCB is constant, α = $$\frac{Ic - IcBo}{Ie} \approx \frac{Ic}{Ie}$$
△ Emitter Open Circuit Collector Reverse Saturation Current IcBo
Test Circuit:
△ Collector Open Circuit Emitter Reverse Saturation Current IeBo
Test Circuit:
△ Base Open Circuit Collector and Emitter Current IcEo
Test Circuit:
[DIAGRAM 3]
IcEo = ($\overline{\beta}$ + 1) IcBo. This forms a parasitic amplification effect, much greater than IcBo, IeBo.
Page 68
2) AC Parameters:
- Common Emitter AC Current Gain β = ΔIC / ΔIB | VCE = const.
- Common Base AC Current Gain α = ΔIC / ΔIE | VBE = const.
- Characteristic Frequency fT. Due to the existence of junction capacitors, the phase shift between IC and IB increases. When fT is sufficiently high, the phase shift between IC and IB is π/2. β = 2c / Ib. The frequency at which β drops to 1 is the characteristic frequency fT.
3) Limit Parameters:
- Collector Maximum Allowable Current Icm. When IC is too small, the recombination of carriers in the base region reduces the base current, thus decreasing IC. When IC is too large, the injection of carriers into the base region is too high, and the base region becomes highly doped. To maintain the neutrality of the base region, the external circuit must inject a large number of holes into the base region, which will diffuse into the emitter region, causing IC to decrease. When IC drops to 2/3 of its maximum value, the corresponding collector current is Icm.
- Emitter Open Circuit Collector Reverse Breakdown Voltage V(BR)CEO.
$$
\beta = \frac{\Delta I_C}{\Delta I_B} \mid V_{CE} = \text{const.}
$$
$$
\alpha = \frac{\Delta I_C}{\Delta I_E} \mid V_{BE} = \text{const.}
$$
$$
\beta = \frac{2c}{I_b}
$$
$$
V_{(BR)CEO}
$$
Page 69
△ Base open circuit when the collector and emitter have a reverse breakdown voltage V(BR)CEO
$$V(BR)CEO > V(BR)CEO > V(BR)BBO$$
△ Collector maximum allowable power dissipation Pcm.
$$Pc \propto Ic \cdot Ic$$
In the amplification state, Vce is mostly dropped on the collector. The collector mainly dissipates power.
$$\therefore CE mode, ensure Ic < Icm, Vce < V(BR)CEO, Pc < Pcm$$
△ Transistor application.
When working in the amplification region, it has a positive control effect, equivalent to a controlled current source.
When working in the saturation region and cutoff region, it has a switching characteristic, equivalent to a controlled switch.
1) Transistor amplification circuit.
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The note discusses the static operating point of a transistor and the behavior of a transistor switch circuit. It explains how to calculate the base-emitter voltage (Vbe), the base-collector voltage (Vbc), and the collector current (ic) in a common-emitter configuration. The formulas include:
- Total input voltage: V1 = Vbb + Vb
- Base-emitter voltage: Vbe = Vbeq + Vbe
- Base-collector voltage: Vbc = Vbcq + Vbc
- Collector current: ic = Ic + ic = Ic + Icm sin(ωt)
- Output voltage: Vo = Vcc - Rc ic = Vcc - Rc Ic - Rc Icm sin(ωt) = Vceq + Vcm sin(ωt + 180°)
- Where Vceq = Vcc - Rc Ic and Vcm = Rc Icm
The note also discusses the transistor switch circuit, where the transistor is either cut-off or saturated. It provides formulas for the collector current in both states:
- Cut-off: ic ≈ 0, ic ≈ 0
- Saturation: ic = (Vcc - Vce(sat)) / Rc ≈ Vcc / Rc
- If ignoring saturation voltage, Vce(sat), Vo ≈ 0
The note concludes with a summary of the transistor's operating state judgment method:
- Cut-off: V1 < Vth
- Saturation/Amplification: When the transistor is in saturation, Vcb = 0, Vce = Vbe
- In the saturation region, ic ≈ β ib, assuming ib = ibs, then ic = ibs = (Vcc - Vbe) / Rc.
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No.
Date
When \( i_B > I_{BS} \), it works in the saturation region (as shown in the figure), \( i_C = \frac{V_{CC} - V_{CE(sat)}}{R_C} \).
When \( 0 < i_B < I_{BS} \), it works in the amplification region (as shown in the figure), \( i_C = \beta i_B \).
\[
i_C \quad \text{vs} \quad V_{CE}
\]
\[
V_{CE} = 0 \quad i_C \text{max}
\]
\[
i_C \text{min}
\]
Bipolar Junction Transistor Quantitative Solution
\[
\begin{array}{ccc}
\text{Emitter} & \text{Base} & \text{Collector} \\
N^+ & N & P \\
\end{array}
\]
\[
\begin{array}{ccc}
x_1 & + & x_2 \\
\end{array}
\]
\[
\begin{array}{ccc}
+ & W & x_3 \\
\end{array}
\]
The Definitions ...
\[
N_E = N_{BE}, \quad N_B = N_{AB}, \quad N_C = N_{PC}
\]
\[
D_E = D_P, \quad D_B = -D_N, \quad D_C = D_P
\]
\[
L_E = L_P, \quad L_B = L_N, \quad L_C = L_P, \quad \tau_E = \tau_P, \quad \tau_B = \tau_N, \quad \tau_C = \tau_P
\]
\[
p_{B0} = p_{N0} = n^2 / N_E, \quad n_{B0} = n_{P0} = p^2 / N_B, \quad p_{C0} = p_{N0} = n^2 / N_C
\]
Emitter Region:
\[
\begin{aligned}
0 &= D_E \left. \frac{d^2 \Delta p_E}{dx_1^2} - \frac{\Delta p_E}{\tau_P} \right|_{\Delta p_E(x_1 \to \infty) = 0, \Delta p_E(x_1 = 0) = p_{E0} (e^{\frac{V_{BE}}{T}} - 1)} \\
\end{aligned}
\]
Base Region:
\[
\begin{aligned}
0 &= D_B \left. \frac{d^2 \Delta n_B}{dx_2^2} - \frac{\Delta n_B}{\tau_B} \right|_{\Delta n_B(0) = n_{B0} (e^{\frac{V_{BE}}{T}} - 1), \Delta n_B(W) = n_{B0} (e^{\frac{V_{BC}}{T}} - 1)} \\
\end{aligned}
\]
Collector Region:
\[
\begin{aligned}
0 &= D_C \left. \frac{d^2 \Delta p_C}{dx_3^2} - \frac{\Delta p_C}{\tau_C} \right|_{\Delta p_C(x_3 \to \infty) = 0, \Delta p_C(x_3 = 0) = p_{C0} (e^{\frac{V_{BC}}{T}} - 1)} \\
\end{aligned}
\]
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The problem solution in the emitter and collector quasi-neutral region:
$$\Delta P_{E}(x_{1}) = P_{E0}(e^{\frac{V_{BE}}{V_{T}}}-1)e^{-\frac{2x_{1}}{L_{E}}} \quad \therefore I_{Ep} = -qS\frac{D_{E}}{L_{E}}\left.\frac{d\Delta P_{E}}{dx_{1}}\right|_{x_{1}=0}$$
$$= qS\frac{D_{E}}{L_{E}}P_{E0}(e^{\frac{V_{BE}}{V_{T}}}-1)$$
$$\Delta P_{C}(x_{3}) = P_{C0}(e^{\frac{V_{BC}}{V_{T}}}-1)e^{-\frac{2x_{3}}{L_{C}}} \quad \therefore I_{Cp} = qS\frac{D_{C}}{L_{C}}\left.\frac{d\Delta P_{C}}{dx_{3}}\right|_{x_{3}=0}$$
$$= -qS\frac{D_{C}}{L_{C}}P_{C0}(e^{\frac{V_{BC}}{V_{T}}}-1).$$
The problem solution in the base quasi-neutral region:
$$\Delta n_{B}(x) = A_{1}e^{-\frac{x}{L_{B}}} + A_{2}e^{\frac{x}{L_{B}}}$$
$$\therefore \Delta n_{B}(0) = n_{B0}(e^{\frac{V_{BC}}{V_{T}}}-1) = A_{1} + A_{2}$$
$$\text{and} \quad \Delta n_{B}(W) = n_{B0}(e^{\frac{V_{BC}}{V_{T}}}-1) = A_{1}e^{-\frac{W}{L_{B}}} + A_{2}e^{\frac{W}{L_{B}}}$$
$$\therefore \Delta n_{B}(x) = \Delta n_{B}(0)\frac{sh\left(\frac{(W-x)}{L_{B}}\right)}{sh\left(\frac{W}{L_{B}}\right)} + \Delta n_{B}(W)\frac{sh\left(\frac{x}{L_{B}}\right)}{sh\left(\frac{W}{L_{B}}\right)}$$
$$\therefore I_{En} = -qS\frac{D_{B}}{L_{B}}\left.\frac{d\Delta n_{B}}{dx_{2}}\right|_{x_{2}=0} = qS\frac{D_{B}}{L_{B}}n_{B0}\left[\frac{sh\left(\frac{W}{L_{B}}\right)}{sh\left(\frac{W}{L_{B}}\right)}(e^{\frac{V_{BC}}{V_{T}}}-1) - \frac{1}{sh\left(\frac{W}{L_{B}}\right)}(e^{\frac{V_{BC}}{V_{T}}}-1)\right]$$
$$I_{Cn} = -qS\frac{D_{B}}{L_{B}}\left.\frac{d\Delta n_{B}}{dx_{2}}\right|_{x_{2}=W} = qS\frac{D_{B}}{L_{B}}n_{B0}\left[\frac{1}{sh\left(\frac{W}{L_{B}}\right)}(e^{\frac{V_{BC}}{V_{T}}}-1) - \frac{ch\left(\frac{W}{L_{B}}\right)}{sh\left(\frac{W}{L_{B}}\right)}(e^{\frac{V_{BC}}{V_{T}}}-1)\right]$$
$$\therefore I_{E} = I_{Ep} + I_{En} = qS\left[\left(\frac{D_{E}}{L_{E}}P_{E0} + \frac{D_{B}}{L_{B}}n_{B0}\frac{ch\left(\frac{W}{L_{B}}\right)}{sh\left(\frac{W}{L_{B}}\right)}\right)(e^{\frac{V_{BE}}{V_{T}}}-1) - \left(\frac{D_{B}}{L_{B}}n_{B0}\frac{1}{sh\left(\frac{W}{L_{B}}\right)}\right)(e^{\frac{V_{BC}}{V_{T}}}-1)\right]$$
$$I_{C} = I_{Cp} + I_{Cn} = qS\left[\left(\frac{D_{B}}{L_{B}}n_{B0}\frac{1}{sh\left(\frac{W}{L_{B}}\right)}\right)(e^{\frac{V_{BC}}{V_{T}}}-1) - \left(\frac{D_{C}}{L_{C}}P_{C0} + \frac{D_{B}}{L_{B}}n_{B0}\frac{ch\left(\frac{W}{L_{B}}\right)}{sh\left(\frac{W}{L_{B}}\right)}\right)(e^{\frac{V_{BC}}{V_{T}}}-1)\right]$$
$$\therefore \alpha_{dc} = \frac{1}{ch\left(\frac{W}{L_{B}}\right) + \left(\frac{D_{E}}{D_{B}}\frac{L_{B}}{L_{E}}\frac{N_{B}}{N_{E}}\right)sh\left(\frac{W}{L_{B}}\right)}$$
$$\beta_{dc} = \frac{1}{1 - \alpha_{dc}} = \frac{1}{ch\left(\frac{W}{L_{B}}\right) + \left(\frac{D_{E}}{D_{B}}\frac{L_{B}}{L_{E}}\frac{N_{B}}{N_{E}}\right)sh\left(\frac{W}{L_{B}}\right)}$$
When the base width is much less than the minority carrier diffusion length.
Page 73
ΔnB(x) ≈ ΔnB(0) + [ΔnB(W) - ΔnB(0)]x/W
αdc ≈ 1 + DB/NB * W/LB + 1/2(W/LB)^2 ≈ 1 + DB * WN/B (LB >> W)
Pdc ≈ DB * NE * W/LB + 1/2(W/LB)^2 ≈ DB * L * NE / (DB * W * NB) most of the minority carriers make it across the base.
Mode | Emitter-Base | Collector-Base | VBE | IB | VCE (VCE = VBE + VCB) | IC | IE
-----|-------------|--------------|-----|----|-----------------------|-----|-----
Active | Forward | Reverse | ~0.6V | >0 | >VBE | IB * β | IE / α
Saturated | Forward | Forward | >0.7 | >IC/β |
△共射极输入特性: (VCE = const)
IB = IC - IC = qS * DE/LE * PEO (e^(VBE/VT) - 1) + qS * DC/LE * PEO (e^(VBE/VT) - 1)
= qS [DE/LE * PEO (e^(VBE/VT) - 1) + DC/LE * PEO (e^(VBE/VT) - 1)]
△共射极输出特性: (VBE = const)
IC = qS [(DB/LE * nBO * sh(W/LB)) (e^(VBE/VT) - 1) - (DB/LE * PEO + DB/LE * nBO * sh(W/LB)) (e^(VBE/VT) - 1)]
≈ qS [DB/LE * nBO * sh(W/LB) (e^(VBE/VT) - 1) (1 + VCE/VT)]
△共射极输出特性: (VBE = const)
综合上两式 (消去 VBE)
e^(VBE) = [qS * DE/LE * PEO + qS * DC/LE * PEO / e^(VBE)]^(-1) (IB + qS * DE/LE * PEO + qS * DC/LE * PEO)
= qS (DB/LE * PEO + DB/LE * nBO * sh(W/LB)) (e^(VBE) - 1) (IB + qS * DE/LE * PEO + qS * DC/LE * PEO / e^(VBE))
= qS (DB/LE * PEO + DB/LE * nBO * sh(W/LB)) (e^(VBE) - 1) (IB + qS * DE/LE * PEO + qS * DC/LE * PEO / e^(VBE))
= qS (DB/LE * PEO + DB/LE * nBO * sh(W/LB)) (e^(VBE) - 1) (IB + qS * DE/LE * PEO + qS * DC/LE * PEO / e^(VBE))
= qS (DB/LE * PEO + DB/LE * nBO * sh(W/LB)) (e^(VBE) - 1) (IB + qS * DE/LE * PEO + qS * DC/LE * PEO / e^(VBE))
= qS (DB/LE * PEO + DB/LE * nBO * sh(W/LB)) (e^(VBE) - 1) (IB + qS * DE/LE * PEO + qS * DC/LE * PEO / e^(VBE))
= qS (DB/LE * PEO + DB/LE * nBO * sh(W/LB)) (e^(VBE) - 1) (IB + qS * DE/LE * PEO + qS * DC/LE * PEO / e^(VBE))
= qS (DB/LE * PEO + DB/LE * nBO * sh(W/LB)) (e^(VBE) - 1) (IB + qS * DE/LE * PEO + qS * DC/LE * PEO / e^(VBE))
= qS (DB/LE * PEO + DB/LE * nBO * sh(W/LB)) (e^(VBE) - 1) (IB + qS * DE/LE * PEO + qS * DC/LE * PEO / e^(VBE))
= qS (DB/LE * PEO + DB/LE * nBO * sh(W/LB)) (e^(VBE) - 1) (IB + qS * DE/LE * PEO + qS * DC/LE * PEO / e^(VBE))
= qS (DB/LE * PEO + DB/LE * nBO * sh(W/LB)) (e^(VBE) - 1) (IB + qS * DE/LE * PEO + qS * DC/LE * PEO / e^(VBE))
= qS (DB/LE * PEO + DB/LE * nBO * sh(W/LB)) (e^(VBE) - 1) (IB + qS * DE/LE * PEO + qS * DC/LE * PEO / e^(VBE))
= qS (DB/LE * PEO + DB/LE * nBO * sh(W/LB)) (e^(VBE) - 1) (IB + qS * DE/LE * PEO + qS * DC/LE * PEO / e^(VBE))
= qS (DB/LE * PEO + DB/LE * nBO * sh(W/LB)) (e^(VBE) - 1) (IB + qS * DE/LE * PEO + qS * DC/LE * PEO / e^(VBE))
= qS (DB/LE * PEO + DB/LE * nBO * sh(W/LB)) (e^(VBE) - 1) (IB + qS * DE/LE * PEO + qS * DC/LE * PEO / e^(VBE))
= qS (DB/LE * PEO + DB/LE * nBO * sh(W/LB)) (e^(VBE) - 1) (IB + qS * DE/LE * PEO + qS * DC/LE * PEO / e^(V
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6. Field Effect Transistor.
\{IGFET\}
N-channel Enhancement
N-channel Depletion
P-channel Enhancement
P-channel Depletion
\{JFET\}
N-channel
P-channel
MOSFET (Metal Oxide Semiconductor Field Effect Transistor) ∈ IGFET
(Voltage applied to the gate)
G - Gate
D - Drain
S - Source
Vgs = 0 when D and S regions are in the depletion layer (space charge layer) without a conductive channel.
Vgs > 0 when in the SiO2 insulating layer, a uniform electric field is generated from the gate to the substrate, attracting electrons in the P-type substrate to the substrate surface, combining with holes, forming a very thin depletion layer.
Vgs > Vgs(th) when the surface layer of free electrons is greater than the surface layer of holes, the surface layer of P-type turns into N-type, becoming a reverse layer, connecting D and S two N+ regions. At this time, if Vds > 0 (forward voltage), then a drain-to-source current is generated, the transistor is turned on.
When Vgs > Vgs(th), a conductive channel forms. At this time, if Vgs = 0 (Vgs = Vgs), the electric field in the SiO2 insulating layer is uniform, the conductive channel is rectangular.
When Vds > 0, a drain current Id is generated, and the electric field from S to D gradually increases. At this time, the electric field is no longer uniform, the conductive channel thickness from S to D gradually decreases.
Page 75
The drain-source voltage \(V_{DS}\) equals the gate-source voltage \(V_{GS}\) minus the threshold voltage \(V_{GS(\alpha)}\). When \(V_{DS} = V_{GS(\alpha)}\), the channel at the drain end just disappears, forming a pinch-off.
When \(V_{DS} > V_{GS} - V_{GS(\alpha)}\), i.e., \(V_{DS} < V_{GS(\alpha)}\), the pinch-off point extends towards the source, forming a pinched-off region (the depletion layer). The voltage between the pinch-off point and the source is \(V_{GS(\alpha)}\), and the voltage between the pinch-off point and the gate is \(V_{GS} - V_{GS(\alpha)}\). The rest of the \(V_{DS} - (V_{GS} - V_{GS(\alpha)})\) voltage drops on the pinched-off region, forming a strong electric field, which maintains the pinch-off after formation. The pinch-off point shifts to the left as \(V_{GS}\) increases, but the voltage between the pinch-off point and the source \(V_{GS} - V_{GS(\alpha)}\) remains constant. The channel length changes little, and the channel resistance changes little.
This means that after \(V_{DS} > V_{GS} - V_{GS(\alpha)}\), \(V_{GS}\) remains constant, and \(I_{D}\) increases with the increase of \(V_{DS}\). Near the pinch-off point, \(I_{D}\) is only related to \(V_{GS}\). The thicker the depletion layer, the smaller the channel resistance, and the larger the \(I_{D}\).
The output characteristic curve shows the relationship between \(I_{D}\) and \(V_{DS}\) in the variable resistance region. When \(V_{GS} > V_{GS(\alpha)}\), the pinch-off point extends towards the source, forming a pinched-off region. The voltage between the pinch-off point and the source is \(V_{GS(\alpha)}\), and the voltage between the pinch-off point and the gate is \(V_{GS} - V_{GS(\alpha)}\).
In the variable resistance region, \(I_{D} = \frac{k_{p}}{2} \frac{W}{L} \left[ 2 \left( V_{GS} - V_{GS(\alpha)} \right) V_{DS} - V_{DS}^{2} \right]\), where \(k_{p} = \mu_{n} C_{ox}\). \(\mu_{n}\) is the electron mobility in the channel, and \(C_{ox}\) is the oxide layer capacitance per unit area. \(W\) is the channel width, and \(L\) is the channel length.
Page 76
In the saturation region (constant current region), ib ~ ibsat = $$\frac{K}{2} \frac{W}{L} [2(V_{as} - V_{as(s)})V_{bs} - V_{bs}^2]$$
≈ $$\frac{K}{2} \frac{W}{L} [2(V_{as} - V_{as(s)})^2 - (V_{as} - V_{as(s)})^2]$$
≈ $$\frac{K}{2} \frac{W}{L} \cdot (V_{as} - V_{as(s)})^2$$ (breakdown point)
To improve accuracy, considering the channel length modulation effect: Vbs increases, breakdown point → S, L decreases, channel resistance decreases. The breakdown point and source voltage remain as Vbs - Vbs(s), so ib - Vbs curve in the saturation region shows a slope. Extending Vbs corresponding to each inclined line, it reaches VA (30~50V). Early voltage L越short, Vbs越small.
Considering channel length modulation, ib = $$\frac{K}{2} \frac{W}{L} \cdot (V_{as} - V_{as(s)})^2 (1 + \frac{V_{bs}}{V_A})$$
∴ rds = $$\frac{V_A + V_{bs(s)}}{I_{ds}}$$
In the breakdown region, Vbs increases to a certain value, breakdown. Breakdown voltage increases with Vbs. Because Vbs increases, the same Vbs breakdown field strength decreases. Additionally, the breakdown between the source and drain of the PN junction occurs, D and S between the breakdown, C and S between the breakdown. When the Vbs is high enough, the SiO2 breakdown occurs.
2. Transfer characteristic curve. ib
ib = $$\frac{K}{2} \frac{W}{L} (V_{as} - V_{as(s)})^2 (1 + \frac{V_{bs}}{V_A})$$, Vbs increases, the characteristic curve shifts left. This is the result of channel length modulation effect.
Transconductance g_m = $$\frac{dib}{dV_{as}} |_{V_{bs} = const} = \frac{K}{L} \frac{W}{L} (V_{as} - V_{as(s)}) (1 + \frac{V_{bs}}{V_A})$$
= $$\frac{2Kp}{L} (V_{as} - V_{as(s)}) (1 + \frac{V_{bs}}{V_A})$$
= $$\sqrt{2Kp \frac{W}{L} (1 + \frac{V_{bs}}{V_A})} ib$$ (neglecting channel length modulation effect).
Page 77
3. Threshold Voltage Effect
To ensure that the N-MOS FET's D and B junctions are in the cutoff state, B (P region) is connected to the lowest voltage in the circuit. The back gate and source have a negative voltage \( V_{BS} \).
G and B are equivalent to a capacitor. When \( V_{BS} \) is constant, the thicker the depletion region in B, the more negative charges there are in the space charge region. This reduces the number of electrons in the channel, increasing the channel resistance and decreasing the current. Therefore, when the back gate is biased negatively, \( V_{BS} > V_{BS(off)} \).
The back gate is connected to the lowest voltage in the circuit. The back gate and source have a negative voltage \( V_{BS} \).
1. Cutoff region: \( V_{BS} < V_{BS(off)} \), \( I_D = 0 \).
2. Variable resistance region: \( V_{BS} > V_{BS(off)} \), \( 0 < V_{BS} < V_{BS} - V_{BS(off)} \).
\[ I_D = \frac{K}{2} \frac{W}{L} \left[ 2 \left( V_{BS} - V_{BS(off)} \right) V_{BS} - V_{BS}^2 \right] \]
3. Saturation region: \( V_{BS} > V_{BS(off)} \), \( V_{BS} \geq V_{BS} - V_{BS(off)} \).
\[ I_D \approx \frac{K}{2} \frac{W}{L} \left[ V_{BS} - V_{BS(off)} \right]^2 \]
[DIAGRAM 2]
The saturation current \( I_{DSS} \) is given by:
\[ I_{DSS} = \frac{K}{2} \frac{W}{L} \left[ 2 \left( V_{BS} - V_{BS(off)} \right) \left( 1 + \lambda V_{BS} \right) \right] \]
\[ I_D \approx I_{DSS} \left( 1 - \frac{V_{BS}}{V_{BS(off)}} \right)^2 \]
Considering the channel length modulation effect, \( I_D = \frac{K}{2} \frac{W}{L} \left( V_{BS} - V_{BS(off)} \right)^2 \left( 1 + \lambda V_{BS} \right) \approx I_{DSS} \left( 1 - \frac{V_{BS}}{V_{BS(off)}} \right)^2 \left( 1 + \lambda V_{BS} \right) \).
Page 78
MOSFET's Transient Model
# Capacitors:
- Linear Capacitors (Planar Capacitors): \(C_{SS'}, C_{SS}, C_{DD}\) (C: Channel)
- Nonlinear Capacitors (Affected by Bias Voltage): \(C_{BS}, C_{BD}, C_{BC}\) (PN Junction Capacitors)
- Among them, \(\frac{1}{C_{BC}} + \frac{1}{C_{BC}} = \frac{1}{C_{BS}}\)
# Linear: \(i_D = \frac{k}{2} \frac{W}{L} [2(V_{GS} - V_{GS(off)})V_{DS} - V_{DS}^2]\) or \(\frac{k}{2} \frac{W}{L} [2(V_{GS} - V_{GS(off)})V_{DS} - V_{DS}^2]\)
# Saturation: \(i_D = \frac{k}{2} \frac{W}{L} (V_{GS} - V_{GS(off)})^2 (1 + \frac{V_{DS}}{V_A})\) or \(\frac{k}{2} \frac{W}{L} (V_{GS} - V_{GS(off)})^2 (1 + \frac{V_{DS}}{V_A})\)
Source (S) and Drain (D) Can Be Interchanged
# NMOS and PMOS:
- \(k_n = \mu_n C_{ox} \propto 4 \times \mu_p C_{ox} = PMOS's k_p\)
# Due to MOSFETs, the carriers involved are only electrons. The temperature has little effect on their concentration. Therefore, MOSFETs have good temperature stability. Temperature affects two aspects: \(T \uparrow\), \(W\) (channel width) \(\downarrow\), current density \(\downarrow\); \(T \uparrow\), \(\mu\) (\(\mu_n\)) \(\downarrow\), \(i_0\) \(\downarrow\).
Junction Field-Effect Transistor - JFET
# Transfer Characteristics:
- \(V_{GS} = 5V\)
- \(V_{DS} = -V_{GS(off)}\)
# Output Characteristics:
- \(V_{GS} = 0V\)
- \(V_{DS} = -V_{GS(off)}\)
# Off-State Region: \(V_{GS} < V_{GS(off)}\), \(0 < V_{DS} < V_{GS} - V_{GS(off)}\)
# On-State Region: \(V_{GS} > V_{GS(off)}\), \(0 < V_{DS} < V_{GS} - V_{GS(off)}\)
# Drain Current: \(i_D = \frac{k}{2} \frac{W}{L} [2(V_{GS} - V_{GS(off)})V_{DS} - V_{DS}^2]\) or \(i_D = \frac{k}{2} \frac{W}{L} [2(V_{GS} - V_{GS(off)})V_{DS} - V_{DS}^2]\)
# Saturation Region: \(i_D = \frac{k}{2} \frac{W}{L} (V_{GS} - V_{GS(off)})^2 (1 + \frac{V_{DS}}{V_A})\) or \(i_D = \frac{k}{2} \frac{W}{L} (V_{GS} - V_{GS(off)})^2 (1 + \frac{V_{DS}}{V_A})\)
Page 79
No.
Date
When Vgs=0, S and D between the conducting channel is the widest, G and S between the PN junction space charge region is the narrowest. At this time, adding Vgs can make it conduct.
When Vgs<0, the two p+ N junction space charge regions widen (mainly expanding towards the N region), the channel becomes wider. The channel resistance increases. When Vgs increases to Vgs(off), the channel is cut off, and the channel resistance is very high. At this time, adding Vgs, I0 is 0.
When Vgs
When Vgs=0 (Vgs(off)
When Vgs>0, a drain current ID is generated, flowing from the drain to the source. The voltage from the source to the drain is high. Therefore, the space charge region near the drain becomes wider, the channel becomes wedge-shaped, and the channel resistance increases.
When Vgs>Vgs(off), from the pre-cut to the cut-off, the cut-off point moves towards the source.
The voltage Vbc on the cut-off region is Vgs-(Vgs-Vgs(off)).
The voltage Vcs from the source to the cut-off point remains unchanged.
Channel length modulation effect: when Vgs increases, Vcs remains unchanged, but the channel length slightly decreases, so the channel resistance decreases, and I0 slightly increases.
JFET model:
$$
\begin{aligned}
& C_{gd}, C_{gs}: When the PN junction is reverse-biased, it is mainly the potential capacitance \\
& r_{dd} : Drain body resistance \\
& r_{ss} : Source body resistance \\
& i_{D} : Current-controlled current source \\
\end{aligned}
$$
Page 80
Field-Effect Transistor (FET) Application Principles
# Saturation Region: Voltage-Controlled Current Source
# Variable Resistance Region, Cutoff Region: Controlled Electronic Switch
# 1. FET Amplifier Circuit
$$
V_{GS} = V_{GSQ}
$$
$$
I_D = \frac{K}{2} \frac{W}{L} (V_{GS} - V_{GSQ})^2
$$
$$
V_{DS} = V_{DD} - R_D I_D
$$
# Output DC Operating Point (I_DQ, V_DSQ).
On the transfer characteristic curve (I_D - V_{GS}), within the signal \( V_S = V_{Sm} \sin \omega t \) range, the FET can be considered a linear element, with the operating point Q's slope being the transconductance \( g_m \).
- Drain signal current \( i_d = g_m V_S = g_m V_{Sm} \sin \omega t \)
- Total drain current \( I_D = I_{DQ} + g_m V_{Sm} \sin \omega t \)
- \( V_O = V_{DD} - R_D i_D = (V_{DD} - R_D I_{DQ}) - g_m R_D V_{Sm} \sin \omega t = V_{DSQ} + v_o \)
- Output AC signal voltage \( v_o = - g_m R_D V_{Sm} \sin \omega t \)
- Voltage gain \( A_v = \frac{V_o}{V_S} = - g_m R_D \)
# 2. FET Switching Circuit
If the input signal \( V_S \) is a large amplitude pulse signal, with low level \( V_{L} < V_{GSQ} \), and high level \( V_{H} \) is sufficiently large, then the MOSFET will operate in the cutoff region and the variable resistance region.
Page 81
**Electronic Circuit Experiment**
**Semiconductor Device Basics - Summary**
I. Semiconductor Bipolar Transistor
1. **Intrinsic Generation (Proportional to Temperature)**
- **Intrinsic Semiconductors (n_i = p_i)**: Two types of carriers.
- **Dynamic Equilibrium (Generation = Recombination)**: \( n_i = p_i = A_0 T^{\frac{3}{2}} e^{-\frac{E_g}{2kT}} \). \( T \uparrow, n_i \uparrow \)
- **For Silicon**: \( A_0 \approx 3.84 \times 10^{16} \, (\text{cm}^3 \cdot \text{K}^{\frac{3}{2}}) \), **Correction**: \( A_0 \approx 1.76 \times 10^{16} \, (\text{cm}^3 \cdot \text{K}^{\frac{3}{2}}) \)
- **\( E_g \)**: \( T = 0 \, \text{K} \) when the band gap (the energy required for electrons to break free from the valence band) is the smallest energy.
- **Silicon**: \( E_g = 1.21 \, \text{eV} \), **Correction**: \( E_g = 0.785 \, \text{eV} \)
- **At \( T = 300 \, \text{K} \)**: Silicon \( n_i = p_i \approx 1.43 \times 10^{10} \, \text{cm}^{-3} \), **Correction**: \( n_i = p_i \approx 2.38 \times 10^{13} \, \text{cm}^{-3} \).
- **Intrinsic Semiconductors have low conductivity**.
2. **Doping Elements**
- **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **Doping Elements** → **
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No.
Date
T = 300K, 硅的迁移率大. Ge比Si的迁移率大. 硅子比空穴迁移率大.
I = In + Ip = qS (-nUn + pUp)
= qS (nμnE + pμpE)
= qSE (nμn + pμp)
= qS·V (nμn + pμp)
∴ R = V / I = 1 / S · q(nμn + pμp) = φ L / S. ∴ σ = q(nμn + pμp).
余渍 { N型: σ ≈ qN0μn. (n >> p) T↑, μn↑, σ↑
P型: σ ≈ qN0μp. (p >> n) T↑, μp↑, σ↑
本征 { T↑, μn↑, μp↑, P↑↑↑, ∴ σ↑ -- N型.
T↑, μn↑, μp↑, P↑↑↑, ∴ σ↑ -- P型.
4. 扩散运动.
电子扩散 In = qSDn · d(nex) / dx. Dn 电子扩散系数. T↑, Dn↑
T = 300K, 硅的 Dn = 34. 错 Dn = 99.
空穴扩散 Ip = -qSDp · d(pex) / dx. Dp 空穴扩散系数. T↑, Dp↑
T = 300K, 硅的 Dp = 13. 错 Dp = 47.
∴ Ge比Si 扩散系数大. 电子比空穴扩散系数大.
Dp / μp = Dn / μn = kT / q.
5. PN结.
多子扩散 → 到对方区域复合. 自己区域留下不能移动离子 →
空间电荷区(阻挡层、耗尽层、势垒区) → 内建电场 → 漂移电流
→ 漂移与扩散动态平衡 → 空间电荷区:高阻区(n-P结低)。
Page 83
N-region, P-region: low resistance (thermal equilibrium, electrical neutrality).
Contact potential difference \( V_{\phi} = \frac{kT}{q} \ln \frac{N_{A}N_{D}}{N_{A}^{2}} \), \( V_{T} = \frac{kT}{q} \approx 26 \text{mV} \) (T = 300K).
\( T \uparrow \), \( n^{2} \uparrow \), \( V_{\phi} \downarrow \), \( (T - T_{0}) \cdot (2 \sim 2.5 \text{mV}) = (V - V_{\phi}) \)
\( T = 300 \text{K} \), silicon \( V_{\phi} \approx 0.5 \sim 0.7 \text{V} \), germanium \( V_{\phi} \approx 0.2 \sim 0.3 \text{V} \)
Barrier width \( W_{0} = W_{n} + W_{p} = \sqrt{\frac{2 \varepsilon}{q}} V_{\phi} \cdot \frac{N_{A} + N_{D}}{N_{A}N_{D}} \), \( T \uparrow \), \( V_{\phi} \downarrow \), \( W_{0} \downarrow \)
\(\because N_{A} \text{-side barrier charge} Q_{+} = q \cdot W_{n} \cdot N_{D} \)
\(\text{P-region barrier charge} Q_{-} = -q \cdot W_{p} \cdot N_{A} \)
\(\therefore Q_{+} = -Q_{-}\)
\(\therefore \frac{W_{n}}{W_{p}} = \frac{N_{A}}{N_{D}}\), i.e., the ratio of the doping concentration. The side with the wider barrier width decreases.
Solve to get \( W_{n} = N_{A} \sqrt{\frac{2 \varepsilon}{q}} \cdot \frac{V_{\phi}}{N_{A}N_{D}(N_{A} + N_{D})} \), \( N_{D} \downarrow \), \( W_{n} \downarrow \)
\( W_{p} = N_{D} \sqrt{\frac{2 \varepsilon}{q}} \cdot \frac{V_{\phi}}{N_{A}N_{D}(N_{A} + N_{D})} \), \( N_{A} \uparrow \), \( W_{p} \downarrow \)
PN junction forward characteristic: external voltage opposite to the contact potential difference direction, \( V_{\phi} \downarrow \), \( Q \downarrow \), \( W_{n}, W_{p} \downarrow \)
\(\rightarrow\) diffusion motion strengthens \(\rightarrow\) barrier layer on both sides of the junction increases (minority carriers)
\(\{ n_{p}(W_{p}) = n_{p_{0}} e^{\frac{qV_{\phi}}{kT}}, n_{p}(x) = [n_{p}(W_{p}) - n_{p_{0}}] e^{\frac{qV_{\phi}}{kT}} + n_{p_{0}} \}
\(\{ p_{n}(W_{n}) = p_{n_{0}} e^{\frac{qV_{\phi}}{kT}}, p_{n}(x) = [p_{n}(W_{n}) - p_{n_{0}}] e^{\frac{-qV_{\phi}}{kT}} + p_{n_{0}} \)
\(\rightarrow\) diffusion current > drift current, and carriers are continuously replenished
\(\rightarrow\) forms a closed circuit.
\(\therefore T \uparrow \), external voltage \( V_{\phi} \downarrow \), diffusion motion \(\uparrow\), forward current \(\uparrow\).
PN junction reverse characteristic: external voltage in the same direction as the contact potential difference, \( V_{\phi} \uparrow \), \( Q \uparrow \), \( W_{n}, W_{p} \uparrow \)
\(\rightarrow\) drift motion strengthens, while minority carriers (drift motion carriers) are few \(\rightarrow\)
\(\rightarrow\) drift motion strengthens, while minority carriers (drift motion carriers) are few \(\rightarrow\)
\(\rightarrow\) reverse current is small: silicon reverse current \( 10^{-6} \sim 10^{-9} \text{A} \), germanium reverse current \( 10^{-6} \sim 10^{-9} \text{A} \).
Page 84
T increases, minority carrier concentration increases, reverse current increases → I_s
P^+ N junction with forward bias
P^+ N junction with reverse bias
Current equation: I = I_s (e^(qV/kt) - 1)
V >> V_0 when I ≈ I_s e^(qV/kt); V << -V_0 when I ≈ -I_s
Assume V > V_0 when PN junction is conducting; V < V_0 when PN junction is cut off
V_0: 0.6~0.7V; Reverse V_0: 0.2~0.3V
Temperature characteristics: Forward bias, T increases, V decreases, diffusion increases, forward current increases (as described before)
Or T increases, V decreases, I_s increases, forward current increases.
(T - T_0) (2~2.5 mV) = -(V - V_0)
Reverse bias, T increases, minority carrier concentration increases, I_s increases (as described before)
I - I_0 = log_2 (I / I_0)
Reverse breakdown characteristics:齐穿, space charge region field strength increases → space charge region atoms' valence electrons are pulled out → field emission breakdown.
{Doping concentration increases, space charge region W decreases, E increases (reverse voltage < 6V)
T decreases, space charge region W increases, V(BR) decreases
Snow avalanche breakdown, space charge region field strength increases → space charge region atoms' valence electrons are pulled out → field emission breakdown.
{Doping concentration decreases, space charge region W increases, E decreases (reverse voltage > 6V)
T increases, μ_n μ_p decreases, drift velocity decreases, V(BR) increases (reverse voltage > 6V)
}
Page 85
Capacitance effect: Potential barrier, reverse voltage increases, space charge region W increases, Q+ and Q- increase → charging. Reverse voltage decreases, space charge region W decreases, Q+ and Q- decrease → discharging. C_T = dQ/dV = C_TO / (1 - V/V_T)^n = εS/W_0 (SS is proportional, W_0 is the initial width of the space charge region).
Diffusion capacitance, forward voltage increases, potential barrier两侧 minority carrier density increases (diffusion motion) → charging. Forward voltage decreases, potential barrier两侧 minority carrier density decreases (diffusion motion) → discharging. C_D = dQ/dV ≈ ∆Qn/∆V + ∆Qp/∆V.
C_T and C_D are in parallel. PN junction total capacitance C_J = C_T + C_D. The actual PN junction is an ideal PN junction C_J in parallel.
6. Semiconductor diode
In a diode, n_i is large, so V_F = kT/q * N_A * N_D / n_i is smaller than in a silicon diode; but because n_i is large, so I_S is larger than in a silicon diode; but because the diode V_F is small, so W is small, so the absolute value of V_F is small.
Static resistance: R_D = V_F / I_DQ
Dynamic resistance: r_d = dV / dI_D = V_F / I_DQ ≈ V_F / I_DQ ≈ 26(mV) / I_DQ(mA) (T = 300K)
Analysis method: Graphical method (find the intersection of the characteristic curve and the working characteristic line), equivalent circuit method (consider the situation of V_F and I_F), small signal method (find the static resistance at the working point, use dynamic resistance to find the small signal quantity, and remove the DC power supply).
Application example: Rectification (unidirectional conductivity), voltage stabilization (using the breakdown voltage V_0 = 6V, the voltage remains constant, I_min < I_2 < I_max).
Page 86
Bipolar Transistor
1. **NPN Example**:
- **Emitter Region**: N-type, high doping, low base width.
- **Collector Region**: N-type, low doping, small base width.
- **Base Region**: P-type, small width.
- **Assume B and E are forward biased, C and B are reverse biased**:
$$ I_{E} = I_{E_{n}} + I_{E_{p}} $$
$$ I_{B} = I_{B_{p}} + I_{E_{p}} - I_{C_{B_{0}}} = I_{B_{p}} + I_{E_{p}} - I_{C_{B_{0}}} $$
$$ I_{C} = I_{C_{n}} + I_{C_{B_{0}}} = I_{C_{n}} + I_{C_{B_{0}}} $$
$$ I_{E} = I_{C} + I_{B} $$
- **Current Definitions**:
- $$ \alpha = \frac{I_{C_{n}}}{I_{E}} $$: Common base current amplification factor, typical value 0.95~0.995.
- $$ I_{C} = \alpha I_{E} + I_{C_{B_{0}}} \approx \alpha I_{E} $$
- $$ \beta = \frac{I_{C_{n}}}{I_{E} - I_{C_{n}}} $$: Common emitter current amplification factor, typical value several hundred.
- $$ I_{C} = \beta I_{B} + (\beta + 1) I_{C_{B_{0}}} = \beta I_{B} + I_{C_{B_{0}}} \approx \beta I_{B} $$
- **Collector Current in Common Emitter Configuration**:
$$ I_{E} = (\beta + 1) I_{B} + I_{C_{B_{0}}} = (\beta + 1) (I_{B} + I_{C_{B_{0}}}) $$
Page 87
The input characteristic \( I_B = f(V_{BE}) \) | \( V_{CE} = \text{const.} \)
When \( V_{CE} \) increases, \( I_B \) decreases. \( V_{BE} \) remains constant. \( I_C \) decreases. \( I_E \) decreases. This is the base width modulation effect. Near the saturation region, the input characteristic is linear.
The output characteristic \( I_C = f(V_{CE}) \) | \( I_B = \text{const.} \)
When \( V_{CE} \) increases, \( I_C \) increases. \( I_B \) remains constant. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \( I_E \) increases. \( I_C \) increases. \(
Page 88
T $\uparrow$, VBE $\downarrow$ (IB = const) (as previously discussed), (T - T0) (2~2.5 mV) = - (VBE - VBE0)
T $\uparrow$, C region Pi $\uparrow$, IcB0 $\uparrow$
T $\uparrow$, Dn $\downarrow$, base region recombination $\downarrow$, IB $\downarrow$, $\overline{\beta}$ $\uparrow$, IcB0 $\uparrow$, $\frac{1}{\beta}$ $\frac{d\overline{\beta}}{dT}$ = 0.5%~1%, $\gamma$C
Therefore, when the temperature increases, the input characteristic curve shifts left, and the output characteristic curve shifts up.
3. Limit Parameters
As previously discussed, when iB increases to a certain extent, $\beta$ will significantly decrease. The corresponding collector current at the highest $\beta$ value is Icm.
V(BR)CEO: Emitter open circuit collector reverse breakdown voltage. Usually several volts.
V(BR)EBO: Collector open circuit emitter reverse breakdown voltage. Usually several volts.
V(BR)CEO: Base open circuit (iB = 0) collector and emitter reverse breakdown voltage.
V(BR)CEO > V(BR)CEO > V(BR)EBO. T $\uparrow$, V(BR)CEO $\uparrow$, V(BR)CEO $\uparrow$, V(BR)EBO $\downarrow$
Collector maximum allowable power dissipation Pcm:
$$
Pc = Vce \cdot Ic
$$
4. Application Examples
Amplification (properly set VBB, VEE bias to start in the amplification region. VBE, IB, IC, VCE (V0) waveforms are all composed of DC operating points and small signal components).
Switching (input low level, V0 x Vcc; input high level, working in the saturation state, V0 = VCE(sat)).
Judgment method: IB > IC / β: saturation; IB < IC / β: amplification; IB = 0, VCE = VEE: cutoff.
Page 89
III. FET Characteristics
| Name | N-Channel | P-Channel |
|------|----------|----------|
| Circuit Symbol | $G_{n}$ | $G_{p}$ |
| Variable Region Conditions | $V_{gs} > V_{gs(th)} > 0$ | $V_{gs} > V_{gs(th)}$ | $V_{gs} < V_{gs(th)} < 0$ | $V_{gs} < V_{gs(th)}$ |
| | $0 < V_{ds} < V_{gs} - V_{ds}$ | $0 < V_{ds} < V_{gs} - V_{ds}$ | $V_{gs} - V_{ds} < V_{ds} < 0$ | $V_{gs} - V_{ds} < V_{ds} < 0$ |
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Page 90
Four. Junction Field-Effect Transistor
| Name | N-channel JFET | P-channel JFET |
|------|----------------|---------------|
| Circuit Symbol | $$G \rightarrow S$$ | $$G \leftarrow S$$ |
| **Bias Region** | | |
| | Bias Condition | $$0 > V_{gs} > V_{gs(off)}$$ | $$0 < V_{gs} < V_{gs(off)}$$ |
| | | $$V_{gs} - V_{gs(off)} < V_{ds} < 0$$ |
| | Current Equation | $$i_{d} = \frac{k}{2} \frac{W}{L} [2(V_{gs} - V_{gs(off)})V_{ds} - V_{ds}^2]$$ | $$i_{d} = \frac{k}{2} \frac{W}{L} [2(V_{gs} - V_{gs(off)})V_{ds} - V_{ds}^2]$$ |
| **Saturation Region** | | |
| | Bias Condition | $$0 > V_{gs} > V_{gs(off)}$$ | $$0 < V_{gs} < V_{gs(off)}$$ |
| | | $$V_{ds} > V_{gs} - V_{gs(off)} > 0$$ | $$V_{ds} < V_{gs} - V_{gs(off)} < 0$$ |
| | Current Equation | $$i_{d} = \frac{k}{2} \frac{W}{L} [V_{gs} - V_{gs(off)}]^2 (1 + \frac{V_{ds}}{V_{A}})$$ | $$i_{d} = \frac{k}{2} \frac{W}{L} [V_{gs} - V_{gs(off)}]^2 (1 + \frac{V_{ds}}{V_{A}})$$ |
| **Transfer Characteristics** | | |
| | |
|
|
| **Output Characteristics** | | |
Page 91
Electronic Circuit Experiment: Instruments
# 1. Common Basic Electrical Quantities and Circuit Parameter Measurement Methods
1. **Voltage Measurement**
- **Amplitude**: μV~mV: Digital voltmeter, transistor voltmeter; mV~mV: Oscilloscope, digital voltmeter.
- **Frequency**: DC measurement: Digital voltmeter; AC circuit frequency measurement: Oscilloscope, high-frequency voltmeter.
- **Waveform**: Many AC voltmeters are designed for AC waveforms; oscilloscopes can measure DC bias voltage values.
- **Impedance**: The internal resistance of the voltmeter must be much greater than the equivalent resistance of the circuit being measured; usually, the circuit resistance is measured in parallel.
2. **Input Resistance and Output Resistance Measurement**
- **Input**: \( R_i = \frac{V_{out}}{I_{out}} = \frac{V_i}{V_i - V_o} R_i \) \( R_i \) and \( R_i \) are close when the error is small.
- **Output**: \( R_o = \frac{V_{out}}{I_{out}} = \left( \frac{V_o}{V_i} - 1 \right) R_i \) \( R_i \) and \( R_o \) are close when the error is small.
3. **Voltage Gain and Frequency Characteristics Measurement**
- **Gain**: \( A_v = \frac{V_o}{V_i} \)
- **\( A_v(f) \) = \( A_v(f) \) < \( \varphi(f) \) , \( A_v(f) \): mid-frequency characteristic, \( \varphi(f) \): phase characteristic.**
**Amplitude-Frequency Characteristics Measurement**: \( A_v(f) \)
- **\( A_v(f) \)**: \( A_v(f) \) is the amplitude-frequency characteristic curve.
- **\( \varphi(f) \)**: \( \varphi(f) \) is the phase-frequency characteristic curve.
- **Frequency sweep method**: Maintain the original input voltage amplitude unchanged, change the signal frequency, and use an oscilloscope or millivoltmeter to measure the change.
- **Frequency sweep method**: Use a frequency analyzer + oscilloscope to draw the amplitude-frequency characteristic curve.
Page 92
No.
Date
**Section 2: SS7804 Type Oscilloscope**
1. **Screen Display Adjustment Section**
- **① Power Switch (POWER)**
- **② Brightness Adjustment Knob/Beam Switch (INTEN/BEAM):** Adjusts brightness.
- **③ Screen Readout Brightness Adjustment Knob/Switch (READOUT/ON/OFF):** Adjusts brightness and turns on/off the screen text.
- **④ Focus Knob (FOCUS):** Makes the waveform clearer.
- **⑤ Trace Rotation Adjustment Knob (TRACE ROTATION):** Adjusts the trace level.
- **⑥ Scale Brightness Adjustment (SCALE):** Adjusts the brightness of the scale.
- **⑦ Output Calibration Signal (CAL):** Outputs a peak value of 0.6V, frequency 1kHz square wave.
- **⑧ Ground Terminal:**
2. **Y-axis Adjustment Section**
- **① Signal Output x2 (CH1 or CH2):** Input resistance 1MΩ, input capacitance 25pF.
- **② Channel Selection (CH1 or CH2):** CH1/CH2/dual trace.
- **③ Sensitivity Adjustment (VOLT DIV VARIABLE):** Fine and coarse adjustment, readable values; press to adjust.
- **④ Y-axis Position x2 (POSITION):** Adjusts up and down.
- **⑤ Input Coupling x2 (DC/AC):** DC coupling: DC + AC; AC coupling: AC only.
- **⑥ Ground (GND):** Use the zero voltage method (best to use a probe and ground shorting method to zero).
- **⑦ Signal Add (ADD):** Displays CH1, CH2, CH1 + CH2 (waveform).
- **⑧ Invert (INV):** -CH2. When using ADD, CH1 - CH2.
- **⑨ External Trigger Input (EXT TRIG):** Select external trigger input when triggering externally.
3. **X-axis Adjustment Section**
Page 93
1. Time selection knob (TIME/DIV VARIABLE): Rotate knob to read value; press down to display '>', not readable.
2. X-axis position (POSITION): Adjust left and right.
3. Scan mode (ALT CHOP): Alternating scan: high frequency; continuous scan: low frequency.
4. Scan extension (MAG x10): Each division becomes 1/10 of the original (time).
5. Horizontal position fine (FINE): Used for POSITION adjustment.
6. Trigger source selection (SOURCE): CH1/CH2/LINE (50Hz power supply)/EXT (external trigger). If there are two signals, choose the longer one.
7. Coupling mode selection (COUP): AC/DC/HF-R (high frequency)/LF-R (low frequency).
8. Trigger edge selection (SLOPE): +: rising edge; -: falling edge.
9. Trigger level selection (TRIG LEVEL): Trigger signal has no phase, waveform is stable.
10. TV (Trigger level is not fixed) (Trigger signal is not fixed)
11. Automatic scan (AUTO): Has a trigger signal, suitable for > 50Hz signals.
12. Normal scan (NORM): No trigger signal, suitable for < 50Hz signals.
13. Single scan (SGL/RST): Scan once, trigger once.
14. Normal display (X-T, A): Internal generated signal display. Horizontal time, AC and DC voltage.
15. X-Y display (X-Y): CH1 to X-axis, CH1/CH2/CH1+CH2 to Y-axis.
16. Fine adjustment (AV-at-off): AV (horizontal), at (vertical), close fine adjustment.
17. Fine adjustment (TCR/C2): Fine adjustment.
18. Function coarse (FUNCTION COARSE): Rotate coarse adjustment, fast movement.
19. Hold mode (HOLD OFF): Hold mode function, use the position adjustment knob.
Page 94
4. Measure DC Voltage.
In the screen, show the baseline and trace line, align the two cursors, and the bottom of the screen will display.
5. Measure AC Voltage Peak.
In the screen, show the stable waveform, align the two cursors up and down, and the bottom of the screen will display.
6. Phase Measurement.
Use the two cursors to pass through the two signals' zero points, read out Δt. Phase difference Δθ = Δt * 2π.
7. Time Measurement.
Period (T), pulse width, rise time (10% Vm ~ 90% Vm), fall time (vice versa).
8. Frequency Measurement.
Use CRT to read out (1/f); the bottom of the screen will display the frequency of the signal source (CH1/CH2) in the channel.
III. EE1642B1 Type Function Signal Generator.
1. Frequency Display.
2. Amplitude Display (not using the oscilloscope): 50V peak-to-peak.
3. Change the internal scan range (WIDTH).
4. Change the internal scan time duration (RATE).
5. External input socket (INPUT).
6. TTL Signal Output: Output standard TTL pulse signal, output impedance 600Ω.
7. Function Signal Output: ~, ~, ~, ~, ~, ~, ~.
8. Output Amplitude Adjustment (APM): Range 20dB.
9. DC Offset Adjustment (OFFSET): -5V to +5V (50V full scale), OFF is off.
10. Symmetry Adjustment (SYM): 50% duty cycle, OFF is 50% duty cycle (1/2).
11. Output Amplitude Attenuation (ATT): 20dB, 40dB, (20+40)dB, 0dB attenuation.
12. Selection Switch: ~, ~, ~.
Page 95
Experiment: Common Electronic Instrument Usage and Two-Port Network Parameter Measurement Methods
1. Pulse Width: \( V_m \) (from the vernier scale)
2. Average Width: \( t_w \) (from the vernier scale at the 50% rise and fall time points)
3. Period \( T \) (from the vernier scale at the pulse corresponding points)
4. Rise Time \( t_r \) (\( 0.1V_m \sim 0.9V_m \))
5. Fall Time \( t_f \) (\( 0.9V_m \sim 0.1V_m \))
6. Duty Cycle \( D \) (\( \frac{t_r}{T} \))
7. Phase Difference \( \Delta \phi = \frac{4T}{\pi} \cdot 2\pi \)
Page 1
**Mathematical Amplifier Circuit**
**A. Amplifier Circuit Main Performance Indicators**
**1. Static Circuit Analysis**
**a. Input Impedance**
$$ z_i = \frac{V_i}{I_i} \text{ Midband } R_i = \frac{V_i}{I_i} $$
**b. Output Impedance**
$$ z_o = \frac{V_o - V_i}{I_o} \text{ Midband } V_o = \frac{R_2}{R_1 + R_2} V_i $$
**c. Gain**
$$ \text{Voltage Gain } A_v = \frac{V_o}{V_i} \text{ Current Gain } A_i = \frac{I_o}{I_i} $$
**d. Frequency Response**
$$ A_v = A_v(\omega) = e^{j\varphi(\omega)} $$
**2. Dynamic Circuit Analysis**
**a. Input Characteristics**
**b. Output Characteristics**
**c. Distortion**
$$ \text{Maximum Dynamic Range: } V_{om1} = V_{ceq} - V_{cesat} $$
$$ V_{om2} = \text{DC Load Line Slope} \cdot I_{ce} $$
**d. Power Gain**
$$ \text{Power Gain } A_p = \frac{P_o}{P_i} = \frac{V_o^2}{V_i^2} $$
**e. Efficiency**
$$ \eta = \frac{P_o}{P_dc} \text{ DC Power Supply Average Power} $$
**f. Frequency Response**
$$ A_v(\omega) = \frac{1}{R_1 + R_2} \rightarrow f_1 - f_2 \text{ Bandwidth} $$
**g. Input Resistance**
$$ R_i \gg R_s, R_o \ll R_2 $$
**h. Output Resistance**
$$ R_o \gg R_1, R_s \ll R_2 $$
**i. Voltage Gain**
$$ A_v = \frac{R_2}{R_1 + R_2} A_v $$
**j. Current Gain**
$$ A_i = \frac{R_2}{R_1 + R_2} A_i $$
**k. Power Gain**
$$ A_p = \frac{R_2}{R_1 + R_2} A_p $$
**l. Efficiency**
$$ \eta = \frac{P_o}{P_dc} \text{ DC Power Supply Average Power} $$
**m. Frequency Response**
$$ A_v(\omega) = \frac{1}{R_1 + R_2} \rightarrow f_1 - f_2 \text{ Bandwidth} $$
**n. Input Resistance**
$$ R_i \gg R_s, R_o \ll R_2 $$
**o. Output Resistance**
$$ R_o \gg R_1, R_s \ll R_2 $$
**p. Voltage Gain**
$$ A_v = \frac{R_2}{R_1 + R_2} A_v $$
**q. Current Gain**
$$ A_i = \frac{R_2}{R_1 + R_2} A_i $$
**r. Power Gain**
$$ A_p = \frac{R_2}{R_1 + R_2} A_p $$
**s. Efficiency**
$$ \eta = \frac{P_o}{P_dc} \text{ DC Power Supply Average Power} $$
**t. Frequency Response**
$$ A_v(\omega) = \frac{1}{R_1 + R_2} \rightarrow f_1 - f_2 \text{ Bandwidth} $$
**u. Input Resistance**
$$ R_i \gg R_s, R_o \ll R_2 $$
**v. Output Resistance**
$$ R_o \gg R_1, R_s \ll R_2 $$
**w. Voltage Gain**
$$ A_v = \frac{R_2}{R_1 + R_2} A_v $$
**x. Current Gain**
$$ A_i = \frac{R_2}{R_1 + R_2} A_i $$
**y. Power Gain**
$$ A_p = \frac{R_2}{R_1 + R_2} A_p $$
**z. Efficiency**
$$ \eta = \frac{P_o}{P_dc} \text{ DC Power Supply Average Power} $$
**aa. Frequency Response**
$$ A_v(\omega) = \frac{1}{R_1 + R_2} \rightarrow f_1 - f_2 \text{ Bandwidth} $$
**ab. Input Resistance**
$$ R_i \gg R_s, R_o \ll R_2 $$
**ac. Output Resistance**
$$ R_o \gg R_1, R_s \ll R_2 $$
**ad. Voltage Gain**
$$ A_v = \frac{R_2}{R_1 + R_2} A_v $$
**ae. Current Gain**
$$ A_i = \frac{R_2}{R_1 + R_2} A_i $$
**af. Power Gain**
$$ A_p = \frac{R_2}{R_1 + R_2} A_p $$
**ag. Efficiency**
$$ \eta = \frac{P_o}{P_dc} \text{ DC Power Supply Average Power} $$
**ah. Frequency Response**
$$ A_v(\omega) = \frac{1}{R_1 + R_2} \rightarrow f_1 - f_2 \text{ Bandwidth} $$
**ai. Input Resistance**
$$ R_i \gg R_s, R_o \ll R_2 $$
**aj. Output Resistance**
$$ R_o \gg R_1, R_s \ll R_2 $$
**ak. Voltage Gain**
$$ A_v = \frac{R_2}{R_1 + R_2} A_v $$
**al. Current Gain**
$$ A_i = \frac{R_2}{R_1 + R_2} A_i $$
**am. Power Gain**
$$ A_p = \frac{R_2}{R_1 + R_2} A_p $$
**an. Efficiency**
$$ \eta = \frac{P_o}{P_dc} \text{ DC Power Supply Average Power} $$
**ao. Frequency Response**
$$ A_v(\omega) = \frac{1}{R_1 + R_2} \rightarrow f_1 - f_2 \text{ Bandwidth} $$
**ap. Input Resistance**
$$ R_i \gg R_s, R_o \ll R_2 $$
**aq. Output Resistance**
$$ R_o \gg R_1, R_s \ll R_2 $$
**ar. Voltage Gain**
$$ A_v = \frac{R_2}{R_1 + R_2} A_v $$
**as. Current Gain**
$$ A_i = \frac{R
Page 2
3. DC Load Line and AC Load Line
1) Basic Common Emitter Circuit
$$V_{CC} = V_{CEQ} + I_{CE} R_C$$ DC
$$V_{CE} = R_C I_C$$ AC
$$\therefore V_{CE} = V_{CE} + I_C R_C$$
2) RC Coupled Amplifier Circuit
$$V_{CC} = V_{CEQ} + I_{CE} R_C$$ DC
$$V_{CE} = (R_C // R_L) I_C$$ AC
$$\therefore V_{CE} = [V_{CEQ} + (R_C // R_L) I_C] - (R_C // R_L) I_C$$
4. Static Model Analysis
Assume base width modulation; VEE = const;
$$\overline{\beta} = \beta = const$$
B+ -> 2B
$$V_{BE} V_{th} = \frac{1}{2B} V_{CE}$$
5. Dynamic Model Analysis
Mixed Model: BJT in saturation region;
$$f < \frac{1}{3} f_T$$ Small signal
$$g_m V_{be} = \beta I_C$$
$$V_{be} r_{be} = C_{be}$$
$$V_{be} r_{be} = C_{be}$$
6. Stability of Operating Point
1) Importance of Operating Point Stability:
The dynamic performance indicators of the amplifier circuit are related to the operating point Q.
2) Main Factors Affecting Q Point Stability:
Temperature, power supply voltage, and transistor parameters.
3) Quasi-Static DC Operating Point Circuit:
4.1) When $$R_E' \gg 1 / (\omega C_{be})$$, ignore $$r_{be}$$
4.2) When $$\beta R_E \gg R_0$$, $$I_{CE} \approx \frac{V_{CC} - V_{BE}}{R_E}$$
4.3) When $$\beta R_E \gg R_0$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
4.4) When $$r_{be} \gg R_0$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
5.1) When $$R_{CE} \gg R_1$$, ignore $$r_{be}$$
5.2) When $$R_{CE} \gg R_1$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
5.3) When $$R_{CE} \gg R_1$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
5.4) When $$r_{be} \gg R_0$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
6.1) When $$R_{CE} \gg R_1$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
6.2) When $$R_{CE} \gg R_1$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
6.3) When $$R_{CE} \gg R_1$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
6.4) When $$r_{be} \gg R_0$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
6.5) When $$r_{be} \gg R_0$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
6.6) When $$r_{be} \gg R_0$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
6.7) When $$r_{be} \gg R_0$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
6.8) When $$r_{be} \gg R_0$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
6.9) When $$r_{be} \gg R_0$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
6.10) When $$r_{be} \gg R_0$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
6.11) When $$r_{be} \gg R_0$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
6.12) When $$r_{be} \gg R_0$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
6.13) When $$r_{be} \gg R_0$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
6.14) When $$r_{be} \gg R_0$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
6.15) When $$r_{be} \gg R_0$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
6.16) When $$r_{be} \gg R_0$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
6.17) When $$r_{be} \gg R_0$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
6.18) When $$r_{be} \gg R_0$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
6.19) When $$r_{be} \gg R_0$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
6.20) When $$r_{be} \gg R_0$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
6.21) When $$r_{be} \gg R_0$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
6.22) When $$r_{be} \gg R_0$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
6.23) When $$r_{be} \gg R_0$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
6.24) When $$r_{be} \gg R_0$$, $$A_V \approx -\frac{\beta R_C}{R_E}$$
6.25) When
Page 3
**II. Common Emitter Amplifier Circuit**
Output voltage from emitter - emitter follower. $I_{o} = \frac{1}{1+2\beta} I_{R}$. $I_{R} = \frac{V_{cc} - V_{BE}}{R_{e}}$. $R_{o} = R_{ce2}$.
$I_{o} \rightarrow 1$, $I_{R} \approx V_{i}$ - emitter follower. $\Delta$ Consider base width modulation:
$I_{o} = \frac{V_{i} + V_{ce2}}{V_{A} + V_{ce1}}$.
$\therefore I_{R} = 2I_{1} + 2I_{B1}$, ignore $I_{B3}$.
$\therefore \frac{I_{o}}{I_{R}} \approx \frac{V_{A} + V_{ce2}}{V_{A} + V_{ce1}}$.
Advantages: Simple, fewer components.
Disadvantages: The circuit's $R_{o}$ is not large, so $I_{o}$ is not small; $I_{o}$ is greatly influenced by $V_{cc}$; $R_{o}$ is not large enough; $V_{BE}$ and $R_{e}$ are sensitive to temperature.
Dynamic range analysis: $\because I_{E} \sim I_{C}$, $V_{cc} \sim V_{ce}$
$\because$ Using emitter output characteristic curve analysis.
Disadvantages: Pulse waveform distortion; self-oscillation.
**III. Common Base Amplifier Circuit**
Characteristics: Voltage gain (same phase), with base equal value. Input resistance low, output resistance high.
**IV. Current Source Circuit**
Using BJT as a current source:
$I_{o} = \frac{1}{1+2\beta R_{1}(\beta_{3}+1)} I_{R}$, $I_{R} = \frac{V_{cc} - 2V_{BE}}{R_{e}}$.
$R_{o} = R_{ce2}$
1. Basic Mirror Current Source
$I_{C1} = I_{C2}$, $\beta_{B1} = \beta_{B2}$.
$I_{C1} > I_{C2}$.
$\Delta$ Neglect base region width modulation:
$V_{BE1} = V_{BE2}$.
$I_{B1} = I_{B2} \rightarrow \beta_{B1} = \beta_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2}$.
$R_{B1} = R_{B2}$.
$I_{B1} = I_{B2
Page 4
2. Proportional Current Source
1) Negative Feedback Proportional Current Source
$$ Z_0 = (1 - \frac{2}{\beta + 2\beta + 2}) I_R, I_R = \frac{V_{CC} - 2V_{BE}}{R} $$
$$ R_0 \approx \frac{1}{2} (\beta + 1) R_{CE3} $$
$$ R_{E1} \neq R_{E2} $$
$$ I_0 \approx \frac{V_{BE1} - V_{BE2} + I_R R_{E1}}{R_{E2}} $$
$$ I_R R_{E1} \gg (V_{EE1} - V_{EE2}) $$
$$ I_0 \approx \frac{R_{E1}}{R_{E2}} I_R $$
$$ I_R = \frac{V_{CC} - V_{BE2} - V_{RE1}}{R} $$
$$ R_0 \approx R_{CE2} (1 + \frac{\beta R_{E2}}{R_{EE} + R_{B} + R_{E2}}) $$
2) Simple Proportional Current Source
$$ \frac{I_0}{I_R} \approx \frac{I_{E2}}{I_{E1}} \propto \frac{I_{E2} e^{V_{BE2}/V_T}}{I_{E1} e^{V_{BE1}/V_T}} $$
$$ = \frac{I_{E2}}{I_{E1}} = \frac{S_2}{S_1} $$
T1, T2 characteristics not equal.
3. Micropower Current Source
$$ I_0 \propto \frac{V_{T}}{R_{E}} \ln \frac{I_R}{I_0} $$
$$ I_R = \frac{V_{CC} - V_{BE1}}{R} $$
$$ V_{BE1} - V_{BE2} \approx V_T \ln \left( \frac{I_R}{I_0} \right) $$
$$ \propto V_T \ln \left( \frac{I_R}{I_0} \right) $$
4. Wilson Current Source
$$ I_0 \propto \frac{V_{T}}{R_{E}} \ln \frac{I_R}{I_0} $$
$$ I_R = \frac{V_{CC} - V_{BE1}}{R} $$
$$ \left\{ \begin{array}{l} V_{BE1} = V_{BE2} \\ 2I_1 = I_{B1} \\ 2I_2 = I_{B2} \\ R_1 = R_{BE1} \\ R_2 = R_{BE2} \\ R_0 = R_{CE1} // R_{CE2} \end{array} \right. $$
$$ \left\{ \begin{array}{l} A_V = - \frac{R_1 (R_{CE1} / R_{CE2})}{R_{BE1}} \\ R_1 = R_{BE1} \\ R_2 = R_{BE2} \\ R_0 = R_{CE1} // R_{CE2} \end{array} \right. $$
$$ \left\{ \begin{array}{l} A_V = - \frac{R_1 (R_{CE1} / R_{CE2})}{R_{BE1}} \\ R_1 = R_{BE1} \\ R_2 = R_{BE2} \\ R_0 = R_{CE1} // R_{CE2} \end{array} \right. $$
$$ \left\{ \begin{array}{l} A_V = - \frac{R_1 (R_{CE1} / R_{CE2})}{R_{BE1}} \\ R_1 = R_{BE1} \\ R_2 = R_{BE2} \\ R_0 = R_{CE1} // R_{CE2} \end{array} \right. $$
$$ \left\{ \begin{array}{l} A_V = - \frac{R_1 (R_{CE1} / R_{CE2})}{R_{BE1}} \\ R_1 = R_{BE1} \\ R_2 = R_{BE2} \\ R_0 = R_{CE1} // R_{CE2} \end{array} \right. $$
$$ \left\{ \begin{array}{l} A_V = - \frac{R_1 (R_{CE1} / R_{CE2})}{R_{BE1}} \\ R_1 = R_{BE1} \\ R_2 = R_{BE2} \\ R_0 = R_{CE1} // R_{CE2} \end{array} \right. $$
$$ \left\{ \begin{array}{l} A_V = - \frac{R_1 (R_{CE1} / R_{CE2})}{R_{BE1}} \\ R_1 = R_{BE1} \\ R_2 = R_{BE2} \\ R_0 = R_{CE1} // R_{CE2} \end{array} \right. $$
$$ \left\{ \begin{array}{l} A_V = - \frac{R_1 (R_{CE1} / R_{CE2})}{R_{BE1}} \\ R_1 = R_{BE1} \\ R_2 = R_{BE2} \\ R_0 = R_{CE1} // R_{CE2} \end{array} \right. $$
$$ \left\{ \begin{array}{l} A_V = - \frac{R_1 (R_{CE1} / R_{CE2})}{R_{BE1}} \\ R_1 = R_{BE1} \\ R_2 = R_{BE2} \\ R_0 = R_{CE1} // R_{CE2} \end{array} \right. $$
$$ \left\{ \begin{array}{l} A_V = - \frac{R_1 (R_{CE1} / R_{CE2})}{R_{BE1}} \\ R_1 = R_{BE1} \\ R_2 = R_{BE2} \\ R_0 = R_{CE1} // R_{CE2} \end{array} \right. $$
$$ \left\{ \begin{array}{l} A_V = - \frac{R_1 (R_{CE1} / R_{CE2})}{R_{BE1}} \\ R_1 = R_{BE1
Page 5
The page contains a detailed analysis of a differential amplifier circuit. It includes mathematical derivations and circuit diagrams. Here's the translated content:
---
**5. Differential Amplifier Circuit**
Let V1 and V2 be arbitrary amplitude and phase signals:
$$V_{o1} = \frac{1}{2}(V_{i1} + V_{i2}) + \frac{1}{2}(V_{i1} - V_{i2})$$
$$V_{o2} = \frac{1}{2}(V_{i1} + V_{i2}) - \frac{1}{2}(V_{i1} - V_{i2})$$
Common mode input signal: Vic = (V1 + V2) / 2
Differential mode input signal: Vid = V1 - V2
The circuit diagram shows a differential amplifier with two transistors T1 and T2, a voltage source Vcc, and resistors R1 and R2. The output is labeled as Vo1 and Vo2.
$$V_{cc}$$
$$V_{o1}$$
$$V_{o2}$$
$$R1$$
$$R2$$
$$V_{i1}$$
$$V_{i2}$$
**2. Dynamic Analysis: Large Signal State**
1) Differential mode:
- Function: Non-saturated switch (operating in the linear region)
- Limitation: Vcm = Vce + Vbrcebo
2) Common mode:
- Function: Collector voltage almost constant
- Limitation: Cannot drive BJT into saturation (Vcm).
**3. Dynamic Analysis: Small Signal State**
Aod: Differential mode voltage gain; Auc: Common mode voltage gain.
Vo = Vod + Voc = Aud Vid + Auc Vic
1) Differential mode:
- Double-ended output:
- Input circuit: Collector grounded
- Output circuit: R1 midpoint grounded
- Aud = Vo1 / Vid = (Vod1 - Vod2) / (Vi1 - Vi2) = 2Vod1 / 2Vi1 = -βRc / Rbe
- Rod = 2Rc, Rid = 2Rbe (with respect to ground)
- Single-ended output:
- Base width modulation. Assuming symmetry.
- Aud = -1/2 βRc / Rbe. If both sides are connected to ground Rc, Aud = -βRc / Rbe.
- Rod = Rc, Rid = 2Rbe.
2) Common mode:
- Double-ended output:
- Input circuit: Collector 2Rc feedback resistor. Single-ended analysis.
- Output circuit: R2 open circuit
- Roc = 2Rc, Ric = 1/2 (2Rc || Rc). Icc = Vcc / 2Rc
- Single-ended output:
- Base width modulation. Assuming symmetry.
- Aud = -βRc / Rbe. If both sides are connected to ground Rc, Aud = -βRc / Rbe.
- Rod = Rc, Rid = 2Rbe.
---
The page also includes a graph of Vo1 and Vo2 as a function of Vid. The graph shows a linear relationship between Vo1 and Vo2, with a slope of 1 and an intercept of 0.
Page 6
4. Active Load Differential Amplifier Analysis
1) Static Analysis: Symmetry, Current Source Analysis.
2) Dynamic Analysis (Small Signal, Linear Region):
5. Resistance Biasing and Current Source Biasing Issues
Current Source Biasing:
When adding a large common mode signal + common mode current,
the current through Rc remains unchanged. The circuit's voltage distribution is not affected.
Resistance biasing:
When there is no Lc, the current remains unchanged. The addition of common mode signal + common mode current (in the existing transistor model, only the common mode signal + common mode current can be analyzed. When analyzing the common mode signal + common mode current, the circuit's quantities have changed, and it needs to be solved again.)
① Differential Mode:
Single-ended output, with current source transmission effect.
The output terminal obtains a signal current that is twice the single-ended signal current, equal to the double-ended output current.
$$A_{vd} = \frac{\beta R_{L}'}{r_{be}}$$
$$R_{L}' = r_{ce2} // r_{ce1} // R_{L}$$
$$R_{id} = 2 r_{be1}$$
$$R_{o} = r_{ce2} // r_{ce1}$$
② Common Mode:
Common mode signal + common mode current + common mode voltage + common mode resistance.
The common mode current is the same as the double-ended output current.
The common mode voltage is the same as the double-ended output voltage.
The common mode resistance is the same as the double-ended output resistance.
Analysis Method: Common mode large signal → Vcm problem
Current source output resistance
Analysis Method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common mode large signal → Vcm problem
Current source output resistance
Common mode analysis method: Common
Page 7
**Six. Push-Pull Output Stage (Large Signal Analysis)**
**B. Class AB**
**Conduction Angle:** Half of the conduction angle of the transistor in one period of the signal.
- Class B: θ = 90°
- Class A: θ = 180°
- Class AB: θ ∈ (90°, 180°)
**C. Push-Pull Output Stage Output Power and Efficiency**
**Vom:** Output Voltage Amplitude
**Iom:** Output Current Amplitude
**Load Average Power:**
$$ P_0 = \frac{1}{2} \int_{0}^{2\pi} \left(\frac{V_{om} \sin(\omega t)}{R}\right)^2 d(\omega t) = \frac{1}{2} V_{om} I_{om} $$
**Power Supply Average Power:**
$$ P_{dc} = 2 \cdot \frac{1}{2\pi} \int_{0}^{\pi} V_{cc} I_{om} \sin(\omega t) d(\omega t) = \frac{2V_{cc}}{\pi} \frac{V_{om}}{R} $$
**Efficiency:**
$$ \eta = \frac{P_0}{P_{dc}} = \frac{\pi}{4} \frac{V_{om}}{V_{cc}} $$
**Transistor Total Power Consumption:**
$$ P_{dc} - P_0 = \frac{2V_{cc} V_{om}}{\pi R} - \frac{1}{2} \frac{V_{om}^2}{R} $$
If V_{o} can reach $\frac{2}{\pi} V_{cc}$, then the efficiency reaches its maximum value:
$$ P_{Tmax} = \frac{2}{\pi^2} \frac{V_{cc}^2}{R} $$
**D. Composite Transistor**
**Four Types of Connections:**
- NNEB
- PPEB
- NPEB
- PNEB
**Current Gain Factor:**
$$ \beta + \beta_1 (1 + \beta_1) (\alpha_1 + \beta_1 (\alpha_1) + \alpha_1 (\beta_1) - \alpha_1 (\beta_1 + 1)) $$
**Current Gain Factor:**
- NNEB: Same as input
- PPEB: Same as input
- NPEB: Same as input
- PNEB: Same as input
**Input Resistance:**
$$ R_{se1} + R_1 + R_{be2} + \ldots + R_{be1} + \ldots $$
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The page contains a series of handwritten notes and diagrams related to electronic circuits. Here's a breakdown of the content:
---
**Solution 1:**
The circuit diagram shows a common-emitter amplifier with a base resistor and a collector resistor. The formulas provided describe the output voltage (Vo) in terms of the supply voltage (Vcc), the base-emitter voltage (VBE), and the resistors (R1 and R2). The formulas are:
$$
V_{o} = V_{cc} - [R_{c}(i_{c3} + i_{B1}) + V_{BE1}]
$$
$$
V_{o} = V + R_{1}C_{1}R_{2}
$$
The output voltage Vo is derived as:
$$
V_{o} = \frac{V_{cc} - V_{BE1} - R_{c}i_{c3}}{1 + \frac{R_{c}}{(1 + \beta_{1})R_{2}}}
$$
When iB1 approaches zero, Vo simplifies to:
$$
V_{o} = \frac{V_{cc} - V_{BE1}}{1 + \frac{R_{c}}{(1 + \beta_{1})R_{2}}}
$$
The text discusses the static and dynamic behavior of the circuit, including the base currents and collector currents. It also mentions the use of diodes in the circuit for biasing purposes.
---
**Solution 2:**
The circuit diagram shows a different configuration, possibly a voltage follower or buffer stage. The formulas provided describe the output voltage (Vo) in terms of the supply voltage (Vcc) and the resistors (R1 and R2). The formulas are:
$$
V_{CEQ4} = V_{CEQ1} + V_{EBR2} \approx (1 + \frac{R_{1}}{R_{2}})V_{CEQ4}
$$
The text discusses the static and dynamic behavior of the circuit, including the base currents and collector currents. It also mentions the use of diodes in the circuit for biasing purposes.
---
**Solution 3:**
The circuit diagram shows a common-emitter amplifier with a base resistor and a collector resistor. The formulas provided describe the output voltage (Vo) in terms of the supply voltage (Vcc), the base-emitter voltage (VBE), and the resistors (R1 and R2). The formulas are:
$$
V_{o} = [R_{c}(i_{c3} + i_{B1}) + V_{BE1}] + V_{cc}
$$
The text discusses the static and dynamic behavior of the circuit, including the base currents and collector currents. It also mentions the use of diodes in the circuit for biasing purposes.
---
**Solution 4:**
The circuit diagram shows a common-emitter amplifier with a base resistor and a collector resistor. The formulas provided describe the output voltage (Vo) in terms of the supply voltage (Vcc), the base-emitter voltage (VBE), and the resistors (R1 and R2). The formulas are:
$$
V_{o} = [R_{c}(i_{c3} + i_{B1}) + V_{BE1}] + V_{cc}
$$
The text discusses the static and dynamic behavior of the circuit, including the base currents and collector currents. It also mentions the use of diodes in the circuit for biasing purposes.
Page 9
**Mathematical Note on Circuit Frequency Response**
**7. Amplifier Circuit Frequency Response Characteristics**
1. **Frequency Response Analysis Methods**
- **Small Signal Amplifier Circuit**:
- **Medium Frequency**: Linear time-invariant system.
- **Low Frequency**: Capacitors dominate.
- **High Frequency**: Capacitors dominate.
- **Zero State Condition**:
- \( V_R(t) = R_i i_R(t) \)
- \( V_L(t) = L \frac{di_L(t)}{dt} \)
- \( i_L = \frac{1}{L} \int_0^t i_C(t) dt \)
- **Laplace Transform**:
- \( V_R(s) = R_i i_R(s) \)
- \( V_L(s) = L \frac{di_L(s)}{ds} \)
- \( V_C(s) = \frac{1}{sC} i_C(s) \)
- **Element Model**: \( R \), \( sL \), \( \frac{1}{sC} \). All are real positive numbers.
- **Impulse Response**: \( h(t) = r(t) * e(t) \)
- \( R(s) = H(s) * E(s) \)
- \( H(s) = \frac{R(s)}{E(s)} \)
- **Steady State Model**: \( H(s) \) in the amplifier circuit is a general rational function. Further,
- \( H(s) = \frac{K \prod_{i=1}^n (s - z_i)}{\prod_{i=1}^n (s - p_i)} \)
- **Sinusoidal Input**: \( e(t) = E_m \sin(\omega_0 t) \)
- \( E(s) = \frac{E_m \omega_0}{s^2 + \omega_0^2} \)
- \( R(s) = \frac{E_m \omega_0}{s^2 + \omega_0^2} H(s) \)
- \( = \frac{K_1 \omega_0}{s + j \omega_0} + \frac{K_2 \omega_0}{s - j \omega_0} + \frac{K_3}{s - p_1} + \ldots + \frac{K_n}{s - p_n} \)
- **Among them**: \( K_{-j \omega_0} = (s + j \omega_0) R(s) \big|_{s = j \omega_0} = \frac{E_m \omega_0 H(j \omega_0)}{-2j \omega_0} \)
- \( K_{j \omega_0} = (s - j \omega_0) R(s) \big|_{s = j \omega_0} = \frac{E_m \omega_0 H(j \omega_0)}{2j \omega_0} \)
- **System Response**: \( h(t) = L^{-1}[R(s)] = E_m H_0 \sin(\omega_0 t + \varphi_0) \)
- \( + K_1 e^{p_1 t} + \ldots + K_n e^{p_n t} \)
- **When \( t \to \infty \)**:
- \( r(t) = E_m H_0 \sin(\omega_0 t + \varphi_0) \)
- **Based on the above, in the steady state, \( H(s) \) is equivalent to \( H(j \omega) \).**
- **Conclusion**: \( f_\alpha = (\beta_0 + 1) f_\beta = \frac{1}{2 \pi r_{be} (C_{be} + C_{bc})} \). \( f_\alpha > f_\beta > f_\beta \)
2. **BJT Amplifier Circuit Frequency Response**
- **Low, Medium, High Frequency Mixed Model**:
- \( \beta_0 \): Low frequency current amplification factor (emitter)
- \( \beta \): Common emitter output current amplification factor (collector)
- \( \alpha \): Low frequency current amplification factor (base)
- \( \alpha \): Common base output current amplification factor.
- \( f_\beta \): Frequency at which \(\beta\) drops to 1/2.
- \( f_T \): Frequency at which \(\beta = 1\), transistor characteristic frequency.
- \( f_2 = (\beta_0 + 1) - f_\beta \).
- **Range of Application**: \( f_\beta < f < f_T \).
shows a circuit diagram with labeled components such as \( V_{be} \), \( V_{re} \), \( C_{be} \), \( C_{re} \), \( r_{be} \), and \( r_{ce} \).
shows a circuit diagram with labeled components such as \( V_{be} \), \( V_{re} \), \( C_{be} \), \( C_{re} \), \( r_{be} \), and \( r_{ce} \).
Page 10
3. Linearity distortion:
- Amplitude distortion: no new frequency components
- Phase distortion: no new frequency components (maybe)
- Nonlinear distortion: produces new frequency components (maybe)
- Distortion transfer: H(t) ≠ Ke^(jωt) → H(jω) = Ke^(jωt)
- Bandwidth: midband gain Avsm - bandwidth BW.
4. Due to single-ended, common-emitter, and common-base configurations being approximately RC circuits, thus analyzing RC low-pass/high-pass filters:
$$ H(j\omega) = \frac{1}{1+j\frac{\omega}{\omega_{H}}} $$
$$ f_{H} = \frac{1}{2\pi RC} $$
$$ \therefore 20\lg|H| = -20\lg\sqrt{1+(\frac{\omega}{\omega_{H}})^2} $$
$$ \varphi = -\arctan(\frac{\omega}{\omega_{H}}) $$
$$ f = f_{H} \text{ at phase lag } 20\lg\sqrt{2} \approx 3\text{dB} $$
$$ f = 0.1f_{H} \text{ at phase lag } \arctan(0.1) \approx 5.7^\circ $$
$$ f = 10f_{H} \text{ at phase lag } \arctan(10) \approx -5.7^\circ $$
$$ H(j\omega) = \frac{j\frac{\omega}{\omega_{2}}}{1+j\frac{\omega}{\omega_{2}}} $$
$$ f_{2} = \frac{1}{2\pi RC} $$
$$ \therefore 20\lg|H| = 20\lg(\frac{\omega}{\omega_{2}}) - 20\lg\sqrt{1+(\frac{\omega}{\omega_{2}})^2} $$
$$ \varphi = -\arctan(\frac{\omega}{\omega_{2}}) + \frac{\pi}{2} $$
$$ f = f_{2} \text{ at phase lag } 20\lg\sqrt{2} \approx 3\text{dB} $$
$$ f = 0.1f_{2} \text{ at phase lag } \arctan(0.1) \approx 5.7^\circ $$
$$ f = 10f_{2} \text{ at phase lag } \arctan(10) \approx -5.7^\circ $$
5. Common-emitter high-frequency response (second-order to first-order zero):
Simplified steps: neglect Cb' → ignore Cb' → combine RsC
$$ A_{vs} = A_{vs} \frac{1}{1+j\frac{\omega}{\omega_{H}}} $$
$$ f_{H} = \frac{1}{2\pi R_{s}C} $$: Rs is the input resistance seen from Cb'.
$$ G \cdot BW = |A_{vs}| \cdot f_{H} $$, Rs, Cb', Cb'e, G, BW. fH↑
Note: To increase fH, Rs should be minimized → constant voltage excitation.
Common-base high-frequency response (second-order to first-order zero):
Simplified steps: include Cb' (ωCb' ≫ Rs + Rbb')
$$ A_{vs} = A_{vs} \frac{1+j\frac{\omega}{\omega_{2}}}{1+j\frac{\omega}{\omega_{p}}} $$
$$ f_{2} \approx f_{1}, f_{p} = \frac{1}{2\pi R_{s}C_{b'}} $$
$$ f_{p} = \frac{1}{2\pi R_{s}C_{b'}} $$: Rs is the input resistance seen from Cb'.
$$ f_{H} = \left(\frac{1}{f_{p}} - \frac{1}{f_{2}}\right)^{-1} $$: Rbb' ↓, Cb'e ↓, fH↑
Note: To increase fH, Rs should be minimized → constant voltage excitation. Cb'e's compensation current effect makes fH very large.
Common-base high-frequency response (second-order zero):
Simplified steps: neglect Rbb' → separate current source → equivalent source is 1/Sm
$$ A_{vs} = A_{vs} \frac{1}{1+j\frac{\omega}{\omega_{p}} \times 1+j\frac{\omega}{\omega_{p}}} $$
$$ f_{p1} = \frac{1}{2\pi (R_{s} \parallel R_{e})C_{b'}} $$: Rs || Re is the input resistance seen from Cb'.
$$ f_{p2} = \frac{1}{2\pi R_{s}C_{b'}} $$: Rs is the input resistance seen from Cb'.
$$ \frac{1}{f_{H}} \propto \sqrt{\frac{1}{f_{p1}} + \frac{1}{f_{p2}}} $$
Note: To increase fH, Rs should be minimized → constant voltage excitation. Avoid fH being too small, which would not be a capacitive load.
Summary: High-frequency section串联大电容旁路并联大电容旁路, short circuit all capacitors. Large short circuit capacitors, small long circuit capacitors. Calculate fH.
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6. Transistor low frequency response.
BJT internal capacitance small: Cbe 10 pF, Cbc 1 pF. Low frequency can be ignored. Generally, small capacitors are connected in series and parallel. Simplify the circuit: ignore bias resistor Rb, ignore Re. The emitter resistor is equivalent to the base circuit. Ignore Re. The base circuit combines C and the output circuit. The DC voltage source is ignored.
$$A_{vs} = A_{vs} \cdot \frac{jf/f_1}{1+jf/f_2} \cdot \frac{jf/f_2}{1+jf/f_2}$$
$$f_1 = \frac{1}{2\pi (R_S + R_{be})C} \cdot C \sim R_S + R_{be} (C \text{ very small})$$
$$f_2 = \frac{1}{2\pi (R_C + R_L)C} \cdot C \sim R_C + R_L$$
$$f_2 \approx \sqrt{f_1^2 + f_2^2} \text{. For small C1, C2, C3, f1 = 0 (direct coupling).}$$
Overall: Use superposition principle (resistive network) to determine the time constant. When the time constant is known, the other capacitors can be calculated one by one.
7. Multi-stage amplifier circuit frequency response
Low frequency response main factors: coupling capacitors, stray capacitance. High frequency response main factors: stray capacitance, distributed capacitance. Time constant method to analyze each capacitor's single action time constant T. If other T values are much different, it is a five-pole circuit, and the calculation is simplified. If other T values are similar, then T = √(Σf²). fH ≈ (1 - 1/Σf²)⁻¹
$$A_{V1} = -\frac{R_{R1}}{R_{be}} \approx -1 \text{ (R1' = Rbe/(β+1))}$$
$$A_{V2} = -\frac{R_{R2}}{R_{be}}$$
$$A_{V} = \frac{R_{R1}}{R_{be}}$$
$$R_1 = R_{be} \text{ (large)}$$
$$R_2 = R_{be} \text{ (large)}$$
$$R_0 = R_C$$
8. Multi-stage amplifier circuit
Capacitor coupling:
Not easy to integrate, low frequency response is poor; used as a coupling circuit.
Transformer coupling:
Large volume, low frequency response is poor. Used in high-power circuits.
Direct coupling:
Easy to integrate. f1 = 0; DC voltage offset problem, zero drift.
1. DC voltage offset problem.
① Base-emitter diode/constant current diode (static voltage drop small)
② Current source DC voltage shifting circuit (shifts 20R) high frequency point
③ NPN-PNP互补直流电压偏移电路.
2. Zero drift problem.
Zero point, working point.
Drift: Output voltage relative to the initial value randomly fluctuates.
Solution: Input offset compensation
3. Multi-stage amplifier circuit calculation method.
View the lower stage including the input resistance, view the upper stage including the output resistance.
1) CE-CB
$$R_0 = R_C$$
$$R_1 = R_{be} \text{ (large)}$$
$$R_2 = R_{be} \text{ (large)}$$
$$R_0 = R_C$$
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2) CC-CB.
$$A_{V1} = \frac{(\beta+1)R_{C1}}{r_{be1} + (\beta+1)R_{C1}} \approx \frac{1}{2} (R_{C1} = \frac{r_{be1}}{\beta+1})$$
$$A_{V2} = \frac{\beta R_{C1}}{r_{be1}}$$
$$A_{V} = \frac{\beta R_{C1}}{2 r_{be1}}$$
CC, CB的高频响应良好.
3) CC-CE.
$$A_{V1} = \frac{(\beta+1) r_{be2}}{r_{be1} + (\beta+1) r_{be2}}$$
$$A_{V2} = -\frac{\beta R_{C}}{r_{be2}}$$
$$A_{V} = -\frac{\beta (\beta+1) R_{C}}{r_{be1} + (\beta+1) r_{be2}}$$
$$R_{i} = r_{be1} + (\beta+1) r_{be2}$$
$$R_{o} = R_{C}$$
CC的输出阻抗小($\approx \frac{R_{C}}{\beta+1}$), 即CE的等效信号源内阻小, 恒压激励, fH提高.
4) CE-CB差放.
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**Subject:**
**Math Assignment**
**Number:**
**Class:**
**Name:**
**Page:**
**Section 9 - MOSFET Model**
1. **Static**
- **Variable Resistance Region:** \( I_D = \frac{K}{2} \frac{W}{L} [2(V_{GS} - V_{TH})V_{DS} - V_{DS}^2] \)
- **Saturation Region:** \( I_D = \frac{K}{2} \frac{W}{L} (V_{GS} - V_{TH})^2 (1 + \lambda V_{DS}) \)
2. **Low-Frequency Small Signal**
- \( g_m = \frac{\partial i_D}{\partial V_{GS}} = 2 \sqrt{\frac{K}{2}} \frac{W}{L} I_D \)
- \( g_{mb} = \eta g_m \)
- \( g_{ds} = \frac{1}{r_{ds}} = \frac{I_D}{V_A + V_{DS}} = \frac{\lambda I_D}{1 + \lambda V_{DS}} \)
3. **High-Frequency Small Signal**
- \( g_{gb} = g_{gd} \)
- \( g_{gs} = g_{gb} + g_{gs} \)
- \( g_{gd} = g_{bd} \)
- \( C_{gs} = C_{gb} + C_{gs} \)
- \( C_{gd} = C_{bd} \)
- \( C_{gd} = C_{bd} \)
- \( I_{D} = I_{S} \frac{g_{m}}{2 \pi (C_{gs} + C_{gd})} \)
4. **Three Basic Fixed Bias Circuits: R0 Fixed
**Section 10 - MOSFET with Active Resistor and Current Source**
1. **Active Resistor (Frequency)**
- **Enhancement Type: GD Shorted: Ensures Saturation Region**
- **DC:** \( R_0 = \frac{V_{DS}}{2 \alpha} \)
- **AC:** \( r = r_{ds} \parallel \frac{1}{g_m} \) (b-s shorted)
- **Depletion Type: GS Shorted: Ensures Saturation Region**
- **DC:** \( R_0 = \frac{V_{DS}}{2 \alpha} \)
- **AC:** \( r = r_{ds} \) (b-s shorted)
- **Application: Voltage Divider: Wide Input Range, Stable Characteristics**
- **Current Source (Frequency)**
- **Basic Current Source / Proportional Current Source**
- **Active Resistor Obtains Reference Current \( I_R \):** \( Z_0 = \left[ \frac{W_1}{L_1} \right] \left[ \frac{W_2}{L_2} \right] R_0 \)
- **Neglecting Channel Length Modulation:** \( Z_0 = \frac{W_1 L_2}{W_2 L_1} \left[ \frac{W_1}{L_1} \right] R_0 \)
- **Output Impedance:** \( R_0 = r_{ds} \)
- **Current Mirror / Proportional Current Source**
- **Feedback, Good Temperature Stability:** \( R_0 = (g_m r_{ds}) r_{ds} \)
- **In Reference Branch: Active Resistor \( T_4 \):** \( V_{DS4} = V_{SS3} \), Improves Accuracy
- **Deficiency:** Basic Current Source Dynamic Range Small (When \( V_{DS} \) is Large)
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3. Source Follower Amplifier Circuit
1. NMOS E/D
$$V_{2} = V_{bs1} > V_{th}$$
$$V_{0} = V_{bs1} > V_{bs1} - V_{th}$$
$$V_{DD} - V_{0} = V_{bs2} > -V_{off}$$
2. NMOS E/E
$$A_{V} = -g_{m1} \cdot (g_{ds1} + g_{ds2} + g_{mb2})^{-1} = -g_{m1} R_{o}$$
3. CMOS C/S
$$V_{2} = V_{bs1} > V_{th1}$$
$$V_{0} = V_{bs1} > V_{bs1} - V_{th1}$$
$$V_{bs1} - V_{DD} = V_{bs2} < V_{bs1} - V_{bs2}$$
4. Source Follower Amplifier Circuit
1. Low Frequency:
$$A_{V} = -g_{m1} \cdot (g_{ds1} + g_{ds2} + g_{mb2})^{-1} = -g_{m1} R_{o}$$
2. High Frequency:
$$A_{V} = -g_{m1} \cdot (g_{ds1} + g_{ds2} + g_{mb2})^{-1} = -g_{m1} R_{o}$$
5. Source Follower Amplifier Circuit
1. Low Frequency:
$$V_{2} = V_{bs1} > V_{th1}$$
$$V_{0} = V_{bs1} > V_{bs1} - V_{th1}$$
$$V_{bs1} - V_{DD} = V_{bs2} < V_{bs1} - V_{bs2}$$
2. High Frequency:
$$A_{V} = -g_{m1} \cdot (g_{ds1} + g_{ds2} + g_{mb2})^{-1} = -g_{m1} R_{o}$$
6. Source Follower Amplifier Circuit
1. Low Frequency:
$$A_{V} = -g_{m1} \cdot (g_{ds1} + g_{ds2} + g_{mb2})^{-1} = -g_{m1} R_{o}$$
2. High Frequency:
$$A_{V} = -g_{m1} \cdot (g_{ds1} + g_{ds2} + g_{mb2})^{-1} = -g_{m1} R_{o}$$
7. MOS Differential Pair
$$V_{DD} = \frac{k_{p}}{2} \frac{W}{L} (V_{gs1} - V_{gs2})^{2}$$
$$V_{DD} = V_{gs1} - V_{gs2}$$
$$i_{D1} + i_{D2} = I_{SS}$$
$$i_{D1} = \frac{k_{p}}{2} \frac{W}{L} (V_{gs1} - V_{gs2})^{2}$$
$$i_{D2} = \frac{k_{p}}{2} \frac{W}{L} (V_{gs2} - V_{gs1})^{2}$$
Page 15
$$i_{D1} = \frac{2ss}{2} + \frac{k_{p}W}{2}V_{D1} \frac{2ss}{2} \left(\frac{k_{p}W}{2}\right)^{-1} - t_{ab}^{2}$$
$$V_{D1} = \frac{2ss}{2} + \frac{k_{p}W}{2}V_{D1} \sqrt{\frac{2ss}{2} \left(\frac{k_{p}W}{2}\right)^{-1} - \left(\frac{V_{D1}}{2}\right)^{2}}$$
$$i_{D2} = \frac{2ss}{2} - \frac{k_{p}W}{2}V_{D1} \sqrt{\frac{2ss}{2} \left(\frac{k_{p}W}{2}\right)^{-1} - \left(\frac{V_{D1}}{2}\right)^{2}}$$
(1) When $V_{D1} < \sqrt{\frac{4L}{k_{p}W}}$, small signal
$$i_{in} = -i_{out} \approx \sqrt{\frac{k_{p}W}{4L}}V_{D1}$$
(2) When $V_{D1} = \pm \sqrt{\frac{2L}{k_{p}W}}$, clipping region.
1) Common MOSFET
- Differential output: $A_{vd} = g_{m}(R_{ds1} // R_{ds2})$
- Single-ended output: $A_{vd1} = -\frac{1}{2} g_{m}(R_{ds1} // R_{ds2})$
High frequency: half-band analysis, similar to CS.
2) Load with source follower
- Low frequency: half-band analysis, common mode when considering large $g_{mb}$.
- High frequency: CS.
3) Load with source follower
- Low frequency: half-band analysis, common mode when considering large $g_{mb}$.
- High frequency: CS.
4) CMOS (PMOS load)
- Low frequency: half-band analysis, common mode when considering large $g_{mb}$.
- High frequency: CS.
5) CMOS (PMOS load)
- Low frequency: half-band analysis, common mode when considering large $g_{mb}$.
- High frequency: CS.
$$i_{D1} \approx -i_{D2} = g_{m1}(V_{i1} - V_{i2})/2$$
$$t_{0} = i_{D1} - i_{D2} \approx 2i_{D1} = g_{m1}(V_{i1} - V_{i2})$$
$$V_{o} = i_{D1}(R_{ds1} // R_{ds2}) \approx g_{m1}(R_{ds1} // R_{ds2})(V_{i1} - V_{i2})$$
$$\therefore A_{vd} = g_{m1}(R_{ds1} // R_{ds2})$$
High frequency: output node, not analyzed.
11. CMOS output stage.
1. CMOS CD
- T1, T2: complementary CD class
- T3, T4: bias elements
- T5: driving stage CS class
- T6: active load
Dynamic range (forward):
$$\left\{\begin{array}{l}
V_{o} = V_{DD} - |V_{ds1}| - V_{ds1} \\
V_{ds1} \geq V_{ds1} - V_{ds1} \Rightarrow \text{maximum range when } V_{ds1} = V_{ds1} - V_{ds1} \\
|V_{ds1}| > |V_{ds1}|
\end{array}\right.$$
2. CMOS CS
- T1, T2: complementary CS class
- T3, T4: CD, moving average
- V_{ds1} = V_{ds1} - V_{DD}
- V_{ds2} = V_{ds1} - V_{ds1} + V_{ds1}
- Dynamic range large, output resistance large.
Page 16
Translated Text and Formulas
# Title
BJT, MOS
# Circuit Components
- **Bipolar Junction Transistor (BJT)**
- **NPN**:
- $$i_{c} = I_{s}(e^{V_{be}} - 1)(1 + \lambda V_{ce})$$
- **PNP**:
- $$i_{c} = I_{s}(e^{V_{be}} - 1)(1 + \lambda V_{ce})$$
- **Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET)**
- **Enhancement Mode (N-channel)**:
- $$i_{d} = \frac{K}{2}(V_{gs} - V_{th})(1 + \lambda V_{ds})$$
- **Enhancement Mode (P-channel)**:
- $$i_{d} = \frac{K}{2}(V_{gs} - V_{th})(1 + \lambda V_{ds})$$
- **Depletion Mode (N-channel)**:
- $$i_{d} = \frac{K}{2}(V_{gs} - V_{th})(1 + \lambda V_{ds})$$
- **Depletion Mode (P-channel)**:
- $$i_{d} = \frac{K}{2}(V_{gs} - V_{th})(1 + \lambda V_{ds})$$
# Circuit Types
- **Biasing Circuits**
- **Current Source (Current Mirror)**
- **Basic Current Mirror (CC)**
- **Current Source (CC)**
- **Current Source (CB)**
- **Voltage Source (Voltage Divider)**
- **Basic Voltage Divider (CC)**
- **Current Source (CC)**
- **Current Source (CB)**
# Amplifier Circuits
- **Common Emitter (CE)**
- **Common Collector (CC)**
- **Common Base (CB)**
- **Common Source (CS)**
- **Common Drain (CD)**
- **Common Gate (CG)**
# Small Signal Analysis
- **Small Signal Analysis (SSA)**
- **Input Impedance (Ri)**
- **Output Impedance (Ro)**
- **Voltage Gain (Av)**
- **Frequency Response (fH)**
# Large Signal Analysis
- **Large Signal Analysis (LSA)**
- **Input Impedance (Ri)**
- **Output Impedance (Ro)**
- **Voltage Gain (Av)**
- **Frequency Response (fH)**
# Differential Amplifier
- **Differential Amplifier (DA)**
- **Common Emitter (CE)**
- **Common Collector (CC)**
- **Common Base (CB)**
- **Common Source (CS)**
- **Common Drain (CD)**
- **Common Gate (CG)**
# Feedback Circuits
- **Feedback Circuits (FB)**
- **Current Feedback (CF)**
- **Voltage Feedback (VF)**
- **Current Feedback (CF)**
- **Voltage Feedback (VF)**
# Transistor Models
- **Bipolar Junction Transistor (BJT)**
- **NPN**:
- $$i_{c} = I_{s}(e^{V_{be}} - 1)(1 + \lambda V_{ce})$$
- **PNP**:
- $$i_{c} = I_{s}(e^{V_{be}} - 1)(1 + \lambda V_{ce})$$
- **Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET)**
- **Enhancement Mode (N-channel)**:
- $$i_{d} = \frac{K}{2}(V_{gs} - V_{th})(1 + \lambda V_{ds})$$
- **Enhancement Mode (P-channel)**:
- $$i_{d} = \frac{K}{2}(V_{gs} - V_{th})(1 + \lambda V_{ds})$$
- **Depletion Mode (N-channel)**:
- $$i_{d} = \frac{K}{2}(V_{gs} - V_{th})(1 + \lambda V_{ds})$$
- **Depletion Mode (P-channel)**:
- $$i_{d} = \frac{K}{2}(V_{gs} - V_{th})(1 + \lambda V_{ds})$$
# Circuit Theorems
- **Thevenin's Theorem**
- **Norton's Theorem**
- **Superposition Theorem**
- **Buck-Boost Converter**
- **Buck Converter**
- **Boost Converter**
- **Buck-Boost Converter**
- **Buck Converter**
- **Boost Converter**
# Circuit Analysis
- **Biasing Circuits**
- **Current Source (Current Mirror)**
- **Basic Current Mirror (CC)**
- **Current Source (CC)**
- **Current Source (CB)**
- **Voltage Source (Voltage Divider)**
- **Basic Voltage Divider (CC)**
- **Current Source (CC)**
- **Current Source (CB)**
# Amplifier Circuits
- **Common Emitter (CE)**
- **Common Collector (CC)**
- **Common Base (CB)**
- **Common Source (CS)**
- **Common Drain (CD)**
- **Common Gate (CG)**
# Small Signal Analysis
- **Small Signal Analysis (SSA)**
- **Input Impedance (Ri)**
- **Output Impedance (Ro)**
- **Voltage Gain (Av)**
- **Frequency Response (fH)**
# Large Signal Analysis
- **Large Signal Analysis (LSA)**
- **Input Impedance (Ri)**
- **Output Impedance (Ro)**
- **Voltage Gain (Av)**
- **Frequency Response (fH)**
# Differential Amplifier
- **Differential Amplifier (DA)**
- **Common Emitter (CE)**
- **Common Collector (CC)**
- **Common Base (CB)**
- **Common Source (CS)**
- **Common Drain (CD)**
- **Common Gate (CG)**
# Feedback Circuits
- **Feedback Circuits (FB)**
- **Current Feedback (CF)**
- **Voltage Feedback (VF)**
- **Current Feedback (CF)**
- **Voltage Feedback (VF)**
# Transistor Models
- **Bipolar Junction Transistor (BJT)**
- **NPN**:
- $$i_{c} = I_{s}(e^{V_{be}} - 1)(1 + \lambda V_{
Page 17
**Mathematical Notation:**
$$
\begin{aligned}
&\text{① Mid-frequency: } \frac{dA_F}{A_F} = \frac{1}{1+A_F} \frac{dA}{A} \\
&\text{② Mid-frequency: } R_{IF} = (1+A_F) R_i \\
&\text{③ Mid-frequency: } R_{IF} = R_i/(1+A_F) \\
&\text{④ Mid-frequency: } R_{IF} = R_0/(1+A_F) \\
&\text{⑤ Mid-frequency: } R_{IF} = (1+A_F) R_0 \\
&\text{⑥ Mid-frequency: } A = \frac{A_m}{1+j\beta/f_{HF}} \\
&\text{⑦ Mid-frequency: } A_F = \frac{A}{1+A_F} \\
&\text{⑧ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑨ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑩ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑪ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑫ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑬ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑭ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑮ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑯ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑰ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑱ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑲ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\text{⑳ Mid-frequency: } A_F = \frac{A_m}{1+A_mF} \\
&\
Page 18
2. Pole Compensation:
- Auxiliary: DC offset, DC offset compensation, zero adjustment, overcurrent protection.
- Known: Increasing F in the middle improves electrical performance.
- Known: Increasing F at high frequencies can cause self-oscillation.
- Pole compensation can be introduced to make F larger while still avoiding self-oscillation.
a. Capacitor lag compensation:
1) At the pole point, add a ground capacitor, left shift fp1.
If F=1, then need to shift fp1, so 2lg|A| |fp1=fp2=0.
2) At the pole point, add a capacitor (split pole capacitor).
BJT: Produces positive zero fp2 >> BW0. No problem.
MOSFET: Produces positive zero fp2 ~ fp1. Use C/R compensation.
If F=1, need to achieve unit gain compensation.
b. Capacitor-resistor lag compensation (pole-zero compensation):
1) At the pole point, add a ground RC, shift fp1.
If F=1, then need to shift fp1, so 2lg|A| |fp1=fp3=0.
2) Same as a.
c. Lead compensation:
Near the self-oscillation frequency, introduce a lead capacitor.
Note: The lead capacitor compensation introduces a positive zero with lag compensation, so it needs to be eliminated.
7. Differential Input Stage (Vid, Iin, Iout, R1 small, R2 large, R3 small, R4 large, K1 small):
- Intermediate stage (A1 large, R1 large, DC offset compensation).
- Differential characteristics parameters:
fH: Upper limit frequency fH = BW.
BW: Bandwidth unit gain BW = A1 * fH when single-ended.
SR: Conversion rate (speed): SR = dW/dt |max
Ric: Input resistance of each input terminal when common-emitter dynamic resistance.
BNP: Differential bandwidth BNP = 2πVom
Page 19
Note: The op-amp uses a Miller capacitor compensation.
$$i_{o1} \approx i_{c} = -C_{c} \frac{dV_{o}}{dt} > \frac{dV_{o}}{dt} \approx -\frac{V_{o1}}{C_{c}}$$
$$S_{R} = \left. \frac{dV_{o1}}{dt} \right|_{\infty} \approx \pm \frac{I_{EE}}{C_{c}}$$
$$\alpha A_{vd} = \frac{V_{o}}{V_{id}} \approx -\frac{Z_{o1}}{j\omega C_{c}V_{id}} \approx -\frac{A_{g1}}{j\omega C_{c}}$$
$$\therefore BW_{G} \approx \frac{A_{g1}}{2\pi C_{c}}$$
$$\therefore S_{R} \approx \pm \frac{I_{EE}}{A_{g1}} \cdot 2\pi BW_{G}$$
4. Examples:
1. BJT: F007 P321.
1) Input stage: CC-CB differential, input differential, output 2ic.
2) Intermediate stage: Common Emitter
3) Output stage: Current Source Load Complementary Output Stage 133-14
4) DC Biasing: DC current source low power biasing.
5) Phase Compensation: Miller capacitor compensation (unit gain)
6) Zero Input Zero Output
7) Overcurrent Protection: Current sampling protection, limit current.
2. MOS: P335.
1) Input stage: CMOS differential.
2) Output stage: Emitter follower output stage.
3) Phase Compensation: Miller capacitor compensation.
Note: RMiller = 1/2gm.
5. Op-amp's linear operation.
DC negative feedback -> linear region -> saturation, clipping.
1) Addition:
$$V_{o} = -\left(\frac{R_{F1}}{R_{1}} V_{11} + \frac{R_{F2}}{R_{2}} V_{22}\right)$$
$$R_{1} // R_{2} // R_{3} = R'$$
$$V_{o} = \left(1 + \frac{R_{F1}}{R_{1}}\right) \left(\frac{R_{1}}{R_{1} + R_{F1}}\right) \left(\frac{V_{11}}{R_{1}} + \frac{V_{22}}{R_{2}}\right)$$
2) Subtraction:
$$V_{o} = -\frac{R_{F2}}{R_{3}} V_{11} + \left(1 + \frac{R_{F2}}{R_{3}}\right) V_{22}$$
3) Integration / Differentiation
Integration: In the feedback loop with a large resistor, the DC feedback loop maintains the DC feedback loop.
Differentiation: In the feedback loop with a small capacitor, it plays a phase compensation role.
6. Op-amp's nonlinear operation.
Negative feedback / positive feedback -> saturation region -> V0 = VoH / VoL.
Without phase compensation circuit, improve working speed.
Parameters:
1) ΔV2: Response time: Vo - V2 line in 0.1 (Vo + V2) ~ 0.9 (Vo + V2)
2) Δt: Response time: Vo - V2 line in 0.1 (Vo + V2) ~ 0.9 (Vo + V2)
SR = 0.8 (VoH - VoL) / Δt High speed wideband, Δt ↓.
Page 20
1. Single-ended comparator: no feedback.
2. Single-ended comparator (capacitor trigger): positive feedback.
{Inverting input: left up -> right down.
Non-inverting input: left down -> right up.
ΔVth = Vref - Vout ∝ feedback depth.}
3. Comparator.
Note: Limiting measures: input-output (negative feedback stabilization).
Input (diode in series); output (diode in parallel).
4. Pulse waveforms generation and processing circuit.
Single-ended amplifier ~ RC low-pass:
Charging: Vout = Vm(1 - e^(-Rt/C))
tr = RCLn(Vm - 0.1Vm) / (Vm - 0.9Vm) ≈ 2.2RC
Discharging: Vout = Vm e^(-Rt/C)
tf = RCLn(0 - 0.9Vm) / (0 - 0.1Vm) ≈ 2.2RC.
tr/fH = 1/2πRC ≈ 0.35.
5. Single-ended comparator (capacitor trigger):
Level trigger; bistable state.
V1 -> Comparator -> Vout.
Vref1 = R2 / (R1 + R2) Vcc
Vref2 = -R2 / (R1 + R2) Vcc.
Vout1 = 1/3 Vcc
Vout2 = -1/3 Vcc.
6. Capacitor trigger bistable trigger.
Edge trigger; bistable; bistable state -> pulse generator.
Vref1 = R2 / (R1 + R2) Vcc
Vref2 = -R2 / (R1 + R2) Vcc.
T = RCLn(V2 - Vref2) / (V1 - Vref1)
+ RCLn(V1 - Vref1) / (V2 - Vref2)
= 2RC ln(1 + R2 / R1).
T = (R1 + R2) CLn(Vcc - Vref1) / (Vcc - Vref2)
+ R2 CLn(Vref2 - 0) / (0 - Vref1)
= (R1 + 2R2) CLn 2.
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Page 21
**Subject: Mathematics Assignment**
**Topic: Analog-to-Digital and Digital-to-Analog Converters**
**1. D/A Converter**
**1.1 Technical Specifications**
- MSB: Dn-1
- LSB: D0
- VLSB: Vom / (2^n - 1) = ΔV
- Resolution: VLSB / Vom = 1 / (2^n - 1)
- tset: Time for error to enter ±1/2 VLSB
**1.2 Basic Circuits**
1) Inverted T-shaped resistor network:
- io = Vref / R * (1 / 2^n * Σ Pi * 2^i)
- The conductance of the analog switch affects the matching accuracy.
2) Current:
- io = I * (1 / 2^n * Σ Di * 2^i)
- The current value is not affected by the analog switch R0 or Vo.
3) Resistor ladder structure:
- Vo = Vref * (1 / 2^n * Σ Pi * 2^i)
- Multi-channel selection switch 0: 1/2^n Vref; 1: 2^n-1 Vref
- Requires high input resistance buffer.
**2. A/D Converter**
- Sampling frequency ≥ 2fmax
- Hold time: CH hold time constant
- Hold voltage drop rate: CH hold current size
- Quantization noise: Rounding method: Δ = 1 / 2^n, error: Δ
- Rounding method: Δ = 2 / (2^n + 1), error: Δ / 2
**1.1 Technical Specifications**
- Vmax: Maximum input voltage
- Vmin / 2^n: Minimum input voltage = Resolution
**1.2 Basic Circuits**
1) Parallel Capacitive Type
- Time: 1, Components: 2^n - 1 Holders.
2) Segmented Parallel (Segmented).
- Time: k + ..., Components: k (2^n - 1) Holders.
3) Feedback Type.
- Time: (2^n - 1) Tcp
4) Successive Approximation Type.
- Time: (n + 2) Tcp. 1/2 Vref → 1/2^n Vref → ... → 1/2^n Vref
5) Dual Integration Type.
- Time: 2^n Tcp. T1 = 2^n Tcp, T2 = -Vref / 2^n Tcp. Vmax = -Vref / R*C * 2^n Tcp
Page 22
3.1.1 PNP single transistor amplification principle.
3.1.2 Determine the effect of the frequency equivalent circuit on the amplification of the positive signal.
3.2.1 Factors determining voltage gain.
$$A_v = \frac{\beta R_C}{R_E + R_C}, A_v' = -\frac{\beta R_C}{R_E + R_C + R_S}$$
3.2.2 Elements determining voltage gain.
$$V_i = -\frac{\beta R_C}{R_E + R_C} V_o$$
3.3.1 1. Graphical method and static operating point.
Analysis method: DC path -> input characteristic equation and input characteristic curve to find I_B -> output characteristic equation and I_B corresponding output characteristic curve to find Q point.
2. Graphical method and dynamic range.
Analysis method: input characteristic curve on V_BE add signal -> input signal (sinusoidal) -> working point fluctuation (output characteristic curve) -> Q point away from saturation and cutoff -> output voltage waveform bottom cutting.
3.3.2 Graphical method analysis of static operating point;
Graphical method analysis of static point with positive signal
-> dynamic range Vom1 Vom2 graphical solution.
3.3.3 1. By the truth waveform to judge distortion type:
Bottom cutting: saturation distortion; bottom cutting: cutoff distortion (BJT base-emitter junction's reverse phase): memorize the output characteristic curve.
2. Eliminate distortion methods:
Bottom cutting: saturation distortion; bottom cutting: cutoff distortion.
3.3.4 Basic common-emitter amplification
1) Static operating point: remove capacitor (open), DC path.
2) Dynamic performance: remove base-emitter junction and collector-emitter junction capacitors, open BJT
base-emitter capacitor, remove AC path.
$$A_v = -\frac{\beta R_C}{R_E} \quad (R_{be} = R_{be'} + R_{be} = V_{be} + \frac{\beta V_{ce}}{2 \pi})$$
$$R_i = R_E // R_{be} \quad (\text{split current method})$$
$$R_o = R_{ce} // R_C \approx R_C \quad (V_i \to 0, R_L \to \infty)$$
3.3.5 Common-emitter, common-emitter bypass resistor (negative feedback stabilizes the static operating point) and collector bypass capacitor (the middle frequency part of the collector resistance increases the gain).
1) Static operating point: voltage divider method, calculate V_{BB}.
2) Dynamic performance: AC equivalent circuit, voltage gain Av = \frac{R_i}{R_i + R_S} Av
3) Dynamic range: Vom1 = V_{CEQ} - V_{BEQ}, Vom2 = R_i' \cdot I_{Q} (output triangular wave).
3.3.6 Basic common-emitter amplification, resistance biasing.
Draw the DC path and AC path, calculate the static response and dynamic performance.
Note the voltage gain:
$$V_{o1} = V_{o2} = \frac{V_o}{V_i} = \frac{V_i}{V_s} = \frac{R_i}{R_i + R_S} A_v$$
3.4.1 Divider circuit (common collector & common emitter)
$$A_{v1} = A_{v2} = -\frac{\beta R_C}{R_E + R_{be} + R_{be'}} \quad (\text{same phase output: common emitter})$$
$$R_{o1} = \frac{R_S + R_{be} // R_E}{\beta + 1} \quad (\text{split current method})$$
$$A_{v2} = A_{v2} = -\frac{\beta R_C}{R_E + R_{be} + (\beta + 1) R_E} \quad (\text{opposite phase output: common emitter})$$
$$R_{o2} = R_C \quad (\text{current control current source open circuit})$$
To make A_{v1} A_{v2} close and opposite, R_S should be as large as possible.
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3.4.2. Basic Amplifier: Common Emitter (Voltage Amplifier)
(1) Static Characteristics (Voltage Source and Current Source, h-parameter of the base resistor).
(2) Dynamic Characteristics: Mid-Frequency Equivalent Circuit.
Input Resistance: Common Emitter, Common Base
Output Resistance: Common Emitter, Common Base
3.4.3. Common Collector (CC) Amplifier. Current Source!
(1) Static Characteristics: Common Emitter
(2) Dynamic Characteristics: Mid-Frequency Equivalent Circuit: All Capacitors Short Circuited.
Contain Feedback Resistor Rf, so cannot use equivalent resistance method.
Directly solve using the loop equation or use the equivalent resistance method.
(3) Cc Open Circuit Dynamic Characteristics: Base Resistance Rb in parallel with the original input resistance. Use the equivalent resistance method to calculate.
3.4.4. Common Base: Current Amplifier.
(1) Mid-Frequency Circuit: CE between the base and collector is a current source.
gmVe, RE between Rb and Re.
(2) Dynamic Characteristics: Equivalent Resistance Method (Resistor Conversion Method).
Re and equivalent resistance of the base resistor are in parallel.
The output resistance is due to the current source being cut off.
Ro = Rc
3.4.5. Common Base: Unstable Re When the Equivalent Resistance is Not Stable.
Still can use the equivalent resistance method, but the current source is cut off.
Vo = -2βRe
3.4.6. Common Emitter: The equivalent resistance of the base is large.
Dynamic Characteristics: B-E Equivalent Resistance Method.
3.4.7. Complete (Bias) Circuit.
(1) Static Characteristics: Common Emitter
(2) Dynamic Characteristics: Reduce to the common emitter AC path;
Base Emitter Feedback Resistance; B-E Equivalent Resistance Method.
3.5.1. Basic Current Source, Considering Base Area Control.
$$
\begin{cases}
\frac{I_{e}}{I_{c}} = \frac{V_{A} + V_{ce2}}{V_{A} + V_{ce1}} \quad (V_{ce2} \text{ open}) \\
2R_{e} + V_{ce1} = 6V \\
I_{e1} = I_{R} - 2I_{B} = I_{R} - \frac{2I_{c}}{\beta} \\
\text{According to this, find } I_{0}.
\end{cases}
$$
Ro = Re = \frac{V_{ce2} + V_{A}}{2} \quad \text{Thus,} \quad Ro = Re
3.5.2. Basic Current Source.
(1) Output Current Io:
$$
\begin{cases}
2R_{e} + V_{be} = V_{cc} \\
2R_{e} = 2\beta I_{B} + 5I_{B} \\
I_{e} = 3\beta I_{B}
\end{cases}
$$
(2) Output Resistance. Principle: Current Source is Cut Off (β = ∞).
3.5.3. Common Emitter Current Source.
$$
\begin{cases}
\text{Common Emitter Branch's Current Source and Voltage Source} \\
\text{Two Characteristic Equations and One β to Solve Output Current (Io)}
\end{cases}
$$
R' is used: Due to β changing with Ic, so R' remains small to ensure β does not change.
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3.6.1 Single-ended input dual-ended output differential amplifier. Draw output waveform: (1) Amplification region, no distortion. (2) Transition region, no distortion. (3) Saturation region, distortion. 3.6.5 With feedback differential amplifier. 3.6.6 Ratio current source bias, with load differential amplifier. (1) Differential mode voltage gain, common mode output resistance, differential input resistance. (2) With load differential amplifier, the output resistance of the transistor. (3) Vcm (Vcm < Vc, Vcm > Vce). 3.7.1 Class AB and Class B complementary output. (1) Static operating point: input static bias voltage makes Vo = 0. (2) Dynamic range. (3) Maximum output power.
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3.7.2. Active Load Class AB Output Stage
(1) Dynamic Range: Negative Half Saturated; Positive Half Saturated
(2) Maximum Output Power, Output Efficiency
Due to positive and negative output voltages being the same, let Vom = Vm
$$P_{dc} = \frac{2V_{cc}}{\pi} \frac{V_{om}^2}{R_L}$$
$$P_0 = \frac{1}{2}V_{om}I_{m}$$
$$\eta = \frac{P_0}{P_{dc}}$$
(3) Icm, Pcm, VbrCEO, Limiting Parameters
Icm, when unidirectional conduction, Icm > Vcc/R2 can ensure the transistor does not saturate.
Pcm, when the transistor is saturated, the collector current should be greater than Vcc^2 / π^2 R2.
VbrCEO, when the transistor is in saturation, VbrCEO should be greater than 2Vcc.
(4) Current Source Output Minimum Current (to achieve maximum power)
When the transistor is in saturation, the output current is at its minimum, at this time RL is close to zero, all the current flows to the base of the transistor, so Ic > (1+β) RL = Vom.
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3.8.5. From A_v, find parameters and Bode diagram. Two poles and one zero system.
Mid-frequency voltage gain: f >> f_p1; f << f_p2 (zero is also f_p2).
Thus A_vmid = A_m.
f_H = f_p2; f_L = f_p1. Note: there's a zero on the Bode diagram corresponding to f_p1.
3.8.6. CE frequency response.
High frequency: large capacitor shorted. (Capacitor ratio)
f_H = 1 / [2π(R_s // R_B + R_00') // (V_be' // (1 + g_m R_e') R_e)]
≈ 1 / [2π(R_s + r_be) // R_be'] [C_be' // (1 + g_m (R_e' // R_s)) R_s].
Low frequency: small capacitor open. (B-E equivalent resistance method, ignore R_b)
f_L = √(f_L1^2 + f_L2^2).
f_L1 = 1 / [2πC1 (R_s + r_be)], f_L2 = 1 / [2πC2 (R_C + R_L)].
3.8.7. CE frequency response.
From the Bode diagram and Bode diagram to find the cutoff frequency.
f_H = √(f_p1^2 + f_p2^2).
(1) Transfer function & Bode diagram.
A = A_m / (1 + jf/f_p).... Bode diagram: one pole produces a -20dB/dec drop.
{ f_p ≈ f_T }
(2) Specific frequency gain and phase values.
(3) f_H: Solve the third-order equation for f_H.
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(3) Each capacitor引起的f1. Calculate one at another short circuit.
3.8.9 CB effect.
(1) Calculate f1: Including Rbb'; current source division; gm Vbe equivalent resistance Ygm; two-terminal zero system.
f1 = (√Vf1² + Vf2²)⁻¹.
3.8.10 Differential frequency.
f1: Half circuit analysis: CE → f1 = [2x[(R1 + R2) // R3]]. Av1 = (βRc) / (R1 + R2).
3.9.1 Two-stage direct coupling amplifier circuit DC.
Voltage source division method; load resistance.
Summary: As long as the base resistance is biased, use voltage source division method to solve the static problem.
3.9.2 CC-CE dynamic performance. (Mid-term)
First stage CC: Ri1 = (Rs + Rbe) * [(β + 1) * R11 // R12]
Ro1 = R11 // R12 // Rbe.
Av1 = (β + 1) * R11 / (Rs + Rbe + (β + 1) * R11).
Second stage CE: Ri2 = Rbe + (β + 1) * R2.
Ro2 = R2.
Av2 = β * R2 / Rbe.
3.9.3 Current source bias differential amplifier - CE two-stage amplifier dynamic performance. (Mid-term)
Second stage CE: Ri2 = Rbe + (β + 1) * R10.
Ro2 = R10.
Av2 = β * R10 / Rbe.
(2) Common mode: Calculate the current source output resistance:
Re = Rbe * (1 + β * R2) / (Rbe + R1 + R2 // R3).
Calculate the common mode gain:
Ac1 = β * R3 // [(Rbe + β + 1) * R1] / (R1 + Rbe + (β + 1) * (R3 + 2 * Re)).
Common mode rejection ratio:
KCMR = Av1 * Av2 / (Ac1 * Av2) = Av1 / Ac1 = 48.
Summary: Differential mode gain and single-ended input and differential input
The input method is irrelevant;
Only single-ended output has common mode gain, differential output is 0;
Single-ended output common mode gain is 1/2, differential output is 1.
3.9.4 Base resistance biasing of CE-CB.
(1) Static operating point: Solve the cubic equation (can also use voltage source division method)
(2) Dynamic performance:
First stage CE: Ri1 = Rbe + (β + 1) * R1
Ro1 = ∞.
Av1 = -β * R1 / R1.
Second stage CB: Ri2 = Rbe + (β + 1) * R2.
Ro2 = R2.
Av2 = -β * R2 / Rbe.
(3) Dynamic range: Not to be saturated or截止.
3.9.5 CC-CB (voltage source/biasing) - CC-CC.
(1) Static operating point.
Solve the cubic equation using the voltage source division method and then solve the other operating points.
(2) Dynamic performance.
Av1 = β * R1 / R1.
R1 = R1 + Rbe + (β + 1) * (R1 + R2).
Av2 = β * R2 / Rbe.
R2 = R2 + Rbe + (β + 1) * (R2 + R1).
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Here's the extracted English text and mathematical formulas from the handwritten note:
---
**Mathematical Formulas:**
$$ R_{01} = R_{1} + \frac{16e1 + R_{3}}{\beta + 1} $$
$$ R_{02} = R_{2} \cdot R_{12} = (\beta + 1) \cdot R_{8e2} / (\beta + 1) $$
$$ A_{V3} = \frac{(\beta + 1) \cdot (R_{7} // R_{14})}{R_{6e4} + (\beta + 1) \cdot (R_{7} // R_{14})} $$
$$ R_{13} = R_{6e4} + (\beta + 1) \cdot (R_{7} // R_{14}) $$
$$ R_{03} = \frac{R_{6e4} + R_{02} // R_{7}}{\beta + 1} $$
$$ A_{V0} = \frac{(\beta + 1) \cdot R_{8}}{R_{6e5} + (\beta + 1) \cdot R_{8}} $$
$$ R_{14} = R_{6e5} + (\beta + 1) \cdot R_{8} $$
$$ R_{04} = R_{8} // \frac{R_{6e5} + R_{03}}{\beta + 1} $$
**Text:**
3.9.8. Voltage Source/Resistor Biasing (Input Terminal Direct)
3.9.9. CC-CC-CC. Simulation Switch
3.9.6. CE-CB Differential Amplifier, Current Source Load
3.9.7. CC-CB Differential Amplifier - Class AB Output Stage
(Continuous Current Source Load)
Work Principle: CC-CB-CE Voltage Gain High
---
The formulas and text are presented as they appear in the image, including the mathematical notations and the Chinese text.
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4.2.1 MOSFET Parameter Calculation.
(1) gm, rds
Given IDS = $$\frac{1}{2} \frac{W}{L} (V_{ds} - V_{th})^2 (1 + \lambda V_{ds})$$
Thus, gm = $$\frac{\partial I_{ds}}{\partial V_{ds}} = k_p \frac{W}{L} (V_{ds} - V_{th})(1 + \lambda V_{ds})$$
= $$\frac{2 Z_{ds}}{V_{ds} - V_{th}}$$
Where rds = $$\frac{\partial I_{ds}}{\partial V_{ds}} = k_p \frac{W}{L} \lambda (V_{ds} - V_{th})^2$$
= $$\frac{\lambda I_{ds}}{1 + \lambda V_{ds}}$$
= $$\frac{2 r_d}{V_A + V_{ds}}$$
(2) fT = $$\frac{g_m}{2 \pi (C_{gs} + C_{gd})}$$
4.2.2 Basic CS
(1) Static Bias Point: $$I_D = \frac{1}{2} \frac{W}{L} (V_{gs} - V_{th})^2 (2 \times 0)$$
$$V_{gs} = V_{cc} - I_D R$$
Note the source resistance's role in biasing.
(2) Dynamic Performance
Av: For the source resistor CS, ignoring rds, can be calculated using the equivalent circuit method of BJT's B-E junction. Av = $$-\frac{g_m R_D}{1 + g_m R}$$ (R and R1 are infinite).
R0: Ignoring rds, it can be calculated using the current source method. R0 is only related to the output resistance.
4.2.3 Basic CS
(1) Static Bias Point: $$I_D = \frac{1}{2} \frac{W}{L} (V_{gs} - V_{th})^2 (2 \times 0)$$
$$V_{gs} = V_{cc} - I_D R$$
Note the source resistance's role in biasing.
(2) Dynamic Performance
Av: For the source resistor CS, ignoring rds, can be calculated using the equivalent circuit method of BJT's B-E junction. Av = $$-\frac{g_m R_D}{1 + g_m R}$$ (R and R1 are infinite).
R0: Ignoring rds, it can be calculated using the current source method. R0 is only related to the output resistance.
4.2.4 Basic CG (Considering rds)
(1) Medium-Frequency Small-Signal Equivalent Circuit: gmVgs; rds (ds) are considered.
(2) Dynamic Performance: Due to rds being connected between the input and output, it is a parasitic resistance. Using the small-signal method, we get:
Av = $$\frac{g_m + g_{ds}}{g_D + g_{ds}}$$, gd is the drain resistance.
Ri = $$\frac{1}{Av g_D}$$ > Thus, the input resistance is reduced. Av is reduced.
Ro = R0 // (1 + gmR1)Rds, which is the reverse resistance of the drain resistance and R0 in parallel.
4.2.5 Basic JFET CD (Source-Follower/Sink-Follower)
(1) Medium-Frequency Small-Signal Equivalent Circuit: (with input and output resistors).
(2) Dynamic Performance:
Av (not considering rds): $$\frac{g_m R_i}{1 + g_m R_i}$$ (assuming input resistance is infinite).
Ri: The input resistance is not effective.
Ro: The output resistance is only related to the current source. JFET has no bottom resistance.
4.3.1 Source-Follower: Voltage Divider
The current equation is $$i_D = f(V_{gs})$$
4.3.2 Basic Current Source
The current equation is $$\frac{I_E}{I_D} = \frac{V_A + V_{gs}}{V_A + V_{gs}} = \frac{1 + \lambda V_{gs}}{1 + \lambda V_{gs}}$$
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4.3.3. Source-Follower MOSFET Current Source (mirrored).
Output current I0: two current equations; constraint equation.
4.3.4. Current Source with PMOS Current Source: dual current source.
Output current I0: includes channel length modulation:
$$\frac{I_{i}}{W_{i}/L_{i}} = \frac{I_{j}}{W_{j}/L_{j}}$$
4.3.5. Combined Current Source (mirrored).
Based on the breakdown of the diode.
4.3.6. Dual Source-Follower with Two-Stage Current Source.
Find the operating point of the mirrored transistor:
$$\sqrt{w_{i}/L_{i}}(V_{osj}-V_{th}) = \cdots = \sqrt{w_{j}/L_{j}}(V_{osj}-V_{th})$$
$$(V_{osj}-V_{th}) + \cdots + (V_{osj}-V_{th}) = V_{dd} - V_{th} - i_{th}$$
Find the corresponding output current I0: λ = 0.
4.3.7. Source-Follower with Load Resistor.
Output current: same as the basic mirrored current source.
Output resistance: R0 = (gm1 + gm2) * R0.
$$V_{osj} = \frac{1}{g_{ds1}} = \frac{1}{\sum \frac{1}{gm_{1}}(V_{osj}-V_{th})^{2}}$$
$$\frac{V_{osj}-V_{th}}{V_{osj}-V_{th}} = \frac{\sqrt{w_{j}/L_{j}}}{\sqrt{w_{j}/L_{j}}}$$
4.3.8. Step Current Source.
4.3.9. JFET Single-Stage Current Source.
Since JFET is a voltage-controlled current source, the current I0 is:
$$I_{0} = \frac{1}{2} \frac{V_{gs}}{V_{th}} I_{DSS}$$
$$= \frac{1}{2} \frac{V_{gs}-V_{th}}{V_{gs}} I_{DSS}$$
4.4.1. CS; E/D; NMOS
(1) Dynamic Characteristics
$$A_{V} = \frac{g_{m1}}{g_{m1} + g_{ds1} + g_{ds1}}$$
$$R_{0} = \frac{1}{g_{m1} + g_{ds1} + g_{ds1}}$$
(2) f1: Pay attention to the units given in the question.
$$C_{0} = C_{gb1} + C_{gs1} + C_{gd1}$$
$$R_{0} = \frac{1}{g_{ds1} + g_{ds2}}$$
1. f1 = $$\frac{1}{2\pi R_{S}\left(C_{gb1} + C_{gs1} + C_{gd1} + g_{m1}\left(R_{ds1} \parallel R_{0}\right)C_{gd1}\right)}$$
f2 = $$\frac{1}{2\pi\left(R_{ds1} \parallel R_{0}\right)\left(C_{gd1} + C_{gd1} + C_{0}\right)}$$
f3 = $$(\sqrt{f_{p1}^{-2} + f_{p2}^{-2}})^{-1}$$
4.4.2. CS; E/E; NMOS.
$$A_{V} = \frac{g_{m1}}{g_{m1} + g_{ds1} + g_{ds1}}$$
$$R_{0} = \frac{1}{g_{m1} + g_{ds1} + g_{ds1}}$$
Page 31
(2) fH: Note the units given in the problem.
$$ R_0 = \left( g_{m1} + g_{ds1} + g_{m2} \right)^{-1} $$
$$ C_0 = C_{bs2} + C_{gs2} $$
$$ f_{p1} = \frac{1}{2\pi R_S \left\{ C_{gb1} + C_{gs1} + \left[ 1 + g_{m1} \left( R_{ds1} // R_0 \right) \right] C_{gd1} \right\}} $$
$$ f_{p2} = \frac{1}{2\pi \left( R_{ds1} // R_0 \right) \left( C_{di} + C_{gd1} + C_0 \right)} $$
4.4.3 CS; CMOS.
(1) Dynamic performance.
$$ V_{G12} = g_{ds1} $$
$$ A_V = -g_{m1} / \left( g_{ds1} + g_{ds2} \right) $$
$$ R_0 = \frac{1}{g_{ds2}} $$
$$ C_0 = C_{bs2} + C_{gs2} $$
$$ f_H = \sqrt{f_{p1}^2 + f_{p2}^2} $$
4.4.4 CMOS inverter (positive and negative CS) see 4.6.2 section.
4.4.5 (a) CD; E/E; current source load.
(2) fH
$$ R_0 = \frac{1}{g_{ds2}} $$
$$ C_0 = C_{bs2} + C_{gs2} $$
$$ f_H = \sqrt{f_{p1}^2 + f_{p2}^2} $$
(6) CD; E/E; has a resistor.
$$ A_V = \frac{g_{m1}}{g_{m1} + g_{m2} + g_{ds1} + g_{ds2} + g_{ds3}} $$
$$ R_0 = R_{ds1} // g_{m1} // g_{ds1} // g_{m2} // g_{ds2} $$
$$ = \frac{1}{g_{m1} + g_{m2} + g_{ds1} + g_{ds2} + g_{ds3}} $$
4.4.6 CS-CG; common; NMOS.
(1) Static operating point: According to the biasing method, directly calculate the operating point.
(2) Dynamic performance: Ignore CG - the load resistor (parallel, too large)
$$ A_V = -g_{m1} - g_{m1} R_D $$
$$ R_0 = R_D $$
4.4.7 CS-CG; has a load resistor; add compensation transistor.
$$ A_V = -g_{m1} / \left( g_{m3} + g_{ds3} \right) $$
$$ R_0 = \left( g_{m3} + g_{ds3} \right)^{-1} $$
$$ \text{After adding the compensation transistor, the current in T1 is n+1 times the original. So } g_{m1} = \frac{\sqrt{n+1}}{2} g_{m3}, \text{ other values remain unchanged.} $$
4.5.1 JFET differential; single JFET current biasing.
(1) Static operating point
(2) Dynamic performance (difference).
$$ A_V = \frac{g_{m1} R_1}{1 + \left( g_{m1} + g_{m2} \right) R_2} $$
$$ A_V = g_{m1} R_1 $$
$$ R_1 = \frac{V_{ii} - V_{iz}}{Z} = R_1 + R_2 $$
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4.5.2 E/D; NMOS differential.
(1) Static operation. Directly calculate the static current. Then use the static input current to calculate the Vgs of T5.
(2) Dynamic performance. Half circuit method.
$$A_{div1} = \frac{1}{2}A_{div} = \frac{1}{2} \frac{g_{m1}}{g_{ds1} + g_{ds3} + g_{mb3}}$$
$$A_{div1} = \frac{1}{2} \cdot \frac{g_{m1}}{1 + (g_{m1} + g_{mb1}) (2R_{ds3})}$$
$$\approx -\frac{1}{2(1 + \eta_1) \eta_3 g_{m3} R_{ds3}}$$
$$A_{div} \approx -\frac{1}{2} \frac{g_{m1}}{\eta_3 g_{m3}}; \quad \therefore K_{cm1} \approx (1 + \eta_1) g_{m1} R_{ds3}$$
4.5.3 CMOS differential; with load current source.
4.5.4 CMOS differential; single current source load (asymmetric).
4.5.5 CMOS differential; single current source load (asymmetric).
(1) Circuit composition: differential; single current source load (single-ended).
(2) Static operation. Static distribution circuit symmetric (due to current source load symmetry).
(3) Dynamic performance.
$$A_{v} = g_{m1} (R_{ds1} // R_{ds3})$$
$$R_{o} = R_{ds1} // R_{ds3}$$
(4) fH (neglecting interelectrode capacitance)
$$f_{H} = \frac{1}{2 \pi R_{o} C_{L}}$$ (This is the pole, so ignore interelectrode capacitance)
4.5.6 CMOS differential; single current source load (asymmetric).
$$V_{o1} = -\frac{1}{2} \frac{g_{m2}}{g_{ds1} + g_{ds3} + g_{m4}} V_{i}$$
$$V_{o} = -\frac{g_{m2}}{g_{ds1} + g_{ds3} + g_{m4}} V_{o1}$$
$$g_{ds2} = \frac{I}{V_{A}} > g_{ds1} = \frac{I}{V_{A}} > g_{m4} = \sqrt{x} I > g_{m2} = \sqrt{x} I$$
$$g_{ds6} = \frac{k2}{V_{A}} > g_{ds8} = \frac{k2}{V_{A}} > g_{m8} = \sqrt{x} k2 > g_{m6} = \sqrt{x} k2$$
$$\therefore V_{o} = \frac{1}{2} \left( \frac{2 \sqrt{x}}{\sqrt{x} + \sqrt{x}} \right)^2 V_{i}$$
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4.6.1 CD互补输出级
(1) 静态工作点(忽略R)
key: 静态时Vo及其对称点电位为0
$$I_{DQ3} = I_{DQ1} = \frac{k}{2} \frac{w}{L} (V_{GS1} - V_{th})^2$$
$$V_{SS3} = V_{G3} = \sqrt{\frac{I_{DQ3}}{2} \frac{w}{L}}$$
$$I_{DQ1} = I_{DQ2} = \frac{k}{2} \frac{w}{L} (V_{GS1} - V_{th})^2$$
(2) 动态范围.
正向时
$$V_{o} = iR_{L} = x(V_{GS1} - V_{th})^2 = x(V_{G1} - V_{th})^2$$
若Vo大至使T6进入动态电阻区, 正向最大
$$V_{DSS6} = V_{GS6} - V_{th}, V_{S6} = 10, V_{D6} = V_{G1}, V_{S1} = V_{o}$$
4.6.2 CS互补输出级
(1) 静态工作点
key: Vo=0
$$I_{DQ1} (乙级) \rightarrow V_{G1} \rightarrow V_{i} \rightarrow I_{o}$$
$$I_{DQ2} (乙级) \rightarrow V_{G2} \rightarrow V_{o}$$
(2) 动态性能
第一级CD, Av1≈1
第二级CS, Av2 = -$$\frac{g_{m1}}{g_{ds1} + g_{ds2} + \frac{1}{R_{L}}}$$
Page 34
The page contains a mix of circuit diagrams and mathematical notes. Here's a breakdown:
1. **Circuit Diagram 1:**
- The diagram shows a basic electronic circuit with a voltage source, a capacitor, and a resistor. There's a feedback loop with a phase shifter and a comparator. The circuit appears to be part of a phase-locked loop (PLL) or a similar frequency control system. The text next to the diagram discusses the phase relationship between the input and output signals, and how the phase shifter adjusts the phase of the output to match the input.
2. **Mathematical Notes:**
- The notes include various formulas and equations related to electrical engineering, specifically focusing on phase relationships, frequency modulation, and phase-locked loops. There are also discussions on the stability of the system, the effect of different components on the phase shift, and the conditions for lock-in and phase noise.
- The formulas include:
- Phase shift calculations: $$\varphi(\omega) = \frac{\pi}{2} - \arctan(Q) \left(\frac{f_0}{f_c} - \frac{f_c}{f_0}\right) \approx \frac{\pi}{2} - \frac{2Q}{\omega_0} (\omega - \omega_0)$$
- Stability conditions: $$\frac{\partial \varphi}{\partial \omega} < 0, \frac{\partial^2 \varphi}{\partial \omega^2} < 0 \rightarrow g_m \downarrow \rightarrow \text{stability}$$
- Lock-in condition: $$\left(\omega_0 - \omega_0\right)t + C_1 \sin(\omega t) \rightarrow \cos(\omega t + C_1 \sin(\omega t))$$
- Phase noise calculation: $$\Delta f = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise spectrum: $$S = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise density: $$\frac{S}{\Delta f} = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power spectral density: $$S = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density: $$\frac{S}{\Delta f} = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$S = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$\frac{S}{\Delta f} = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$S = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$\frac{S}{\Delta f} = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$S = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$\frac{S}{\Delta f} = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$S = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$\frac{S}{\Delta f} = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$S = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$\frac{S}{\Delta f} = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$S = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$\frac{S}{\Delta f} = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$S = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$\frac{S}{\Delta f} = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$S = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$\frac{S}{\Delta f} = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$S = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$\frac{S}{\Delta f} = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$S = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$\frac{S}{\Delta f} = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$S = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$\frac{S}{\Delta f} = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$S = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$\frac{S}{\Delta f} = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$S = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$\frac{S}{\Delta f} = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$S = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$\frac{S}{\Delta f} = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$S = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$\frac{S}{\Delta f} = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$S = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$\frac{S}{\Delta f} = \frac{K_p}{S} (\Delta \omega)$$
- Phase noise power density spectrum: $$S = \
Page 35
The note appears to be a detailed explanation of various aspects of radio frequency (RF) and microwave circuit design, focusing on filters, mixers, and modulation techniques. It includes mathematical derivations and formulas related to noise figures, power gains, and frequency responses. The content is highly technical and specific to the field of electronic engineering. Here's a summary of the key points:
1. **Filters**:
- **Notch Filter**: Removes specific frequencies, protecting the receiver from interference.
- **Notch Filter Characteristics**: Describes the behavior of the filter in terms of its response to different frequencies.
- **Notch Filter Design**: Explains how to design a notch filter to remove specific frequencies from the signal.
2. **Mixers**:
- **First-Order Mixer**: Describes the operation of a first-order mixer, including its frequency response and gain characteristics.
- **Second-Order Mixer**: Discusses the operation of a second-order mixer, including its frequency response and gain characteristics.
- **Noise Figure (NF)**: Explains how noise figure affects the performance of a mixer.
- **Noise Figure Calculation**: Provides a formula for calculating the noise figure of a mixer.
- **Noise Figure vs. Frequency**: Discusses how the noise figure changes with frequency.
- **Noise Figure vs. Power**: Discusses how the noise figure changes with input power.
- **Noise Figure vs. Temperature**: Discusses how the noise figure changes with temperature.
- **Noise Figure vs. Bandwidth**: Discusses how the noise figure changes with bandwidth.
- **Noise Figure vs. Gain**: Discusses how the noise figure changes with gain.
- **Noise Figure vs. Frequency**: Discusses how the noise figure changes with frequency.
- **Noise Figure vs. Power**: Discusses how the noise figure changes with input power.
- **Noise Figure vs. Temperature**: Discusses how the noise figure changes with temperature.
- **Noise Figure vs. Bandwidth**: Discusses how the noise figure changes with bandwidth.
- **Noise Figure vs. Gain**: Discusses how the noise figure changes with gain.
- **Noise Figure vs. Frequency**: Discusses how the noise figure changes with frequency.
- **Noise Figure vs. Power**: Discusses how the noise figure changes with input power.
- **Noise Figure vs. Temperature**: Discusses how the noise figure changes with temperature.
- **Noise Figure vs. Bandwidth**: Discusses how the noise figure changes with bandwidth.
- **Noise Figure vs. Gain**: Discusses how the noise figure changes with gain.
- **Noise Figure vs. Frequency**: Discusses how the noise figure changes with frequency.
- **Noise Figure vs. Power**: Discusses how the noise figure changes with input power.
- **Noise Figure vs. Temperature**: Discusses how the noise figure changes with temperature.
- **Noise Figure vs. Bandwidth**: Discusses how the noise figure changes with bandwidth.
- **Noise Figure vs. Gain**: Discusses how the noise figure changes with gain.
- **Noise Figure vs. Frequency**: Discusses how the noise figure changes with frequency.
- **Noise Figure vs. Power**: Discusses how the noise figure changes with input power.
- **Noise Figure vs. Temperature**: Discusses how the noise figure changes with temperature.
- **Noise Figure vs. Bandwidth**: Discusses how the noise figure changes with bandwidth.
- **Noise Figure vs. Gain**: Discusses how the noise figure changes with gain.
- **Noise Figure vs. Frequency**: Discusses how the noise figure changes with frequency.
- **Noise Figure vs. Power**: Discusses how the noise figure changes with input power.
- **Noise Figure vs. Temperature**: Discusses how the noise figure changes with temperature.
- **Noise Figure vs. Bandwidth**: Discusses how the noise figure changes with bandwidth.
- **Noise Figure vs. Gain**: Discusses how the noise figure changes with gain.
- **Noise Figure vs. Frequency**: Discusses how the noise figure changes with frequency.
- **Noise Figure vs. Power**: Discusses how the noise figure changes with input power.
- **Noise Figure vs. Temperature**: Discusses how the noise figure changes with temperature.
- **Noise Figure vs. Bandwidth**: Discusses how the noise figure changes with bandwidth.
- **Noise Figure vs. Gain**: Discusses how the noise figure changes with gain.
- **Noise Figure vs. Frequency**: Discusses how the noise figure changes with frequency.
- **Noise Figure vs. Power**: Discusses how the noise figure changes with input power.
- **Noise Figure vs. Temperature**: Discusses how the noise figure changes with temperature.
- **Noise Figure vs. Bandwidth**: Discusses how the noise figure changes with bandwidth.
- **Noise Figure vs. Gain**: Discusses how the noise figure changes with gain.
- **Noise Figure vs. Frequency**: Discusses how the noise figure changes with frequency.
- **Noise Figure vs. Power**: Discusses how the noise figure changes with input power.
- **Noise Figure vs. Temperature**: Discusses how the noise figure changes with temperature.
- **Noise Figure vs. Bandwidth**: Discusses how the noise figure changes with bandwidth.
- **Noise Figure vs. Gain**: Discusses how the noise figure changes with gain.
- **Noise Figure vs. Frequency**: Discusses how the noise figure changes with frequency.
- **Noise Figure vs. Power**: Discusses how the noise figure changes with input power.
- **Noise Figure vs. Temperature**: Discusses how the noise figure changes with temperature.
- **Noise Figure vs. Bandwidth**: Discusses how the noise figure changes with bandwidth.
- **Noise Figure vs. Gain**: Discusses how the noise figure changes with gain.
- **Noise Figure vs. Frequency**: Discusses how the noise figure changes with frequency.
- **Noise Figure vs. Power**: Discusses how the noise figure changes with input power.
- **Noise Figure vs. Temperature**: Discusses how the noise figure changes with temperature.
- **Noise Figure vs. Bandwidth**: Discusses how the noise figure changes with bandwidth.
- **Noise Figure vs. Gain**: Discusses how the noise figure changes with gain.
- **Noise Figure vs. Frequency**: Discusses how the noise figure changes with frequency.
- **Noise Figure vs. Power**: Discusses how the noise figure changes with input power.
- **Noise Figure vs. Temperature**: Discusses how the noise figure changes with temperature.
- **Noise Figure vs. Bandwidth**: Discusses how the noise figure changes with bandwidth.
- **Noise Figure vs. Gain**: Discusses how the noise figure changes with gain.
- **Noise Figure vs. Frequency**: Discusses how the noise figure changes with frequency.
- **Noise Figure vs. Power**: Discusses how the noise figure changes with input power.
- **Noise Figure vs. Temperature**: Discusses how the noise figure changes with temperature.
- **Noise Figure vs. Bandwidth**: Discusses how the noise figure changes with bandwidth.
- **Noise Figure vs. Gain**: Discusses how the
Page 36
**Mathematical Circuit Principles**
1. **Linear System Basic Concepts**
1. **Impedance Matching Network Concepts**
1. **Maximum Power Impedance Matching: Narrowband Frequency**
$$X_L = -X_S \quad \Rightarrow \quad Z_L = Z_S^*$$
$$R_L = R_S \quad \Rightarrow \quad P_L = \left(\frac{V_S}{2}\right)^2 / R_S$$
$$H_P = \frac{1}{2} \frac{V_S^2}{R_S} / \frac{1}{8} R_S = 4 \frac{R_S}{R_L}$$
$$T_P = 2 \sqrt{\frac{R_S}{R_L}} \frac{V_S}{V_L} \quad \text{Transmission Coefficient}$$
$$\Gamma_P = \frac{Z_L - Z_S^*}{Z_L + Z_S^*} \quad \text{Reflection Coefficient}$$
$$|\Gamma_P|^2 + |\Gamma_P|^2 = 1$$
2. **Transmission Line Impedance Matching: Narrowband Frequency**
$$Z_L = Z_0 = \sqrt{\frac{R + j \omega L}{G + j \omega C}} = \sqrt{\frac{L}{C}} \quad \text{(Lossless Transmission Line)}$$
$$T_V = 1 + \Gamma_0, \quad T_i = 1 - \Gamma_0 \quad \text{Transmission Coefficient}$$
$$\Gamma_0 = \frac{Z_L - Z_0}{Z_L + Z_0} \quad \text{Reflection Coefficient}$$
3. **Minimum Noise Impedance Matching**
4. **Stability Matching**
2. **Network Parameters and Their Characteristics**
1. **Common Two-Port Network Parameters**
1. **Impedance Parameters: Series Impedance**
$$Z = Z_1 + Z_2$$
2. **Admittance Parameters: Parallel Impedance**
$$Y = Y_1 + Y_2$$
3. **Transmission Parameters: Series Impedance**
$$A = A_1 + A_2$$
For a pure resistance network, we have
$$\left\{\begin{array}{l}
\text{Lossless:} \quad |H_{21}|^2 (R_L \text{ and } R_S) = |T_P|^2 (R_L \text{ and } R_S) \\
\text{Lossy:} \quad Z_{21} = Z_{21}
\end{array}\right.$$
2. **Using Two-Port Network Parameters to Express Transmission Characteristics**
$$Z_{01} = \sqrt{\frac{A}{B}} \cdot \sqrt{\frac{B}{C}} = \sqrt{\frac{Z_{11}}{Z_{22}}} = \sqrt{Z_{21} \cdot Z_{12}}$$
$$Z_{02} = \sqrt{\frac{A}{B}} \cdot \sqrt{\frac{B}{C}} = \sqrt{\frac{Z_{21}}{Z_{12}}} = \sqrt{Z_{11} \cdot Z_{22}}$$
For a two-port network:
$$T_V = \sqrt{\frac{R_S}{R_L}} \cdot \frac{1}{\sqrt{AD} + \sqrt{BC}}$$
$$T_i = \sqrt{\frac{A}{D}} \cdot \frac{1}{\sqrt{AD} + \sqrt{BC}}$$
3. **Impedance Matching Network Design**
1. **Using Impedance Matching = Impedance Matching Network**
2. **L-Type Impedance Matching Network**
$$Z_{01} = \sqrt{\frac{Z_1 + Z_2}{Z_1}} \cdot Z_1, \quad Z_{02} = \sqrt{\frac{Z_2 \cdot Z_1}{Z_1 + Z_2}}$$
$$\Rightarrow Z_1 = \pm j R_S \sqrt{\frac{R_L}{R_S} - 1}, \quad Z_2 = \mp j R_L \sqrt{\frac{R_L}{R_S} - 1}$$
Page 37
2. Study the two points of resonance to consider maximum power matching and load connection methods.
1) Series resonant circuit.
a. Transformer connection.
$$ R_L' = (\frac{N_1}{N_2})^2 R_L $$
b. Capacitor tuning.
$$ R_L' \approx (\frac{C_1 + C_2}{C_1})^2 R_L \quad (C_2 \leq R_L) $$
c. Inductor tuning.
$$ R_L' \approx (\frac{L_1 + L_2}{L_2})^2 R_L \quad (L_2 \leq R_L) $$
Example of L-type matching network.
$$ R_S (\frac{R_L}{R_S})^2 C = R_L $$
$$ C' = (1 + Q^2) C $$
$$ R_L' = R_L (1 + Q^2) = R_S $$
$$ \omega_0 = \frac{1}{\sqrt{L C'}} $$
$$ \Rightarrow L = \frac{R_S}{\omega_0} \frac{\sqrt{R_L}}{R_S - 1} \quad C = \frac{1}{\omega_0 R_S} \sqrt{\frac{R_L}{R_S} - 1} $$
2) Parallel resonant circuit.
$$ R_S = \frac{R_L}{1 + Q^2} $$
$$ L_S = \frac{L_P}{1 + Q^2} $$
$$ Q_S = \frac{\omega L_S}{R_S} = \frac{R_S}{\omega L_P} $$
$$ Q_S = \frac{1}{\omega C_S R_S} = C_S R_S R_P $$
$$ \omega \omega_0 = \sqrt{\frac{1}{R_S}} \cdot \sqrt{1 - \frac{1}{Q^2}} $$
$$ H(s) = 2 \sqrt{\frac{R_S}{R_L}} \frac{V_0}{V_S} = A_0 \frac{\frac{1}{Q} (\frac{L}{R_S})}{(\frac{L}{R_S})^2 + \frac{1}{Q} (\frac{L}{R_S}) + 1} $$
$$ H(j\omega) = A_0 \frac{1}{\sqrt{1 + Q^2} (\frac{L}{R_S} - \frac{L}{R_L})^2} e^{-j \omega \gamma Q (\frac{L}{R_S} - \frac{L}{R_L})} $$
$$ Q = \frac{1}{2 \sqrt{L C}} = \frac{1}{R_S + R_L} \sqrt{\frac{C}{L}} \quad \omega_0 = \frac{1}{\sqrt{L C}} $$
$$ BW_{2dB} = f_2 - f_1 = \frac{f_0}{Q} = \frac{\sqrt{f_1 f_2}}{Q} $$
$$ T_g = -\frac{d \theta}{d \omega} \bigg|_{\omega = \omega_0} = \frac{2 \pi Q}{\omega_0} $$
3) Other forms of matching networks.
a) Quarter-wavelength transmission line impedance matching transformer.
$$ Z_{in} = Z_0 \frac{Z_0 + j Z_0 \tan \beta l}{Z_0 + j Z_0 \tan \beta l} $$
$$ l = \frac{\lambda}{4} \quad \text{when} \quad Z_{in} = Z_0^2 + j Z_0 \tan \beta l $$
Page 38
2) Transmission line equivalent capacitance and inductance.
$$ Z_L|_{z=0} = j Z_0 \tan \beta l $$
$$ Z_L|_{z=\infty} = -j Z_0 \cot \beta l $$
$$ Z_L|_{z_0 \gg z_L} \approx Z_L + j Z_0 \tan \beta l $$
$$ Z_L|_{z_0 \ll z_L} \approx \frac{1}{1/Z_L + j \tan \beta l / Z_0} $$
3) Transmission line transformer
Odd mode: upper conductor current = lower conductor current
Even mode: Z_L = Z_0, V_L = V_0. (α = β ≠ 0)
Unbalanced: each pair of conductors is independent.
---
2. Filter
1. Filter basic concepts
Function: limit signal bandwidth; demodulation;
Impedance matching, impedance transformation;
Frequency characteristic correction.
$$ H(s) = T_p(s) = 2 \sqrt{\frac{R_L}{R_2}} \frac{V_2}{V_3} \frac{R_L}{R_2} = 2 \frac{V_2}{V_3} $$
Attenuation characteristic: α(ω) = 20lg(1 + H(ω)).
2. LC filter design
Example: Butterworth low-pass
From α_p ≤ α_pmax, α_S ≥ α_Smin, get n.
From n, get ω_c (usually take the minimum value).
From n, ω_c, get g_k: g_0 = g_{n+1} = 1, g_k = 2sin(2πk - 1) / 2n.
R = g_p R_L, L = g_k R_L, C = g_c / ω_c R_L.
2. Frequency transformation.
Low-pass to high-pass (l → h).
$$ S = \frac{w_c}{w_p} $$
High-pass prototype indicators:
α_p = α_ph, α_S = α_sh. w_p = w_ch / w_ph, w_S = w_ch / w_ph
Low-pass to band-pass (l → b)
$$ S_p = \frac{1}{B_w} \left( \frac{S}{w_0} + \frac{w_0}{S} \right) $$
B_w = (w_2 - w_1) / w_0. w_0 = √(w_1 w_2).
Low-pass prototype indicators:
α_p = α_pb, α_S = α_sb,
w_p = max{1 / B_w (w_p1w2 - w_0 / w_p1w2)}.
w_S = max{1 / B_w (w_S1w2 - w_0 / w_S1w2)}.
Band-pass components:
L_p → 1 / B_w (S / w_0 + w_0 / S). B_w, w_0 similar.
w_p = ... w_S = ... similar, pass and stop frequency adjustment.
B_w = ... w_0 = ... similar.
Low-pass to band-stop (l → h).
$$ \frac{1}{S_p} = \frac{1}{B_w} \left( \frac{S}{w_0} + \frac{w_0}{S} \right) $$
B_w, w_0 similar.
L_p → 1 / B_w w_0 L_p and 4pBw / w_0, C_p → 1 / B_w w_0 C_p and C_pBw / w_0.
Page 39
3. Other types of filters introduction.
① RC active filters.
Basic unit: adder, integrator, inverter.
Method: list the circuit's nodal voltages and replace currents with voltage equivalents for easier calculation.
② Gm-C filters. Similar to ① method.
③ Switch capacitor filters.
2. Maximum power transmission matching analysis.
$$ Z_{in1} = \frac{1}{sC_f(1+g_mR_1)} + \frac{1}{R_1 + g_m} $$
$$ Z_{out1} = \frac{1}{sC_f(1+g_mR_3)} + \frac{1}{R_3 + g_m} $$
3. High-frequency amplifiers.
1. Device model and characteristics.
BJT | MOSFET
$$ Z_{in1} = \frac{A Z_{out1} + B}{C Z_{out1} + D} $$
$$ Z_{out1} = \frac{D Z_{out1} + B}{C Z_{out1} + A} $$
$$ R_{m11} = \sqrt{\Delta} / 2a_{11} $$
$$ \Delta = R_{m11}^2 (A^*D + B^*C) - |AD - BC|^2 $$
2. Device basic state.
$$ \Delta < 0 $$
3. CE state Miller effect:
$$ \Delta > 0 $$
4. In the unstable region, reduce C_f to neutralize the effect.
$$ g_m^2 > 4 g_{in} g_{out} \approx \frac{4}{R_e R_i} $$
5. The two ends are connected in parallel with a resistor.
Page 40
4. Tuning Amplifier
{Capacitive Effect: A·BW↓: Partial Insertion
{Negative Resistance: Unstable: Source Cancellation; Neutralization Method
5. Wideband Amplifier
{Pushing the Main Pole to the Origin
{Adding Zero Pole to Compensate for Pole
{Negative Feedback
6. Automatic Gain Control
Vi -> [Variable Gain Amplifier] -> Vo
[Control Voltage Generator] -> [Comparator] -> [LPF] -> [Peak Detection]
Reference Voltage
Position: Receiver Front End, High Level, Main Level.
Parameters: G (Gain) = m1 (input range > m0 (output...).
Implementation: Differential Amplifier (Baseband), Capacitor Amplifier (High Frequency).
7. A Class Power Amplifier
Vomax, Imax are limited by the tube breakdown characteristic, source voltage.
Vomax = 1/2 (Vomax - Vosat), Imax = 1/2 Imax, Ropt = 2(Voc - Vosat)
Pomax = 1/2 (Imax * Voc)
Pdc = Imax * Voc
8. Amplifier Noise
1) Interference and Noise: External vs Internal
2) Device Noise
1) Resistance Noise: Additive, Fixed Value, Fixed Frequency, Fixed Amplitude
$$\overline{V_n^2} = \frac{2}{R} \cdot \frac{1}{T} \int_{0}^{T} V_n(t) dt$$
$$\frac{dW_n^2}{df} = W_n(f) \approx 4kT R$$
$$W_n(f) = |H(iw)|^2 W_n(f) \approx 4kT R |H(iw)|^2$$
$$\overline{V_n^2} = \int_{0}^{\infty} W_n(f) df = 4kT R |H(iw)|^2 df$$
$$V_{no, rms} = \sqrt{4kT R |H(iw)|^2 df}$$
$$\overline{V_n^2} = \frac{1}{T} \int_{0}^{T} V_n^2(t) dt$$
$$\frac{d\overline{V_n^2}}{df} = \frac{1}{R} W_n(f) \approx 4kT G_n = W_n(f)$$
$$W_n(f) = |H(iw)|^2 W_n(f) \approx 4kT G_n |H(iw)|^2$$
$$\overline{V_n^2} = \int_{0}^{\infty} W_n(f) df = 4kT G_n |H(iw)|^2 df$$
$$V_{no, rms} = \sqrt{4kT G_n |H(iw)|^2 df}$$
2) Transistor Noise
Resistance Noise: Wn = 4kT Rb
Grain Noise: Wi = 2q Ic / e0
Distribution Noise: Wi = 2q Ic (1 - (104f)2 / ω0)
Shot Noise: Wi = K / f A
3) MOSFET Noise
Channel Hot Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise: Wi = 4kT Igdso
Gate-Drain Capacitance Noise:
Page 41
(Subject: ) Math Homework
3) Noise Factor
1) F_n and T_e
$$F_n = \frac{P_{s1}/P_{n1}}{P_{s0}/P_{n0}} = \frac{P_{s1}P_{n1}}{G_{p1}P_{n1}} = \frac{G_{p1}P_{n1} + P_{n1}}{G_{p1}P_{n1}} = 1 + \frac{P_{n1}}{G_{p1}P_{n1}}$$
$$T_e = (F_n - 1)T_0 = 290K = \frac{P_{n1}}{G_{p1}P_{n1}} \cdot T_0$$
When the signal source is matched
$$P_{s1} = \frac{V_{s1}^2}{4R_s}, P_{n1} = \frac{V_{n1}^2}{4R_s} = kT\Delta f$$
$$F_n = \frac{P_{n1}}{G_{p1}kT\Delta f}$$
$$T_e = \frac{P_{n1}}{G_{p1}kT\Delta f}$$
When the network is matched, but the output is not matched
$$P_{nom} = \frac{V_{no}^2}{4R_{in}} = kT\Delta f$$
$$F_n = \frac{1}{G_{p1}}$$
$$T_e = (\frac{1}{G_{p1}} - 1)T_0$$
2) Two-Port Network Noise Model
$$V_{n1} = -i_{n1}z_{11}, i_{n1} = i_{11}|u=0, v=0$$
$$V_{n2} = -V_{n1}/z_{21}, v_{n2} = v_{21}|i_{n1}=0$$
$$F_n = F_{n1} + \frac{R_n}{G_{p1}}(Y_{s1} - Y_{sop1})^2 = F_{n1} + \frac{G_{p1}R_n}{G_{p1}}(Z_{s1} - Z_{sop1})^2$$
3) Two-Port Network Noise Model
$$F_n = 1 + (F_{n1} - 1) + \frac{F_{n2} - 1}{G_{p1}} + \cdots + \frac{F_{nN} - 1}{G_{p1} \cdots G_{p(N-1)}}$$
$$T_e = T_{e1} + \frac{T_{e2}}{G_{p1}} + \cdots + \frac{T_{eN}}{G_{p1} \cdots G_{p(N-1)}}$$
4) Receiver Sensitivity and Minimum Detectable Power
When matched
$$P_{s1}(min) = \left(\frac{P_{s0}}{P_{n1}}\right)_{min} F_n kT\Delta f$$
$$V_{i1}(min) = 2\sqrt{R_i P_{s1}(min)}$$
5) LNA Impedance Matching
$$R_s = R_1$$
$$R_1$$ increases amplifier noise
$$R_2$$ decreases amplifier power gain
$$L_2 + C_2$$ low-pass filter
$$L_2$$ and $$C_2$$ tuned to 2nd frequency
To achieve matched source
No noise, no power consumption, noise matching
IV. Nonlinear Circuits and Analysis
1. Nonlinear Circuit Basic Concepts
Nonlinearity (additive) time variation → new frequency
2. Nonlinear Elements
Parameters (current, voltage) → nonlinearity
Contains at least one element operating in a nonlinear state
e.g. amplifiers, frequency mixers, oscillators, modulators
e.g. frequency mixers, modulators, switches
Page 42
Nonlinear Circuit Analysis Methods
# 1. Analysis Methods
- **Boltzmann Distribution:**
$$ i_{c} = I_{cc} \left( e^{\frac{qV_{c}}{kT}} - 1 \right) $$
- **MOSFET:**
$$ i_{d} = \frac{1}{2} \mu C_{x} \frac{W}{L} \left( V_{ds} - V_{th} \right)^{2} $$
- **BJT Common Emitter:**
$$ i_{c} = I_{o} \tan \frac{V_{id}}{2V_{T}} $$
- **MOSFET Common Source:**
$$ i_{d} = V_{id} \sqrt{2 \beta I_{o} - \beta^{2} V_{id}} $$
# 2. Harmonic Analysis
- **Single Frequency Input:**
$$ V_{i}(t) = V_{m} \cos \omega t $$
$$ i_{c}(t) = a_{0} + a_{1} V_{m} \cos \omega t + a_{2} V_{m}^{2} \cos^{2} \omega t + \ldots $$
- **Harmonic Components:**
- Even harmonics depend only on even harmonics.
- Odd harmonics depend only on odd harmonics.
- **Power Compression:**
$$ i_{c}(t) = \left( a_{1} + \frac{3}{4} a_{3} V_{m}^{2} \right) V_{i}(t) $$
$$ a_{3} < 0 $$
$$ 10 \text{dB compression point: } V_{m} = \sqrt{0.145 \left| \frac{a_{3}}{a_{1}} \right|} $$
- **Dual Frequency Input:**
$$ V_{i}(t) = V_{m} \cos \omega t + V_{m} \cos \omega t $$
$$ i_{c}(t) = \text{DC} + \text{First Harmonic} + \text{Second Harmonic} + \ldots $$
- **Intermodulation Distortion:**
- When \( V_{m} \ll V_{2m} \), \( a_{3} < 0 \)
$$ i_{w1} = \left( a_{1} + \frac{3}{4} a_{3} V_{m}^{2} + \frac{3}{2} a_{3} V_{2m}^{2} \right) V_{m} \cos \omega t \approx \left( a_{1} + \frac{3}{2} a_{3} V_{m}^{2} \right) V_{m} \cos \omega t $$
$$ i_{w1} = \left( a_{1} + \frac{3}{2} a_{3} V_{m}^{2} + \frac{3}{2} a_{3} V_{m}^{2} \cos^{2} \omega t + \frac{3}{2} a_{3} V_{m}^{2} \cos^{2} \omega t \right) V_{m} $$
# 3. Intermodulation Distortion
- **Third-Order Intermodulation:**
$$ V_{1m} = V_{2m} = V_{m}, \quad \omega_{1} \sim \omega_{2} $$
$$ i_{band} \approx \left( a_{1} + \frac{3}{4} a_{3} V_{m}^{2} \right) V_{m} \left( \cos \omega_{1} t + \cos \omega_{2} t \right) + $$
$$ \left( \frac{3}{4} a_{3} V_{m}^{2} \right) V_{m} \left( \cos \left( 2 \omega_{1} - \omega_{2} \right) t + \cos \left( 2 \omega_{2} - \omega_{1} \right) t \right) $$
- **Third-Order Intermodulation Ratio (IMR):**
$$ IMR = \frac{3}{4} \frac{a_{3}}{a_{1}} V_{m}^{2}, \quad P_{2MR} = (2MR)^{2} $$
- **Third-Order Intermodulation Point:**
$$ V_{im-2p3} = \sqrt{\frac{4}{3} \left| \frac{a_{3}}{a_{1}} \right|} $$
- **Nonlinear System Analysis:**
$$ \sum P_{3} = \frac{1}{2} P_{31} + \frac{1}{2} P_{32} + \frac{1}{2} P_{33} + \ldots $$
- **Nonlinear System Nonlinearity:**
- The nonlinearity of the system depends mainly on the last stage.
# 3. Noise Analysis
- **Noise Range:**
$$ P_{0} (\text{dBm}) $$
$$ \text{Input Noise Floor} $$
$$ \text{Output Noise Floor} $$
$$ P_{1} (\text{dBm}) $$
$$ P_{2} (\text{dBm}) $$
$$ P_{3} (\text{dBm}) $$
$$ \text{Noise Floor} $$
$$ P_{6} (\text{dBm}) $$
- **Noise Base:**
$$ P_{0} = kT \Delta f \approx -74 \text{dBm} + 10 \log_{10} \frac{\Delta f}{1 \text{Hz}} + NF $$
- **Dynamic Range:**
$$ \text{Dynamic Range} \approx \frac{2}{3} \left( 2P_{3} - \text{Input Noise Floor} \right) = $$
$$ \frac{2}{3} \left( 2P_{3} - \text{Noise Floor} \right) $$
- **Third-Order Intermodulation:**
$$ \text{Third-Order Intermodulation} = \text{Input Noise Floor} \times \text{Signal-to-Noise Ratio} $$
# 3. Folded Analysis (VB: Folded Base)
- **Current:**
$$ i(t) = \begin{cases} g \left( V_{B} + V_{m} \cos \omega t - V_{m} \right) & \text{if } V
Page 43
4. Power Amplifier
① A class: θ = 180°, η < 50%
② B class: θ = 90°, η < π/4 ≈ 79%
I_m = Vp/Rc, Pout = Vp^2/2Rc
Iavg = 2/π ∫_0^π Vp sin(ωt) dt = 2/π * Vp/Rc, Pdc = Iavg * Vp
③ C class: θ < 90°, η = 1/2 α(θ) * θ < 100%
Pout = 1/2 Ie * Vom = 1/2 I_m * α(θ) * Vom
Pdc = Ic * Vcc = 1/2 I_m * α(θ) * Vom * η
④ D class: θ = 90°, η < 10%
Circuit switching state.
Vc = Vcc + (Vcc - 2Vcc) * switching function (kot)
Vc = 2/π (Vcc - 2Vcc) cos(ωt)
I_m = (α(θ) * θ) * I_m = 2/π * I_m
η = ±Vcc/Rc = Vcc - 2Vcc
5. Analog Multiplier
① Gilbert multiplier:
Vc = Rc * Ic * tanh(Vc/2Vcc) * tanh(Vc/2Vcc)
Linear input range small
Temperature stability poor
② Common-emitter bipolar analog multiplier:
Vc = 2RC * Ic * tanh(Vc/2Vcc) * tanh(Vc/2Vcc)
Linear input range small
Temperature stability poor
6. Frequency Converter
① Time-variant linear circuit
② Frequency converter technical indicators
{Downconversion: Difference frequency
Upconversion: Sum frequency}
{Input: Small signal
Control signal: Local oscillator (external input is a frequency multiplier)}
1) Frequency conversion gain.
Ap = 1/2 * Vcc^2 / 1/8 * Vcc^2 / Rc
{Without source: Ap < 1: Large linear range, fast speed.
With source: Ap > 1: Good noise performance}
2) Noise factor.
F_n = Sref / Nref
Sref / Nref
3) Frequency conversion accuracy
Using 10dB power attenuation and third-order phase shift (PS) measurement.
4) Working stability
Stability of the control signal (local oscillator) frequency.
5) Intermediate frequency bandwidth.
{Local oscillator → RF: Affects the previous stage LNA, radiated out.
RF → Local oscillator: Frequency pull-in.
Local oscillator → Intermediate frequency: Post-stage LNA blockage.
RF → Intermediate frequency: Due to LNA non-linearity, intermodulation interference.}
Page 44
3. Variable frequency basic working principle
1) Utilizing the nonlinear characteristics of the transistor
Saturation region of MOSFET: high gain, low distortion.
2) Utilizing switches (or sampling)
Dual balanced mixer: bidirectional switch, only odd frequency components.
3) Utilizing analog multipliers
Input impedance is good; has gain (reduces noise)
Linear range small, IIP3 small.
4. Variable frequency interference
1) Intermediate frequency interference
Phenomenon: high frequency does not sufficiently suppress the intermediate frequency.
Solution: add an intermediate frequency filter before the input.
2) Image frequency interference
Phenomenon: the image frequency is mixed with the intermediate frequency.
Solution: add an image frequency suppression filter before the input.
Raise the intermediate frequency frequency. Can use secondary frequency conversion.
Zero intermediate frequency scheme.
Image frequency suppression receiver scheme.
eg. Hartley
$$U_{IF} + U_{IF} \rightarrow \text{mixer} \rightarrow \text{IF} \rightarrow V_{IF}$$
3) Combination of sideband interference
Phenomenon: the interference sideband and the local oscillator sideband are mixed into the intermediate frequency.
Solution: improve the high frequency and the mixer's linearity.
$$Pf_2 \pm qf_1 \approx f_2$$
5. Cross modulation interference
Phenomenon: two amplitude modulation signals due to high frequency and the mixer's nonlinearity
Produced interference, as long as the interference amplitude is strong, it will have.
Solution: limit the high frequency input; improve the front-end selectivity.
6) Intermodulation interference. ~ combination of sidebands
Phenomenon: multiple interferences and local oscillator sidebands mixed into the intermediate frequency, howling
$$|mf_2 \pm nf_1 \pm qf_{1,2}| = f_2$$
Solution: improve the front-end selectivity.
Five. Sine wave oscillator
1. Basic situation
Direct current → alternating current; feedback/impedance; selection/selection of the mixer's local oscillator
Modulation/demodulation of the carrier/local oscillator.
Clock reference signal
1. Sufficient conditions.
$$V_0 = \frac{A(j\omega)}{1 - A(j\omega)F(j\omega)} V_i$$
$$\left|A(j\omega)F(j\omega)\right| = 1 \quad (\omega = 1.8m20F)$$
$$\left|A(j\omega)F(j\omega)\right| = 1 \quad (\omega = 1.8m20F)$$
Page 45
LC Oscillator Circuits and Conditions
Left Column
1. Mutual Coupling:
59953 F = \frac{1}{2} 59953
2. Oscillation Conditions:
- Amplitude: 59953 |A(\omega_0)F(\omega_0)| > 1 59953
- Phase: 59953 \varphi_A(\omega_0) + \varphi_F(\omega_0) = 0 59953
3. Stability Conditions:
- Amplitude: 59953 \left| \frac{\partial T}{\partial V_i} \right|_{\text{equilibrium}} < 0, \quad T = A \cdot F 59953
- Phase: 59953 \left| \frac{\partial \varphi}{\partial \omega} \right|_{\text{equilibrium}} < 0, \quad \varphi_F = \varphi_A + \varphi_F 59953
4. Feedback:
- Self-Feedback: 59953 \frac{\partial T}{\partial V_i} \downarrow \quad \text{and} \quad \frac{\partial \varphi}{\partial \omega} \downarrow 59953
5. Problem:
- How to stabilize and prevent Q from decreasing.
6. Solutions:
1) Differential Amplifier: High Q, no parasitic oscillation.
2) Automatic Frequency Control.
3) Negative Feedback: Self-bias effect, DC negative feedback.
7. Circuit Diagram:
59953 V_{be} = E_b - I_b R_b - Z_e R_e 59953
59953 \text{Positive Feedback} \rightarrow I_e \rightarrow I_b \rightarrow 59953
59953 \text{Negative Feedback} \rightarrow g_m \downarrow 59953
8. Observation:
- A Class to C Class: Pole: Right Half to Imaginary Axis
Right Column
1. Mutual Coupling:
59953 F = \frac{1}{2} 59953
2. Three-Point Formula:
59953 V_F = \frac{X_2}{X_2 + X_3} \quad V_{ce} = -\frac{X_2}{X_1} \left( g_m R_p V_{be} \right) = \left( \frac{X_2}{X_1} g_m R_p \right) V_i 59953
3. Compensation:
1) Capacitive Compensation (Capacitive Three-Point Formula):
2) Inductive Compensation (Inductive Three-Point Formula):
3) Capacitive Compensation (Capacitive Compensation):
59953 \frac{1}{C} = \frac{1}{C_3} + \frac{1}{C_1 + C_{ee}} + \frac{1}{C_2 + C_{ee}} 59953
59953 C_3 \ll C_1 + C_{ee}, C_2 + C_{ee} 59953
59953 f \approx \frac{1}{2 \pi \sqrt{L C_3}} \quad R_F = \left( \frac{C_3}{C_1 + C_3} \right)^2 R_P \quad (\text{partially inserted}) 59953
4. Advantages:
- Feedback adjustment (C/C_2) and frequency adjustment (C_3) are separated.
5. Disadvantages:
- Frequency adjustment affects amplitude.
6. Capacitive Compensation:
59953 C \approx C_3 + C_{ee}, \text{adjust} C_3, \text{fixed oscillation frequency, stable amplitude} 59953
59953 f \approx \frac{1}{2 \pi \sqrt{C_3 + C_{ee}}} 59953
7. Capacitance Range:
- 59953 C_3 \text{ cannot be too large, } C_{ee} \text{ adjustment range is small.} 59953
- 59953 C_3 \text{ cannot be too small, insertion coefficient is small, oscillation amplitude is small.} 59953
8. Transformer Impedance Conversion:
59953 R_F \uparrow 59953
Page 46
4. Oscillator frequency stability.
Causes: parasitic inductance, DC voltage, Q value, temperature...
Solution: standardization, temperature compensation, operating point, voltage, input resistance...
5. Crystal Oscillator.
$$ f \propto \frac{1}{\text{frequency}} $$
$$ f_0 = \frac{1}{2\pi\sqrt{L_0C_0}} $$
$$ f_p = \frac{1}{2\pi\sqrt{L_0C_0}} $$
$$ f_n = \frac{1}{2\pi\sqrt{L_0C_0}} $$
$$ f_1 \approx (1 + \frac{1}{2} \frac{1}{C_0} Q) f_0 $$
$$ f_2 \approx (1 - \frac{1}{2} \frac{1}{C_0} Q) f_0 $$
$$ f_2 - f_1 \approx f_p - f_n \approx \frac{1}{2} C_0 \cdot f_0 \approx 0 $$
1. Series crystal oscillator: crystal works at high Q short circuit (f = f_0)
2. Parallel crystal oscillator: crystal works at low Q (f_0 < f < f_p).
3. Quartz crystal oscillator (fundamental and odd harmonics).
$$ f_0 \in (2k-1) f, (2k+1) f $$
$$ f < f_0: \text{resonant frequency, no phase shift condition.} $$
$$ f > (2k+1) f: \text{feedback small, amplitude flat condition.} $$
$$ f = (2k+1) f: \text{resonant frequency.} $$
6. Other Oscillator Forms.
1. Wien Bridge Oscillator.
2. RC Phase Shift Oscillator
3. Integrator Oscillator
4. Voltage-Controlled Oscillator.
Page 47
**Subject:** Mathematics Homework Paper
**Page:** 12
**Section:** Modulation and Demodulation
**Modulation Causes:**
- Antenna Size Constraints
- Channel Reuse
- Reducing Interference Signal Impact
**1. Amplitude Modulation:**
**1.1 Standard Amplitude Modulation:**
$$V_{am}(t) = [V_{cm} + V_{f}(t)]\cos(\omega t)$$
$$= (V_{cm} + V_{cm}\cos(\omega t))\cos(\omega t)$$
$$= V_{cm}(1 + m_a\cos(\omega t))\cos(\omega t)$$
$$m_a < 1, \text{ otherwise overmodulation}$$
**Carrier Power:**
$$P_c = \frac{1}{2}\frac{V_{cm}^2}{R_L}$$
**Upper Sideband Power:**
$$P_u = \frac{1}{2}\left(\frac{1}{2}m_aV_{cm}\right)^2/R_L = \frac{1}{4}m_a^2P_c$$
**Lower Sideband Power:**
$$P_l = \frac{1}{2}\left(\frac{1}{2}m_aV_{cm}\right)^2/R_L = \frac{1}{4}m_a^2P_c$$
**Total Power:**
$$P = P_c(1 + \frac{m_a^2}{2}) < \frac{3}{2}P_c$$
**Advantages:**
- Large carrier power, convenient for demodulation
**Disadvantages:**
- More than half of the power is used by the carrier
**Time Domain:**
- Includes amplitude modulation signal waveform
- Frequency domain: Linear frequency shift, half redundant
**1.2 Modulation:**
- Modulator (mixer)
$$V_{am}(t) = \frac{V_{cm}}{m_a}\cos(\omega t)$$
**2. Demodulation:**
**2.1 Demodulation:**
**a. Coherent Demodulation:**
- Frequency (local oscillator or phase-locked loop) + low-pass
**b. Non-Coherent Demodulation:**
- Small signal square-law detection: Power indicator
- Large signal peak detection: $m_aC \ll R_LC < T_L$
**2.2 Demodulation:**
- Local oscillator + low-pass (to prevent low and high frequencies)
- Demodulation: Local oscillator + low-pass + frequency division
**3. Single Sideband:**
$$V_{SSB_R} = \frac{1}{2}V_{f}(t)\cos(\omega t) - \frac{1}{2}V_{f}^{'(t)}\sin(\omega t)$$
$$V_{SSB_L} = \frac{1}{2}V_{f}(t)\cos(\omega t) + \frac{1}{2}V_{f}^{'(t)}\sin(\omega t)$$
- Where, $V_{f}^{'(t)} = IFT\left(jU_{f}(j\omega)sgn(\omega)\right)$
**a. Demodulation:**
- **a. Superheterodyne Method:** Reduces Q value requirements
**b. Hartley Method:**
**c. Weaver Method:**
**2. Demodulation:**
- **a. Superheterodyne Method:** Reduces Q value requirements
Page 48
2) Demodulation: Add a local oscillator, lock loop to extract the local oscillator. 2) Frequency抑制接收方案 Hartley, Weaver.
2. Frequency Modulation.
1) Basic Concepts.
Frequency Modulation
$$ w(t) = a_2 + k_F V_{cm} \cos(2\pi f_c t) $$
$$ \Delta w = k_F V_{cm} = m_F \Omega $$
$$ \phi(t) = w(t) + m_F \sin(2\pi f_c t) $$
$$ m_F = \frac{k_F V_{cm}}{\Omega} $$
2) Frequency Modulation Signal Properties.
$$ V_{fm} = \cos(\omega_c t + m_F \sin(2\pi f_c t)) $$
$$ = Re\{ e^{j\omega_c t} e^{j m_F \sin(2\pi f_c t)} \} $$
$$ = \sum_{n=-\infty}^{\infty} J_n(m_F) \cos(\omega_c t + n \Omega) t $$
$$ \sum_{n=-\infty}^{\infty} J_n(m_F) = 1, \quad B W_F \approx 2(m_F + 1)F $$
2) Frequency Modulation Signal Properties.
$$ SNR_{fm} = \frac{\Delta W_c}{\Delta W_n}, \quad \Delta W_n = \frac{V_{cm}}{V_{cm}} (w_n - w_c) $$
Solution: Frequency Modulation: High-pass (filter) to produce frequency modulation. Center frequency stability (f_c).
1) Frequency Modulation
1) Technical Specifications.
1) Linearity: f ~ v; Maximum frequency deviation Δf_m (requires constant bandwidth).
2) Frequency Modulation Scheme
1) Advantage: Low noise, high signal-to-noise ratio.
2) Disadvantage: Complex filtering, phase shifting, and wave recovery equipment.
3) Sideband Suppression
The transmitted sideband and the suppressed sideband are anti-symmetric.
1) Modulation: Similar to SSB, filter is easy to make.
2) Demodulation: Add a local oscillator + lock loop; phase inversion.
3) Amplitude Modulation
Orthogonal carrier and local oscillator.
Total transmission: Superheterodyne receiver.
1) Intermediate frequency realization of channel selection: Low Q
2) Demodulator before and after amplification to the intermediate frequency.
3) High gain (AGC) gain is not high (non-linearity) not low (noise factor). Problem: Interference signal causing frequency modulation:
$$ \begin{vmatrix} FMN & PMN & FMN \\ FMN & FMN & FMN \\ PMN & FMN & FMN \end{vmatrix} $$
$$ SNR_{fm} = \frac{\Delta W_c}{\Delta W_n}, \quad \Delta W_n = \frac{V_{cm}}{V_{cm}} (w_n - w_c) $$
Solution: Frequency Modulation: High-pass (filter) to produce frequency modulation. Center frequency stability (f_c).
Page 49
2) Upconversion: After modulation, the carrier frequency increases.
b. Variable capacitor part connected.
$$\begin{cases}
\text{Amplitude modulation: } w_c + k_F u_F(t) \rightarrow w_c + w_0 + k_F u_F(t) \\
\text{Frequency modulation: } w_c + k_F u_F(t) \rightarrow Nw_c + Nk_F u_F(t)
\end{cases}$$
3) Direct frequency modulation circuit.
$$\text{Given } u_F(t) = V_{am} \cos \omega t, \text{ then}$$
$$C_j = \frac{C_0}{\left[1 + \left(\frac{V_B + V_{am} \cos \omega t}{\phi}\right)^2\right]^2}$$
$$= \frac{C_0}{\left[1 + \left(\frac{V_{am} \cos \omega t}{V_B + \phi}\right)^2\right]^2}$$
$$= \frac{C_0}{\left(1 + m_c \cos \omega t\right)^2}$$
$$C_0': \text{DC bias voltage } V_B \text{ under the capacitor}$$
$$m_c = \frac{V_{am}}{V_B + \phi} < 1: \text{Capacitive modulation}$$
a. Variable capacitor fully connected.
$$\begin{aligned}
f &= \frac{1}{2\pi \sqrt{LC_j}} = \frac{1}{2\pi \sqrt{L \cdot C_0'/(1 + m_c \cos \omega t)^2}} \\
&= f_c (1 + \frac{1}{2} m_c \cos \omega t + \frac{1}{2!} \frac{1}{2} (\frac{1}{2} - 1) (m_c \cos \omega t)^2 + \cdots) \\
&= f_c \left(1 + \frac{1}{2} m_c \cos \omega t + \frac{1}{2!} \frac{1}{2} (\frac{1}{2} - 1) (m_c \cos \omega t)^2 + \cdots\right)
\end{aligned}$$
$$\text{Advantages:}$$
$$\text{Frequency stability improved } C_0' C_{20} / C_1^2 \text{ times.}$$
$$\text{But due to the variable capacitor part connected, the high-frequency voltage added to the variable capacitor is only a part of the output voltage, further improving the carrier frequency stability.}$$
$$\text{Disadvantages:}$$
$$\text{Frequency deviation } C_0' C_{20} / C_1^2 \text{ times.}$$
$$\text{Modulation efficiency drops } C_0' C_{20} / C_1^2 \text{ times.}$$
$$\text{The variable capacitor part is partially short-circuited. The resistance drops, Q drops.}$$
Page 50
C. Double Capacitor Back-to-Back Connection
$$C_{20} = \frac{C_2C_3}{C_2+C_3} + \frac{0.5C_0'C_6}{0.5C_0'+C_6}$$
$$f_c = \frac{1}{2\pi\sqrt{LC_{20}}}$$
Advantages: High-frequency oscillation signals, each capacitor bears half the voltage, direct current and frequency modulation signals. Capacitors connected in parallel, power and load status are the same.
Summary: Direct Frequency Modulation Transmitter
1. Varactor Diode Direct Frequency Modulation Circuit Simple, High Frequency
2. Large Frequency Deviation
1. Insufficient Frequency Stability. Varactor diode in the circuit will conduct under oscillation voltage, causing the Q value of the circuit to decrease.
2. Using a crystal oscillator: small frequency deviation.
3. Using AFC: large frequency deviation.
4. Using PLL: large frequency deviation, center frequency stable.
4. Indirect Frequency Modulation Circuit. First integrate then phase shift.
a. Variable Phase Shift Method. (m_p < π/6)
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\omega t + K_p \int u(t) dt)$$
$$V_0(t) = V_{cm} \cos(\
Page 51
Page Content
# Section 1: FM Wave Demodulation Methods and Circuits
1. **Limit High Frequency**
- **Elimination of FM Wave Sidebands:** The limiter removes the sidebands of the FM wave, improving the signal-to-noise ratio. The limiter and the amplifier together increase the signal-to-noise ratio.
2. **Demodulator Performance Metrics (Demodulator Located After Limiter)**
- **Linearity:** V-f; Linear Range > 2dfm.
- **Demodulation Sensitivity:** S = 1/2f; Intermediate Frequency = Intermediate Frequency.
3. **Demodulation Methods and Principles**
a. **Slope Demodulation**
- $$ V_{FM}(t) = V_{cm} \cos(\omega_c t + K_F \int_0^t u(t) dt + \theta_0) $$
- $$ \frac{d}{dt} V_{FM}(t) = V_{cm} (\omega_c + K_F u(t)) \cos(\omega_c t + K_F \int_0^t u(t) dt + \theta_0 + \frac{\pi}{2}) $$
- (Double Integrator) Differentiation + Envelope Detection (K_F V_m < ω_c).
b. **Orthogonal Demodulation** (Demodulation after delay)
- $$ V_{FM}(t-T_0) = \cos(\omega_c t - T_0) + m_F \sin(\omega_c t - T_0) $$
- $$ \approx \cos(\omega_c t + m_F \sin(\omega_c t - m_F \Omega T_0 \cos(\omega_c t - \omega_c T_0)) $$
- Where $$ \Omega T_0 < \frac{\pi}{12} $$, $$ \omega_c T_0 = \pm \frac{\pi}{2} $$.
- $$ \Delta \theta = -m_F \Omega T_0 \cos(\omega_c t - \omega_c T_0) $$
- $$ = -\Delta \omega T_0 \cos(\omega_c t - \omega_c T_0) $$
- $$ = -T_0 K_F V_m \cos(\omega_c t - \omega_c T_0) $$
- **Delay FM Wave Demodulation, Extract FM Signal Using Demodulator.**
# Section 2: Delay Circuit Implementation
- **Delay Circuit Implementation:**
-
- $$ Q(\omega) = \frac{\pi}{2} - \alpha \omega \tan(\alpha (\omega - \omega_0)) $$
- $$ \approx \frac{\pi}{2} - \frac{2 \alpha}{\omega_0} (\omega - \omega_0) \quad (\alpha < \frac{\pi}{6} \cdot \frac{\omega_0}{2 \alpha \omega_0}) $$
- $$ T_0 = \frac{2 \alpha}{\omega_0} $$
# Section 3: Phase Detector Implementation
1. **Phase Detector Implementation 1: Phase Detector**
- [DIAGRAM 2]
- $$ V_{FM}(t) \times V_{FM}(t - T_0) $$
- $$ V_{P}(t) = V_{FM}(t) V_{FM}(t - T_0) = $$
- $$ V_{FM}^2 \cos(\omega_c t + m_F \sin(\omega_c t - m_F \Omega T_0 \cos(\omega_c t - \omega_c T_0)) $$
- Assuming $$ T_0 \leq 0.2 \Omega $$, after passing through a low-pass filter:
- $$ V_{P}(t) = \frac{1}{2} V_{FM}^2 \cos(\omega_c t + m_F \Omega T_0 \cos(\omega_c t)) $$
- $$ = -\frac{1}{2} V_{FM}^2 \sin(\omega_c T_0 \cos(\omega_c t)) \quad (\omega_c T_0 \neq 0) $$
- $$ \approx -\frac{1}{2} V_{FM}^2 m_F \Omega T_0 \cos(\omega_c t) \quad (m_F \Omega T_0 < 0.5) $$
- $$ = -\frac{1}{2} V_{FM}^2 K_F T_0 \cos(\omega_c t) $$
2. **Phase Detector Implementation 2: Phase Detector**
- [DIAGRAM 3]
- $$ V_{FM}(t) + V_{FM}(t - T_0) $$
- $$ V_{FM}(t - T_0) $$
# Section 4: Zero Crossing Detector
- **Zero Crossing Detector**
- Utilizes the zero crossing of the FM wave to achieve frequency demodulation.
- Linear Range (f ~ V) is large, easy to integrate.
- **Feedback Phase Detector:** First phase detection, then differentiation.
- See PLL, PD output is a phase difference voltage.
Page 52
3. Digital Modulation
ASK.
- Frequency Demodulator
- Sampler
- Decision器
FSK (fm = fc + af: 信号; fs = fc - af: 信号) MF = 2fd / fs
DBPSK.
- 1bit延时
QPSK.
- 跳并转换
- sinout
- cosout
7. Loop Filter
1. Overview.
Feedback control system: AGC, AFC, APC → PLL.
Among them, PLL: narrowband (noise, frequency combination), loop filter, signal detection.
2. PLL Basic Principles.
1. PD: Phase detector, low-pass filter
2. LF: Loop filter, low-pass filter in the loop, part of the loop filter memory
3. VCO: Voltage-controlled oscillator
3. PLL Linear Analysis.
When θe is small, f[θe(t)] ≈ k_d θe(t) + s[θe(t)] + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k_d H[θe(t)] = s[θe(t)]
θe(t) + k_w k
Page 53
**Mathematical Formulas:**
1) RC Integrator LF:
$$H_{IF}(s) = \frac{1}{1+s\tau}$$
$$\tau = RC$$
$$H(s) = \frac{\omega_n^2}{s^2 + 2\zeta\omega_n s + \omega_n^2}$$
$$\omega_n^2 = \frac{K_p}{2}$$
$$H_{IF}(s) = \frac{s^2}{s^2 + 2\zeta\omega_n s + \omega_n^2}$$
$$2\zeta\omega_n = \frac{1}{2}$$
2) RC Differentiator LF:
$$H_{IF}(s) = \frac{1+s\tau}{1+s(\tau_1+\tau_2)}$$
$$\tau = RC, \tau_2 = RC$$
$$H(s) = \frac{(2\zeta-\omega_n/K_p)\omega_n s + \omega_n^2}{s^2 + 2\zeta\omega_n s + \omega_n^2}$$
$$\omega_n^2 = \frac{K_p}{\tau_1+\tau_2}$$
$$H_{IF}(s) = \frac{s^2 + s\omega_n^2/K_p}{s^2 + 2\zeta\omega_n s + \omega_n^2}$$
$$2\zeta\omega_n = \frac{1+K_p\tau_2}{\tau_1+\tau_2}$$
3) Ideal Integrator LF:
$$H_{IF}(s) = \frac{1+s\tau}{s\tau}$$
$$\tau = RC, \tau_2 = RC$$
$$H(s) = \frac{\omega_n^2}{s^2 + 2\zeta\omega_n s + \omega_n^2}$$
$$\omega_n^2 = \frac{K_p}{\tau_1}$$
$$H_{IF}(s) = \frac{s^2}{s^2 + 2\zeta\omega_n s + \omega_n^2}$$
$$2\zeta\omega_n = \frac{K_p\tau_2}{\tau_1}$$
4) Ideal Differentiator LF:
$$H_{IF}(s) = 1$$
$$H(s) = \frac{K_p}{s + K_p}$$
$$H_{IF}(s) = \frac{s}{s + K_p}$$
5) PLL Frequency Characteristics:
$$\varphi_{IF}(s) = \frac{\Delta\Omega}{s}$$
$$\varphi_{IF}(s) = \frac{\Delta\Omega}{s} \cdot H(s)$$
$$\varphi_{IF}(s) = \varphi_{IF} = 0$$
6) PLL Phase Characteristics:
$$\varphi_{IF}(s) = \frac{\Delta\Omega}{s}$$
$$\varphi_{IF}(s) = \frac{\Delta\Omega}{s} \cdot H(s)$$
$$\varphi_{IF}(s) = \varphi_{IF} = 0$$
7) PLL Frequency Characteristics:
$$\varphi_{IF}(s) = \frac{\Delta\Omega}{s}$$
$$\varphi_{IF}(s) = \frac{\Delta\Omega}{s} \cdot H(s)$$
$$\varphi_{IF}(s) = \varphi_{IF} = 0$$
8) PLL Phase Characteristics:
$$\varphi_{IF}(s) = \frac{\Delta\Omega}{s}$$
$$\varphi_{IF}(s) = \frac{\Delta\Omega}{s} \cdot H(s)$$
$$\varphi_{IF}(s) = \varphi_{IF} = 0$$
**Chinese Text:**
(Subject: ) Math Homework Paper
(Subject: ) Stability
(Subject: ) Closed-loop Transfer Function
(Subject: ) Ideal Integrator LF
(Subject: ) Ideal Differentiator LF
(Subject: ) PLL Frequency Characteristics
(Subject: ) PLL Phase Characteristics
Page 54
5. PLL's stability.
- First-order loop stable. 90°
- Second-order loop due to parasitic capacitance may not be stable. 180°
6. PLL's noise characteristics.
- Input noise < closed-loop transfer function. H(s)
- VCO phase noise < open-loop transfer function. H(s)
4. PLL's nonlinearity analysis.
- Tracking: lock → relock = linear (ωio = ωoo) → capture
- Capture: unlock → lock = nonlinear. (ωio ≠ ωoo) → capture
- Fast capture range ≤ capture range ≤ lock range.
- Capture range: maximum initial frequency difference that can enter the lock range.
- Fast capture range: within 2π can enter the lock range.
7. First-order loop nonlinearity analysis (eg. phase detection).
$$\varphi_e(t) + K_p \sin(\varphi_e(t)) = \Delta \omega_i = \omega_{io} - \omega_{oo}$$
$$\varphi_e(t) - \varphi_e(t) \text{ graph: }$$
$$\varphi_{eq} = \arcsin \frac{\Delta \omega_i}{K_p} + 2n\pi. (\varphi_e = 0)$$
5. Integrated phase-locked loop.
6. Phase-locked loop applications.
1. Narrowband tracking filter - narrowband tracking loop (carrier tracking).
2. Solve the problem of the center frequency change in general receivers and the widening of the intermediate frequency bandwidth, which affects the signal-to-noise ratio.
Page 55
**2. Carrier Recovery - Wideband Loop (Carrier Tracking)**
1. **Direct Frequency Synthesis**: Mixer + Divider / Divider + Filter
1) **Phase Loop**: Phase Locked Loop (PLL)
- Advantage: Fast
- Disadvantage: High frequency noise, phase shift large, complex structure
2) **Costas Loop**: Various digital modulation signals
- Advantage: Simple structure, high purity, high frequency
- Disadvantage: Slow tracking
3. **Phase Locked Loop (PLL)**
- Advantage: Simple structure, high purity, high frequency
- Disadvantage: Slow tracking
4. **Direct Digital Frequency Synthesis**
**2. Main Technical Indicators**
1. Frequency Range, Frequency Resolution ~ Reference Frequency (Reference), Conversion Time ~ Reference Frequency (PLL), Frequency Stability, Spectral Purity
$$ H_n(\cos\alpha + \alpha) = \frac{1}{1 + \alpha^2} \left( \frac{1}{2} \cos\alpha \right)^2 $$
2. AFC
- Advantage: High output frequency, low phase noise
- Disadvantage: High phase noise
3. **Phase Locked Loop (PLL)**
1. **Phase Locked Loop (PLL)**
- Advantage: High output frequency, low phase noise
- Disadvantage: High phase noise
2. **Phase Locked Loop (PLL)**
- Advantage: High output frequency, low phase noise
- Disadvantage: High phase noise
3. **Phase Locked Loop (PLL)**
- Advantage: High output frequency, low phase noise
- Disadvantage: High phase noise
4. **Phase Locked Loop (PLL)**
- Advantage: High output frequency, low phase noise
- Disadvantage: High phase noise
**8. Frequency Synthesis Technology**
1. **Phase Locked Loop (PLL)**
- Advantage: High output frequency, low phase noise
- Disadvantage: High phase noise
2. **Phase Locked Loop (PLL)**
- Advantage: High output frequency, low phase noise
- Disadvantage: High phase noise
3. **Phase Locked Loop (PLL)**
- Advantage: High output frequency, low phase noise
- Disadvantage: High phase noise
4. **Phase Locked Loop (PLL)**
- Advantage: High output frequency, low phase noise
- Disadvantage: High phase noise
**8. Frequency Synthesis Technology**
1. **Phase Locked Loop (PLL)**
- Advantage: High output frequency, low phase noise
- Disadvantage: High phase noise
2. **Phase Locked Loop (PLL)**
- Advantage: High output frequency, low phase noise
- Disadvantage: High phase noise
3. **Phase Locked Loop (PLL)**
- Advantage: High output frequency, low phase noise
- Disadvantage: High phase noise
4. **Phase Locked Loop (PLL)**
- Advantage: High output frequency, low phase noise
- Disadvantage: High phase noise
**8. Frequency Synthesis Technology**
1. **Phase Locked Loop (PLL)**
- Advantage: High output frequency, low phase noise
- Disadvantage: High phase noise
2. **Phase Locked Loop (PLL)**
- Advantage: High output frequency, low phase noise
- Disadvantage: High phase noise
3. **Phase Locked Loop (PLL)**
- Advantage: High output frequency, low phase noise
- Disadvantage: High phase noise
4. **Phase Locked Loop (PLL)**
- Advantage: High output frequency, low phase noise
- Disadvantage: High phase noise
**8. Frequency Synthesis Technology**
1. **Phase Locked Loop (PLL)**
- Advantage: High output frequency, low phase noise
- Disadvantage: High phase noise
2. **Phase Locked Loop (PLL)**
- Advantage: High output frequency, low phase noise
- Disadvantage: High phase noise
3. **Phase Locked Loop (PLL)**
- Advantage: High output frequency, low phase noise
- Disadvantage: High phase noise
4. **Phase Locked Loop (PLL)**
- Advantage: High output frequency, low phase noise
- Disadvantage: High phase noise
Page 2
Title Page: Angli Liu (Angli Liu)
Page 3
**Review of Electromagnetism**
**I. Introduction**
Radiation: Source → Space
Absorption: Space → Source
**II. Radiation Field**
1. Vector Quantities of Electric Current Source and Magnetic Current Source
Let $$\vec{H}_e = \frac{1}{\mu} \nabla \times \vec{A}_e$$
Substitute
$$\nabla \times \vec{E}_e = -j\omega \mu \vec{H}_e$$
Result in
$$\nabla \times (\vec{E}_e + j\omega \vec{A}_e) = 0$$
Let $$\vec{E}_e + j\omega \vec{A}_e = -\nabla \phi_e$$
Substitute
$$\nabla \times \vec{H}_e = j\omega \varepsilon \vec{E}_e + \vec{j}_e$$
Result in
$$\frac{1}{\mu} \nabla \times \nabla \times \vec{A}_e = j\omega \varepsilon (-\nabla \phi_e - j\omega \vec{A}_e) + \vec{j}_e$$
Thus
$$\nabla^2 \vec{A}_e + k^2 \vec{A}_e = -\mu \vec{j}_e + \nabla (\nabla \cdot \vec{A}_e + j\omega \varepsilon \mu \phi_e)$$
Lorentz gauge
$$\nabla \cdot \vec{A}_e + j\omega \varepsilon \mu \phi_e = 0$$
Result in
$$\nabla^2 \vec{A}_e + k^2 \vec{A}_e = -\mu \vec{j}_e$$
$$\phi_e = -\frac{1}{j\omega \varepsilon \mu} \nabla \cdot \vec{A}_e$$
Substitute
$$\vec{E}_e + j\omega \vec{A}_e = -\nabla \phi_e$$
Result in
$$\vec{E}_e = -j\omega \vec{A}_e - \frac{1}{c \omega \mu} \nabla (\nabla \cdot \vec{A}_e)$$
Solve (2) to get
$$\vec{A}_e(\vec{r}) = \frac{\mu}{4\pi} \int \frac{\vec{e}_k (\vec{r} - \vec{r}')}{|\vec{r} - \vec{r}'|} \vec{j}(\vec{r}') d\vec{r}'$$
Substitute (5) into (1) and (4) to obtain the electric field $$\vec{E}_e$$ and magnetic field $$\vec{H}_e$$ generated by the electric current source $$\vec{j}_e$$.
Let $$\vec{E}_m = -\frac{1}{\varepsilon} \nabla \times \vec{A}_m$$
Substitute
$$\nabla \times \vec{H}_m = j\omega \varepsilon \vec{E}_m$$
Result in
$$\nabla \times (j\vec{H}_m + j\omega \vec{A}_m) = 0$$
Let $$\vec{H}_m + j\omega \vec{A}_m = -\nabla \phi_m$$
Substitute
$$\nabla \times \vec{E}_m = -j\omega \mu \vec{H}_m - \vec{j}_m$$
Page 4
Here's the extracted text and formulas from the handwritten note, with placeholders for the diagram:
---
\begin{equation}
-\frac{1}{2} \nabla \times \nabla \times \vec{A}_m = -j \omega \mu (\nabla \phi_m - j \omega \vec{A}_m) - \vec{J}_m
\end{equation}
\begin{equation}
\nabla^2 \vec{A}_m + k^2 \vec{A}_m = -\epsilon \vec{J}_m + \nabla (\nabla \cdot \vec{A}_m + j \omega \epsilon \mu \phi_m)
\end{equation}
\begin{equation}
\nabla \cdot \vec{A}_m + j \omega \epsilon \mu \phi_m = 0
\end{equation}
\begin{equation}
\nabla^2 \vec{A}_m + k^2 \vec{A}_m = -\epsilon \vec{J}_m = \nabla \cdot \vec{E}_m
\end{equation}
\begin{equation}
\phi_m = -\frac{1}{j \omega \epsilon \mu} \nabla \cdot \vec{A}_m
\end{equation}
\begin{equation}
\vec{H}_m + j \omega \vec{A}_m = -\nabla \phi_m
\end{equation}
\begin{equation}
\vec{H}_m = -j \omega \vec{A}_m - \frac{1}{\epsilon \mu} \nabla (\nabla \cdot \vec{A}_m)
\end{equation}
\begin{equation}
\vec{A}_m(\vec{r}) = \frac{1}{4 \pi} \int \frac{\vec{J}_m(\vec{r}')}{|\vec{r} - \vec{r}'|} dV'
\end{equation}
\begin{equation}
\text{Substitute (12) into (11) and (10) to obtain the electric field } \vec{E}_m \text{ and magnetic field } \vec{H}_m \text{ due to the magnetic current source } \vec{J}_m.
\end{equation}
---
\section{Electric Dipole Radiation Field}
\subsection{Electric Dipole: A long, thin wire with a uniform current density I.}
\begin{equation}
\vec{A}(\vec{r}) = \frac{\mu I e^{-jkr}}{4 \pi r} \hat{z} = A_z \hat{z}
\end{equation}
\begin{equation}
A_z = A_2 \cos \theta = \frac{\mu I e^{-jkr}}{4 \pi r} \cos \theta
\end{equation}
\begin{equation}
A_\theta = -A_2 \sin \theta = -\frac{\mu I e^{-jkr}}{4 \pi r} \sin \theta
\end{equation}
\begin{equation}
A_\phi = 0
\end{equation}
\begin{equation}
\vec{E}_\phi = \vec{H}_\theta = \vec{H}_\phi = 0
\end{equation}
\begin{equation}
\text{Near-field } kr < 1:
\end{equation}
\begin{equation}
\begin{cases}
E_r \approx -j \eta \frac{2 I e^{-jkr}}{4 \pi k r^3} \cos \theta \\
E_\theta \approx -j \eta \frac{2 I e^{-jkr}}{4 \pi r^2} \frac{2}{k r} \cos \theta \\
E_\phi \approx \frac{2 I e^{-jkr}}{4 \pi r^2} \left( \frac{j \omega \mu}{r} + \frac{1}{r^2} + \frac{j \omega \epsilon r^3}{\eta} \right) \sin \theta
\end{cases}
\end{equation}
\begin{equation}
\text{Far-field } kr >> 1:
\end{equation}
\begin{equation}
\begin{cases}
E_r \approx 0 \\
E_\theta \approx j \eta \frac{k I e^{-jkr}}{4 \pi r^2} \sin \theta \\
E_\phi \approx \frac{E_\theta}{\eta}
\end{cases}
\end{equation}
Page 5
The note appears to be a detailed mathematical derivation related to electromagnetic fields and antenna theory. Here's the extracted text and formulas:
---
By
$$\vec{S} = \frac{1}{2} (\vec{E} \times \vec{H}^*) = \hat{r} S_r + \hat{\theta} S_\theta + \hat{\phi} S_\phi$$
We get
$$\begin{cases}
S_r = \frac{1}{2} E_0 H_\phi^* = \frac{\eta}{8} \left(\frac{2\pi}{\lambda}\right)^2 \frac{\sin^2\theta}{r^2} \left[1 - j\left(\frac{1}{kr}\right)^3\right] \\
S_\theta = -\frac{1}{2} E_r H_\phi^* = j\eta \left[\frac{kI r^2 \cos\theta \sin\theta}{16\pi^2 r^3}\right] \left[1 + \left(\frac{1}{kr}\right)^2\right]
\end{cases}$$
The total radiated power
$$P = \oint \vec{S} \cdot d\vec{S} = \int_0^{2\pi} d\phi \int_0^\pi \vec{S} \cdot \hat{r} r^2 \sin\theta d\theta$$
$$= \eta \frac{\pi}{3} \left(\frac{2\pi}{\lambda}\right)^2 \left[1 - j\left(\frac{1}{kr}\right)^3\right]$$
The real part is the electric dipole radiated power
$$P_{rad} = \eta \frac{\pi}{3} \left(\frac{2\pi}{\lambda}\right)^2$$
$$= \frac{1}{2} \left[\eta \frac{2\pi}{3} \left(\frac{2\pi}{\lambda}\right)^2\right] I^2$$
$$= \frac{1}{2} \left[80\pi^2 \left(\frac{2\pi}{\lambda}\right)^2\right] I^2$$
---
Three. Antenna Basic Parameters (1)
1. **Radiation Pattern**
1. **Far Field Region**
In the far field, E, H only have θ, φ components
$$\vec{E} = \hat{\theta} E_\theta + \hat{\phi} E_\phi$$
$$\vec{H} = \frac{1}{\eta} (\hat{\phi} E_\theta - \hat{\theta} E_\phi)$$
$$\vec{S} = \frac{1}{2} (\vec{E} \times \vec{H}^*) = \frac{1}{2} \left( |E_\theta|^2 + |E_\phi|^2 \right)$$
2. **Near Field Region**
$$E_\theta = \frac{f_0 (\cos\theta) e^{-jkr}}{r}$$
$$E_\phi = \frac{f_0 (\cos\phi) e^{-jkr}}{r}$$
$$\therefore S_r = \frac{1}{2\eta r^2} \left( |H_\theta (\cos\theta) e^{-jkr}|^2 + |H_\phi (\cos\phi) e^{-jkr}|^2 \right)$$
**Radiated Power Pattern**
$$F(\theta, \phi) = r^2 S_r = \frac{1}{2\eta} \left( |f_\theta (\cos\theta) e^{-jkr}|^2 + |f_\phi (\cos\phi) e^{-jkr}|^2 \right)$$
**Normalized Radiation Pattern**
$$F_n(\theta, \phi) = \frac{F(\theta, \phi)}{F_{max}(\theta, \phi)} = S_n / S_{max}$$
(3D Diagram, Polar Diagram)
**For Dipole Antenna**
$$F_n(\theta, \phi) = \sin^2\theta$$
$$\vec{E} \text{ field} \quad \phi = const$$
$$\vec{H} \text{ field} \quad \theta = 90^\circ$$
---
2. **Wire Antenna Radiation Pattern**
Page 6
The note discusses various aspects of antenna theory, including:
1. **Solid Angles:**
- **Total Solid Angle:** \( \Omega_T = \int_{4\pi} F_n(\theta, \phi) d\Omega \)
- **Main Solid Angle:** \( \Omega_M = \int_{\Omega} F_n(\theta, \phi) d\Omega \)
- **Normal Solid Angle:** \( \Omega_N = \int_{\Omega} F_n(\theta, \phi) d\Omega \)
2. **Directionality:**
- **Radiation Power Density:** \( D(\theta, \phi) = \frac{S_r(\theta, \phi)}{P_r / 4\pi r^2} \)
- **Antenna Efficiency:** \( \eta_e = \frac{P_e}{P_m} \)
- **Maximum Directionality:** \( D_0 = \frac{4\pi}{\Omega_T} \)
3. **Gain:**
- **Efficiency:** \( \eta_e = \frac{P_e}{P_m} \)
4. **Antenna Polarization:**
- **Maximum Gain Direction:** \( \frac{S_r(\theta, \phi)}{F_n(\theta, \phi)} \)
5. **Antenna Input Impedance:**
- **Input Impedance:** \( R_{in} \) depends on the radiation resistance and the resistance of the antenna.
Page 7
The page contains a detailed mathematical analysis of antenna radiation patterns and impedance calculations. It discusses the far-field radiation pattern of a dipole antenna and the radiation resistance of a half-wave dipole antenna. The formulas include expressions for the electric field, magnetic field, and radiation resistance. The text also mentions the concept of a two-element array and its radiation pattern. The page is filled with complex mathematical derivations and equations, including integrals and trigonometric functions. The bottom part of the page discusses the radiation resistance of a dipole antenna and the input impedance of a two-element array. The formulas are written in a structured format, with each step clearly delineated. The page is a comprehensive study of antenna theory, focusing on the radiation pattern and impedance of various antenna configurations.
Page 8
$$\approx j\frac{\eta kZ\varphi}{4\pi r}e^{jkr}\sin\theta\left[e^{j\left(kd\cos\theta+\beta\right)/2}+e^{-j\left(kd\cos\theta+\beta\right)/2}\right]$$
$$=j\frac{\eta kZ\varphi}{4\pi r}e^{jkr}\sin\theta\cdot2\cdot\cos\left(kd\cos\theta+\beta\right)/2$$
$$=j\frac{\eta kZ\varphi}{4\pi r}e^{jkr}f(\theta,\varphi)$$
2. N-element array
$$f_A(\psi)=a_0+a_1e^{j\psi}+\ldots+a_Ne^{j(N-1)\psi},\quad\psi=kd\cos\theta+\beta$$
When equal amplitude: $$f_A(\psi)=\frac{\sin\left(N\psi/2\right)}{\sin\left(\psi/2\right)}$$
Normalization: $$f_A(\psi)=\frac{1}{N}\frac{\sin\left(N\psi/2\right)}{\sin\left(\psi/2\right)}=\text{Sa}\left(N\psi/2\right)$$
Main lobe maximum: $$\psi=0$$
Null points: $$\frac{N\psi}{2}=p\pi,\quad p=\pm1,\pm2,\ldots,\pm\frac{N}{2}$$
Side lobe maximum: $$\frac{N\psi}{2}=2p+1\pi,\quad p=1,\pm2,\ldots,-\frac{N}{2}$$
7. Horn antenna
$$\begin{cases} \text{Azimuth: } r\approx r_0-r'\cos\beta=r_0-\vec{r'}\cdot\hat{F} \\ \text{Elevation: } r\approx r_0 \end{cases}$$
$$\begin{cases} \vec{A_e}=\frac{\mu}{4\pi}\int_S\vec{J_{es}}\frac{e^{jkr}}{r}ds' \approx\frac{\mu e^{jkr_0}}{4\pi r_0}\int_S\vec{J_{es}}\cdot e^{jkr_0}ds' \\ \vec{A_m}=\frac{\varepsilon}{4\pi}\int_S\vec{J_{ms}}\frac{e^{jkr}}{r}ds' \approx\frac{\varepsilon e^{-jkr_0}}{4\pi r_0}\int_S\vec{J_{ms}}\cdot e^{jkr_0}ds' \end{cases}$$
$$r'\cos\beta=\vec{r'}\cdot\hat{F}=x'\sin\theta\cos\varphi+y'\sin\theta\sin\varphi$$
By the principle of equivalent current density: $$\vec{J_{ms}}=-2\hat{x}\times\vec{E_a},\quad\vec{J_{es}}=0$$
Rectangular horn, uniform field distribution: $$\vec{J_{ms}}=-2\hat{x}\times\vec{E_a}=\hat{x}\cdot2\vec{E_0}$$
$$\vec{A_m}=\hat{x}\frac{\varepsilon e^{-jkr_0}}{4\pi r_0}\int_{-\frac{a}{2}}^{\frac{a}{2}}\int_{-\frac{b}{2}}^{\frac{b}{2}}2\vec{E_0}e^{-jkr_0}(\cos\varphi\cos\varphi+\sin\varphi\sin\varphi)dx'dy'$$
$$\vec{A_e}=\hat{x}\frac{\mu e^{jkr_0}}{4\pi r_0}\int_{-\frac{a}{2}}^{\frac{a}{2}}\int_{-\frac{b}{2}}^{\frac{b}{2}}2\vec{E_0}e^{jkr_0}(\cos\varphi\cos\varphi+\sin\varphi\sin\varphi)dx'dy'$$
$$\vec{E_\varphi}\approx-j\omega\eta A_m\varphi=j\frac{\omega\mu kE_0e^{-jkr_0}}{2\pi r_0}\cos\varphi\cos\varphi\sin\varphi\sin\varphi$$
$$H_\varphi\approx-\vec{E_\varphi}/\eta$$
Page 9
Chapter 13. Microwave Antennas
# 1. Rectangular Microstrip Structure
- **Resonant Frequency**:
$$ f_{res} = \frac{c}{2\pi\sqrt{\epsilon_r} \cdot w} $$
Where \( c \) is the speed of light, \( \epsilon_r \) is the relative permittivity of the substrate, and \( w \) is the width of the microstrip line.
- **Substrate**:
$$ \epsilon_r > 1 $$
- **Ground Plane**:
$$ \Delta \phi = 0^\circ $$
# 2. Advantages
- a. Has a planar structure, suitable for missiles, satellites, and other flat objects.
- b. Suitable for printed circuit board production.
- c. Suitable for forming antenna arrays.
- d. Wide bandwidth, low power density, low radiation efficiency.
# 3. Analysis Methods and Radiation Patterns
- **Transmission Line Model**:
- Treats the microstrip as a single antenna (half-wave dipole).
- Radiation efficiency is low.
- **Electric Field Distribution**:
- For \( \theta = 90^\circ \), the electric field distribution is:
$$ E = \frac{1}{2} \cos\left(\frac{\pi b}{2} \sin\theta\right) - 2 \cos\left(\frac{\pi d}{2} \sin\theta\right) $$
- **Radiation Pattern**:
- For \( \theta = 90^\circ \), the radiation pattern is:
$$ f_{rad} = f_{rad}(0) \cdot 2 = S \cos\left(\frac{\pi b}{2} \sin\theta\right) - 2 \cos\left(\frac{\pi d}{2} \sin\theta\right) $$
Page 10
4. Impedance Matching and Input Impedance
A. Impedance Matching Network and Its Input Impedance
$$
\frac{R_{c}}{2} \quad \text{and} \quad \left(\frac{R_{c}}{2}\right)
$$
$$
\text{Input Impedance} \quad Z_{in} = \frac{R_{c}}{2} \quad (\because l = \frac{\lambda}{2}, \text{antenna resonant when } X_{in} = 0, \text{two } R_{c} \text{ in parallel})
$$
$$
R_{c} \approx 120 \frac{\lambda}{W} \Omega \quad (W \geq 2\lambda)
$$
$$
R_{c} \approx 90 \left(\frac{\lambda}{W}\right)^2 \Omega \quad (W < 0.35\lambda)
$$
$$
R_{c} \approx \frac{W}{120\lambda - \frac{1}{60\pi^2}} \Omega \quad (0.35\lambda \leq W < 2\lambda)
$$
Changing \( R_{c} \) can adjust \( W \), thus adjusting the frequency.
5. Transmission Line Types
a) Sideband
$$
Z_{c} = 50 \Omega \quad \text{and} \quad \text{antenna bandwidth}
$$
b) Bottomband
$$
Z_{c} = 50 \Omega \quad \text{and} \quad \text{antenna bandwidth}
$$
6. Polarization Techniques
a) T-shaped branch line
b) Branch line bridge
Page 11
c) 4-element array circular polarization antenna
7. Circular polarization measurement method.
Rotate the circular polarization antenna to measure the radiation intensity at different angles.
8. Broadband, dual-band antenna.
Stacking method for broadband:
- When the two boards are close, it's broadband.
- When the two boards are far apart, it's dual-band.
9. Antenna array.
16-element array antenna, T-shaped branch and parallel connection
$$E_1$$ $$E_2$$ $$E_3$$ Circular polarization.
Page 12
1. Introduction
# 1.1. Parabolic Reflector
- **Parabolic Reflector**:
- **Focus Point**: The point where all reflected rays converge.
- **Focal Length**: The distance from the focus to the vertex of the parabola.
- **Aperture**: The opening of the parabolic reflector.
- **Wavefront**: The surface of constant phase of a wave.
# 1.2. Optical Properties of Parabolic Reflectors (Applicable to Centimeter and Millimeter Waves)
1. **Reflection of Parallel Rays**: Parallel rays entering the parabolic reflector are reflected and converge at the focus.
2. **Focal Length**: The distance from the focus to the vertex of the parabola is 2f.
2. Various Types of Parabolic Reflectors
# 2.1. (a) Pinhole Beam
- **Applications**: Radar, satellite communication.
- **Beam Pattern**: The beam pattern is a circular pattern.
# 2.2. (b) Vertical Fan Beam
- **Applications**: Radar, phased array.
- **Beam Pattern**: The beam pattern is a vertical fan pattern.
# 2.3. (c) Slotted Parabolic Reflectors
- **Applications**: Through the slotted beam.
- **Beam Pattern**: The beam pattern is a slotted beam pattern.
# 2.4. (d) Parabolic Cylinder
- **Applications**: Radar, phased array.
- **Beam Pattern**: The beam pattern is a cylindrical beam pattern.
Page 13
3. Methods to reduce wind resistance and weight.
Metal plate structure. E: vertical polarization or reflection. Wavelength shorter, hole smaller.
$$\int |E| \propto e^{-\alpha l}$$
$$P \propto e^{-2\alpha l}$$
Reduce wind resistance. $$\alpha < \frac{1}{2} \Rightarrow \alpha < \frac{1}{4} (\frac{1}{8} \sim \frac{1}{10})$$
Drill holes. $$\alpha < \frac{1}{2} \Rightarrow \alpha < \frac{1}{4} (\frac{1}{8} \sim \frac{1}{10})$$
4. Different distances of parabolic reflector antenna.
(a) Medium distance. $$\psi_0 = \frac{\pi}{2}, f/D = 0.25$$
(b) Long distance. $$\psi_0 < \frac{\pi}{2}, f/D > 0.25$$
(c) Short distance. $$\psi_0 > \frac{\pi}{2}, f/D < 0.25$$
5. Different distances of parabolic reflector antenna (polarization distribution).
(a) Medium distance. Mainly linear polarization. Polarization: at the edge.
(b) Long distance. Linear polarization less.
(c) Short distance. Linear polarization more. Reverse polarization less.
6. Load power and leakage power.
$$\eta_A = P_{rs} (\text{receiver power}) / P_r (\text{transmitter power})$$
$$\eta_A = P_{rs} (\text{receiver power}) / P_r (\text{transmitter power})$$
Page 14
7. Interference and elimination of sources on the same side of the wavefront. Problem: shadowing, reflection, and interference of sources.
1. Install a hole in the wavefront.
2. Install a compensating disc before installation.
3. Eliminate the source method.
S = π²/4C (source area) d = √(4π²/λ), l = (2n+1)π/4 - π/4. Φ = a1(π/4)² + a2(π/4) - a3(π)
8. Find the far-field radiation pattern of a parabolic antenna.
1. Near-field method.
E.H = 0.
E + H ∈ plane of the hole.
Jes = H × Ha = Jms = H × Ea
Am - A
E - H
a. Find the surface of E and H in the near-field and far-field regions.
b. In the plane of the hole, E and H are zero.
c. Use the principle of electric field source and image theorem to find Jes and Jms.
d. Use Jms to find Am and Jms.
e. Use Am to find A and calculate E and H.
II. Mirror surface current flow:
a. Js = (n × H) + (n × H)
= 2(n × H) + (n × H)
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Page 15
**815. Cassegrainian Telescope**
**1. Structural Design Principles**
(1) To (8) Wavefronts (Real Source)
(2) Virtual Source
(3) Secondary Reflective Surface (Double Surface)
**2. Advantages:**
1) The surface distribution is adjusted to the best, with two reflective surfaces adjustable.
2) Compact structure, light weight - tail
3) Good resistance - double surface for broad reflection.
4) "Long distance parabolic surface optical performance" and "mechanical performance" are good.
**3. Two Analysis Methods:**
a. Virtual Source Method (Equivalent Source Method).
b. Parabolic Surface Method.
**4. The distance of the secondary reflective surface can be solved by "rotating 90°" method.**
shows the equivalent parabolic surface. The source, double surface, parabolic surface, and the tail are fixed, and the equivalent parabolic surface is drawn.
illustrates the rotation of the parabolic surface by 90°.
depicts the relationship between the parabolic surface and the tail.
Page 16
The page contains a series of diagrams and notes. Here's the extracted text and formulas:
1. Diagram 1:
- The diagram shows a circular object with a vertical line through its center. There are arrows pointing to different parts of the circle, indicating various measurements and angles. One of the arrows is labeled "α<π/2". There's also a smaller diagram within the main circle, showing a vertical line and a horizontal line intersecting at a right angle. The text next to this smaller diagram says "Plane: Polarization rotated 90°".
2. Diagram 2:
- This diagram appears to be a 3D geometric figure, possibly a cube or a rectangular prism, with various lines and arrows indicating different planes and axes. The text next to it is partially obscured but seems to describe the relationships between the different planes and axes.
3. Diagram 3:
- This diagram shows a rectangular object with a curved line drawn on it. There are arrows pointing to different parts of the rectangle and the curved line. The text next to it is not fully legible but seems to describe the relationship between the rectangle and the curved line.
4. Diagram 4:
- This diagram shows a circular object with a vertical line through its center. There are arrows pointing to different parts of the circle, indicating various measurements and angles. One of the arrows is labeled "α<π/2". There's also a smaller diagram within the main circle, showing a vertical line and a horizontal line intersecting at a right angle. The text next to this smaller diagram says "Plane: Polarization rotated 90°".
5. Diagram 5:
- This diagram appears to be a 3D geometric figure, possibly a cube or a rectangular prism, with various lines and arrows indicating different planes and axes. The text next to it is partially obscured but seems to describe the relationships between the different planes and axes.
Page 17
15
**Initial Review**
**1. Transfer Function:**
$$
\frac{Z_{1}dz}{C_{1}dz} \quad R_{1}dz \quad Z
$$
When open: \( R_{1} = C_{1} = 0 \)
$$
C_{1}dz = \frac{F}{F} \quad G_{1}dz \quad V
$$
**Domain:**
Capacitor: \( V(j\omega) = -\frac{1}{j\omega C} I(j\omega) \)
Inductor: \( V(j\omega) = j\omega L I(j\omega) \)
Resistor: \( V(j\omega) = R I(j\omega) \)
**Domain Transfer Function:**
$$
dV(j\omega, z) = I(j\omega) j\omega L dz
$$
$$
dI(j\omega, z) = V(j\omega, z) j\omega C_{1} dz
$$
Solve
$$
V(j\omega, z) = V_{0+}(j\omega) e^{j\omega\sqrt{L C_{1}} z} + V_{0-}(j\omega) e^{-j\omega\sqrt{L C_{1}} z}
$$
$$
I(j\omega, z) = I_{0+}(j\omega) e^{j\omega\sqrt{L C_{1}} z} + I_{0-}(j\omega) e^{-j\omega\sqrt{L C_{1}} z}
$$
$$
Z_{c} = \frac{1}{j\omega C_{1}}, \quad \omega = \frac{1}{\sqrt{L C_{1}}}
$$
$$
V_{+}(j\omega, z) \triangleq V_{0+}(j\omega) e^{j\omega\sqrt{L C_{1}} z}, \quad V_{-}(j\omega, z) \triangleq V_{0-}(j\omega) e^{-j\omega\sqrt{L C_{1}} z}
$$
$$
I_{+}(j\omega, z) \triangleq \frac{V_{+}(j\omega, z)}{Z_{c}}, \quad I_{-}(j\omega, z) \triangleq \frac{V_{-}(j\omega, z)}{Z_{c}}
$$
Then
$$
V(j\omega, z) = V_{+}(j\omega, z) + V_{-}(j\omega, z)
$$
$$
I(j\omega, z) = I_{+}(j\omega, z) + I_{-}(j\omega, z)
$$
Boundary condition
$$
\begin{cases}
V(j\omega, 0) = V_{0+}(j\omega) + V_{0-}(j\omega) = I(j\omega, 0) Z_{c}(j\omega) \\
Z(j\omega, 0) = \frac{1}{Z_{c}} \left[ V_{0+}(j\omega) - V_{0-}(j\omega) \right]
\end{cases}
$$
$$
\begin{cases}
V(j\omega, t) = V_{0+}(j\omega) e^{j\omega\sqrt{L C_{1}} t} + V_{0-}(j\omega) e^{-j\omega\sqrt{L C_{1}} t} = V_{g}(j\omega) - I(j\omega) Z_{c}(j\omega) \\
Z(j\omega, t) = \frac{1}{Z_{c}} \left[ V_{0+}(j\omega) - V_{0-}(j\omega) \right]
\end{cases}
$$
$$
\frac{V_{0+}(j\omega) + V_{0-}(j\omega)}{Z_{c}(j\omega)} = \frac{V_{g}(j\omega)}{Z_{c}(j\omega)} - \frac{V_{0+}(j\omega) - V_{0-}(j\omega)}{Z_{c}(j\omega)}
$$
Page 18
Time Domain Operational Rules: (Time as variable, ω as constant).
# Voltage:
$$ V = V_0 \cos(\omega t) = Re(V_0 e^{j\omega t}) \quad , \quad \tilde{V} = V_0 e^{j\omega t} $$
$$ I = I_0 \cos(\omega t) = Re(I_0 e^{j\omega t}) \quad , \quad \tilde{I} = I_0 e^{j\omega t} $$
# Capacitance:
$$ \frac{dV(t)}{dt} = C \frac{dI(t)}{dt} $$
$$ I(t) = C \frac{dV(t)}{dt} = j\omega C \cdot Re(V_0 e^{j\omega t}) $$
$$ = j\omega C \cdot V_0 e^{j\omega t} $$
$$ \tilde{I}(t) = j\omega C \cdot V_0 e^{j\omega t} = j\omega C \cdot \tilde{V} $$
$$ V(t) = L \frac{dI(t)}{dt} $$
$$ \tilde{V}(t) = j\omega L \cdot \tilde{I} $$
# Inductance:
$$ V(t) = R I(t) $$
$$ \tilde{V}(t) = R \tilde{I}(t) $$
$$ e^{j\omega t} \text{ factor is linearly invariant, so } \tilde{V}(x, t), \tilde{I}(x, t) \text{ can be directly substituted into } V(x, t), I(x, t). $$
The above rules are the rules of "fields", similar to the rules of "circuits". Substitute directly into V(x, t), I(x, t).
Microwave Network Research Method.
To define the voltage and current of a single-mode waveguide mode on the reference surface of the waveguide and the mode current. Under the following rules: only consider propagation in one direction + or -.
(1) $$ V(x), \text{ and } E_T, \text{ and } I_T \text{ and } H_T $$
(2) $$ P = V(x) \cdot I(x) $$
(3) $$ Z_C = \frac{V(x)}{I(x)} $$
Entering the network: inward wave $$ a = V_+ / \sqrt{Z_C} $$, outward wave $$ a' = a e^{j\alpha}, b = b e^{j\beta} $$
Leaving the network: outward wave $$ b = V_- / \sqrt{Z_C} $$, inward wave $$ b' = b e^{j\beta}, a' = a e^{j\alpha} $$
Page 19
For N-terminal networks, define:
$$
\begin{pmatrix}
b_1 \\
\vdots \\
b_n
\end{pmatrix}
=
\begin{pmatrix}
s_{11} & s_{1n} \\
\vdots & \vdots \\
s_{n1} & s_{nn}
\end{pmatrix}
\begin{pmatrix}
a_1 \\
\vdots \\
a_n
\end{pmatrix}
\quad \text{and} \quad
\vec{b} = [s] \vec{a}
$$
For i in the network: s_{ii} = 0
For i in the network: r_i = 0
(1) Symmetry: s_{ij} = s_{ji}, [s] = [s]^{T}
(2) Unitarity: [s]^{H} [s] = I
For two-terminal networks:
$$
\begin{array}{c}
a_1 \rightarrow \frac{u_1}{v_1} \\
b_1 \leftarrow \frac{u_2}{v_2} \rightarrow b_2
\end{array}
$$
(1) Symmetry: s_{12} = s_{21}
(2) Unitarity: |s_{12}| = |s_{21}| > |s_{11}| = |s_{22}|, |s_{11}|^2 + |s_{22}|^2 = 1; |s_{12}|^2 + |s_{21}|^2 = 1
1) From port 1 to port 2, the voltage transmission coefficient is 1:
|s_{11}| = |s_{22}| = 0, |s_{12}| = |s_{21}| = 1.
2) Cannot achieve unidirectional isolation, isolation is bidirectional:
|s_{12}| = |s_{21}| = 0.
3) Bidirectional isolation, complete reflection:
|s_{12}| = |s_{21}| = 0, |s_{11}| = |s_{22}| = 1.
(3) Symmetry: s_{11} = s_{22}, s_{12} = s_{21}.
1) Characteristic equation:
\begin{pmatrix}
s_{11} - s_j & s_{12} \\
s_{12} & s_{11} - s_j
\end{pmatrix}
\begin{pmatrix}
u_i \\
u_j
\end{pmatrix}
= 0
2) Eigenvalues:
s_1 = s_{11} + s_{22} \Rightarrow s_1 = \frac{s_1 + s_2}{2}
s_2 = s_{11} - s_{12} \Rightarrow s_2 = \frac{s_1 - s_2}{2}
0 = s_1 - s_2
s_1 = s_2
Eigenvalues:
s_1 \Rightarrow u_1 = \frac{1}{\sqrt{2}} (1, 1)^T
s_2 \Rightarrow u_2 = \frac{1}{\sqrt{2}} (1, -1)^T
Meaning: Using u_1 as the two-terminal network's reflection coefficient b = [s] u_1 = s_1 u_1, the reflection coefficient is s_1.
Using u_2 as the two-terminal network's reflection coefficient b = [s] u_2 = s_2 u_2, the reflection coefficient is s_2.
For u_1, the two components of the two-terminal network are in the same direction, corresponding to the middle reflection situation.
Page 20
(4) Indicators:
1) Voltage transmission coefficient \( T_v = S_{21} \)
2) Power transmission coefficient \( T_p = |S_{21}|^2 \)
3) Insertion loss \( L = \frac{1}{15.41} \)
4) Insertion phase \( \phi_{21} = \arg S_{21} \)
5) Group delay \( t_d = \frac{d}{d\omega} \phi_{21} \)
6) Insertion loss ratio \( \rho = \frac{1}{1 - |T_{21}|} = \frac{1 + |S_{21}|}{1 - |S_{21}|} \)
(5) Impedance Matrix:
Series: \( [Z] = \sum [z] \)
\( V_p = V_q = 0 \): Effective series
Parallel: \( [Y] = \sum [y] \)
\( V_p = V_q = 0 \): Effective parallel
Cascade: \( [A] = \Pi [A_i] \) (where \( V_1, I_1, V_2, I_2 \) are represented)
Transmission Matrix:
Series: \( [T] = \Pi [t] \) (where \( a_1, b_1, a_2, b_2 \) are represented)
Series-parallel: \( [H] = \sum [h] \)
Parallel-series: \( [G] = \sum [g] \)
IV. Waveguide to Transmission Line (Time Delay, Phase, Lossless):
1. Cross relationship. (Example: \( \nabla = \nabla_1 + \nabla_2 \); \( \nabla = \nabla_1 + \nabla_2 \)).
Unknown, time delay:
Forward transmission (wave number \( k_1 \)):
\( \vec{H}_T = -\frac{jk_2}{k_1^2 - k_2^2} \nabla \cdot \vec{E}_2 - jk_2 \nabla \cdot \vec{H}_2 \)
\( \vec{E}_T = j\omega \mu \frac{1}{k_1^2 - k_2^2} \nabla \times \vec{H}_2 + jk_2 \nabla \times \vec{E}_2 \)
Backward transmission (wave number \( k_2 \)):
\( \vec{H}_T = j\omega \mu \frac{1}{k_1^2 - k_2^2} \nabla \times \vec{E}_2 + jk_2 \nabla \times \vec{H}_2 \)
\( \vec{E}_T = -j\omega \mu \frac{1}{k_1^2 - k_2^2} \nabla \times \vec{H}_2 + jk_2 \nabla \times \vec{E}_2 \)
2. TE mode: \( E_z = 0 \).
Forward transmission:
\( \vec{E}_T = -\frac{jk_2}{k_1^2 - k_2^2} \nabla \times \vec{H}_2 - \eta_{TE} \nabla \times \vec{H}_T \)
\( \vec{H}_T = \eta_{TE} \nabla \times \vec{E}_T \)
Boundary condition: \( \frac{\partial H_2}{\partial n} \mid_{z=0} = 0 \).
Page 21
The note discusses wave equations and their solutions in a medium, specifically focusing on TE and TM waves. It includes the following key points:
1. TE wave: E2 = 0. The wave equation is ∇²H2 + k²H2 = 0. The solution is H2 = H2(τ) * e^(-jkz). The boundary condition is ∂H2/∂n = 0 at the boundary. The reflection and transmission coefficients are defined as ηTE(∞) = w/k.
2. TM wave: H2 = 0. The wave equation is ∇²E2 + k²E2 = 0. The solution is E2 = E2(τ) * e^(-jkz). The boundary condition is E2 = 0 at the boundary. The reflection and transmission coefficients are defined as ηTM(∞) = k/2w.
3. TEM wave: E2 = 0, H2 = 0. The wave equation is ∇²W + k²W = 0. The solution is W = W(τ) * e^(-jkz). The boundary condition is ∂W/∂n = 0 at the boundary. The reflection and transmission coefficients are defined as ηTEM = √(w/k).
4. The wave equations for TE and TM waves are given as:
- TE wave: (k² - k²)H = -jwε/2 * ∇E - jk²∇H.
- TM wave: (k² - k²)E = jwε/2 * ∇H + jk²∇E.
5. The wave number k is defined as k = √(k² - k²). The cutoff wave number is defined as k = √(k² - k²). The cutoff frequency is defined as f = k²/c.
Page 22
The note discusses the transmission line model and wave equations. It starts by defining the forward and backward waves as \( e^{-jkz} \) and \( e^{jkz} \) respectively. The phase condition is given as \( \Delta \phi = -2kz = 2k\pi \), leading to a wave number \( k = \frac{\pi}{z} \).
The note then delves into the wave equation for the electric field \( E \) and magnetic field \( H \):
$$ \frac{\partial^2 E}{\partial z^2} + k^2 E = 0 $$
$$ \frac{\partial^2 H}{\partial z^2} + k^2 H = 0 $$
The solution is expressed as:
$$ E = E_T e^{jkz} + E_{T+} e^{-jkz} $$
$$ H = H_T e^{jkz} + H_{T+} e^{-jkz} $$
The note introduces the concept of voltage \( V \) and current \( I \) as:
$$ V = V_T e^{jkz} + V_{T+} e^{-jkz} $$
$$ I = I_T e^{jkz} + I_{T+} e^{-jkz} $$
The impedance \( Z \) is defined as:
$$ Z = \frac{V}{I} = \frac{V_T}{I_T} = \frac{V_{T+}}{I_{T+}} $$
The reflection coefficient \( \Gamma \) is given by:
$$ \Gamma = \frac{V_{T+} - V_T}{V_{T+} + V_T} = \frac{I_T - I_{T+}}{I_T + I_{T+}} $$
The note also discusses the power ratio \( p \):
$$ p = \frac{V_{max}}{V_{min}} = \frac{1 + \Gamma}{1 - \Gamma} $$
The minimum phase angle \( \phi \) is defined as:
$$ \phi = \frac{\pi}{2kz} $$
The reflection coefficient \( \Gamma \) is related to the impedance \( Z \) and admittance \( Y \) as:
$$ \Gamma = \frac{Z - Z_0}{Z + Z_0} = \frac{Y - Y_0}{Y + Y_0} $$
The note concludes with the reflection and transmission coefficients for the wave:
$$ \Gamma = \frac{V_{T+} - V_T}{V_{T+} + V_T} = \frac{I_T - I_{T+}}{I_T + I_{T+}} $$
$$ \Gamma = \frac{Z - Z_0}{Z + Z_0} = \frac{Y - Y_0}{Y + Y_0} $$
Page 23
Here's the extracted text and formulas from the handwritten note, with placeholders for the diagrams:
---
**2. Pure Reflection State**
1) End Short Circuit:
$$\overline{Z_F} \triangleq \infty / \overline{Y_F} \triangleq 0 \Rightarrow \Gamma_F = +1$$
$$V(z) = 2V_0 + \cos(k_2z) \quad |V(z)| = 2|V_0| |\cos(k_2z)|$$
$$I(z) = 2j\frac{V_0}{Z_0} \sin(k_2z) \quad |I(z)| = 2\left|\frac{V_0}{Z_0}\right| |\sin(k_2z)|$$
$$\Gamma(z) = +e^{-j2k_2z}$$
$$\overline{Z_1}(z) = -j\cot(k_2z) \quad \overline{y_1}(z) = j\tan(k_2z)$$
2) End Open Circuit:
$$\overline{Z_F} \triangleq 0 / \overline{Y_F} \triangleq \infty \Rightarrow \Gamma_F = -1$$
$$V(z) = j2V_0 + \sin(k_2z) \quad |V(z)| = 2|V_0| |\sin(k_2z)|$$
$$I(z) = 2j\frac{V_0}{Z_0} \cos(k_2z) \quad |I(z)| = 2\left|\frac{V_0}{Z_0}\right| |\cos(k_2z)|$$
$$\Gamma(z) = -e^{-j2k_2z}$$
$$\overline{Z_1}(z) = j\tan(k_2z) \quad \overline{y_1}(z) = -j\cot(k_2z)$$
3) End Impedance:
$$\overline{Z_F} \triangleq jx \quad \overline{y_F} \triangleq jb \quad |\Gamma_F| = 1 \quad (\Gamma_F = e^{j\phi_F})$$
$$V(z) = 2V_0 + e^{j\phi_F} \cos(k_2z - \frac{\phi_F}{2}) \quad |V(z)| = 2|V_0| |\cos(k_2z - \frac{\phi_F}{2})|$$
$$I(z) = 2j\frac{V_0}{Z_0} e^{j\frac{\phi_F}{2}} \sin(k_2z - \frac{\phi_F}{2}) \quad |I(z)| = 2\left|\frac{V_0}{Z_0}\right| |\sin(k_2z - \frac{\phi_F}{2})|$$
$$\Gamma(z) = e^{j(\phi_F - 2k_2z)}$$
$$\overline{Z_1}(z) = -j\cot(k_2z - \frac{\phi_F}{2}) \quad \overline{y_1}(z) = j\tan(k_2z - \frac{\phi_F}{2})$$
**3. Mixed Reflection State**
$$V(z) = V_0(1 + \Gamma_F e^{-j2k_2z}) \quad |V(z)| = |V_0| (1 + |\Gamma_F| e^{j(\phi_F - 2k_2z)})$$
$$I(z) = \frac{V_0}{Z_0} (1 - \Gamma_F e^{-j2k_2z}) \quad |I(z)| = \left|\frac{V_0}{Z_0}\right| (1 - |\Gamma_F| e^{j(\phi_F - 2k_2z)})$$
$$\Gamma(z) = |\Gamma_F| e^{j(\phi_F - 2k_2z)}$$
$$\overline{Z_1}(z) = \frac{1 - \Gamma_F e^{-j2k_2z}}{1 + \Gamma_F e^{-j2k_2z}} \quad \overline{y_1}(z) = \frac{1 - \Gamma_F e^{-j2k_2z}}{1 + \Gamma_F e^{-j2k_2z}}$$
---
Page 24
**1. Basic Parameters:**
- **Radiation Pattern:** Far field region has E and H components. The power density:
$$ S = \frac{1}{2} (\vec{E} \times \vec{H}^*) = \frac{1}{r} \frac{1}{2\eta} (|E_{\theta}|^2 + |E_{\phi}|^2) $$
$$ E_{\theta} = \frac{f_{\theta}(\theta, \phi)}{r} e^{-jkr}, E_{\phi} = \frac{f_{\phi}(\theta, \phi)}{r} e^{-jkr}, \vec{H} = \frac{1}{r} \hat{\phi} \times \vec{E} $$
$$ \therefore S = \frac{1}{2\eta r^2} (|f_{\theta}(\theta, \phi)|^2 + |f_{\phi}(\theta, \phi)|^2) $$
$$ F(\theta, \phi) \triangleq r^2 S = \frac{1}{2\eta} (|f_{\theta}(\theta, \phi)|^2 + |f_{\phi}(\theta, \phi)|^2) $$
$$ F_{\mathrm{m}}(\theta, \phi) \triangleq F(\theta, \phi) / F_{\mathrm{max}}(\theta, \phi) $$
- **E Plane Pattern:** E field in plane F, e.g. φ = const for a disk.
- **H Plane Pattern:** H field in plane F, e.g. θ = 90° for a disk.
**2. Directional Coefficient (Radiation Power Density):**
$$ D(\theta, \phi) \triangleq \frac{S_r(\theta, \phi)}{P_r / 4\pi r^2} $$
**3. Antenna Gain (Input Power is the same):**
$$ G(\theta, \phi) \triangleq \frac{S_r(\theta, \phi)}{P_{\mathrm{in}} / 4\pi r^2} $$
**4. Polarization:**
- Linear Polarization: Parallel polarization (parallel to the plane), Vertical polarization (perpendicular to the plane).
- Circular Polarization: Right-hand circular polarization (right-hand rule), Left-hand circular polarization (left-hand rule).
- Elliptical Polarization: The ratio of the major axis to the minor axis of the ellipse.
**5. Input Impedance:**
$$ Z_{\mathrm{in}} = \text{standing wave ratio} / \text{incident current} \text{ (on the surface)} $$
**6. Radiation Resistance:**
$$ R_{\mathrm{rad}} = \frac{2P_r}{I^2} $$
**7. Bandwidth:**
The frequency range that meets the radiation resistance and gain requirements.
Page 25
3. Point Source (Z = 2.0 e^(jπx))
Near Field: S is complex, no radiation, no field.
Far Field: S is real, radiated field, spherical wave.
Hφ ≈ $$\frac{2\phi}{4\pi} e^{-jk\phi} \frac{jk}{r} \sin\theta \approx E_0 / \eta$$
E0 ≈ $$\frac{2\phi}{4\pi} e^{-jk\phi} j\frac{4\pi}{k} \sin\theta$$
S_r = $$\frac{1}{2} (E_0 \times H_\phi^*) \cdot \hat{r} = \frac{\eta}{8} \left(\frac{2\phi}{\lambda}\right)^2 \frac{\sin^2\theta}{r^2}$$
P_r = $$\phi_s S_r ds = 40\pi^2 \left(\frac{2\phi}{\lambda}\right)^2$$
R_r = $$2P_r / Z^2 = 80\pi^2 \left(\frac{\lambda}{\phi}\right)^2$$
f_n(θ) = sinθ, F_n(θ) = sin^2θ
f_n(θ) = 1/2 => |θ2 - θ1| = 90°: half-power angle.
D(θ,φ) = $$\frac{S_r}{P_r / 4\pi r^2} = \frac{3}{2} \sin^2\theta$$ θ = π/2 1.5 = 1.76 dB.
4. Wire Antenna
Far Field:
α = j $$\frac{Id^3}{4\pi r} e^{-jk\phi} \frac{1}{r} \sin\theta = dE_0 / \eta$$
dE0 = $$\frac{Id^3}{4\pi r} e^{-jk\phi} j\frac{4\pi}{k} \sin\theta$$
① Symmetric Wire:
$$\begin{cases} I(x) = 2.0 \sin k(\frac{l}{2} - z) & 0 \leq z \leq \frac{l}{2} \\ I(x') = I_0 \sin k(\frac{l}{2} + z) & -\frac{l}{2} \leq z' \leq 0 \end{cases}$$
R ≈ r
Hφ = j $$\frac{2\phi}{2\pi r} \cdot \frac{\cos(\frac{k\phi}{2} \cos\theta) - \cos\frac{k\phi}{2}}{\sin\theta} = E_0 / \eta$$
E0 = j $$\frac{2\phi}{2\pi r} \cdot \frac{\cos(\frac{k\phi}{2} \cos\theta) - \cos\frac{k\phi}{2}}{\sin\theta}$$
S_r ≈ $$\eta \frac{2\phi^2}{8\pi^2 r^2} \left[\frac{\cos(\frac{k\phi}{2} \cos\theta) - \cos\frac{k\phi}{2}}{\sin\theta}\right]^2$$
l = λ/2: P_r = 36.54 Z^2
R_r = 73 Ω = Zin.
f_n(θ) = $$\frac{\cos(\frac{\pi}{2} \cos\theta)}{\sin\theta}$$, F_n(θ) = $$\frac{f_n(0)}{(1 - \cos\frac{\pi}{2})^2}$$
f_n(θ) = 1/2 => |θ2 - θ1| = 78°: half-power angle.
D(θ,φ) = $$\frac{80}{\pi^2}$$ 1.64 = 2.15 dB.
l = λ: R_r = 200 Ω, f = λ/2: P_r = 106 Ω.
Page 26
2. Folded dipole
$$\rho_{r} \approx 2 \times 73 \Omega$$
$$Z_{in} \approx 4 \times 73 \Omega$$
3. Monopole antenna
$$D = 2D_{folded}$$
$$\lambda = \frac{\lambda}{4}$$
4. Inverted L antenna
$$\Delta R_{end}$$
5. Dipole antenna - Yagi-Uda
6. Planar antenna
Far field: Conductors/ferromagnetic materials + image principle.
$$\vec{J}_{ms} = -\hat{n} \times \vec{E}$$
$$\vec{J}_{es} = \hat{n} \times \vec{H}$$
1. Guided wave. ($\vec{E}_{y} = \hat{y} E_{0}$)
$$\vec{J}_{ms} = \hat{x} \vec{J}_{m} = \hat{x} \cdot 2 \vec{E}_{0}$$
$$\vec{H}_{mo} = -j \omega \epsilon_{0} \mu_{0} \vec{E}_{0} \cdot ab \sin \left(\frac{\pi a}{2} \cos \phi \right) \sin \left(\frac{\pi b}{2} \cos \phi \right)$$
$$\vec{H}_{mp} = -j \omega \epsilon_{0} \mu_{0} \vec{E}_{0} \cdot ab \sin \left(\frac{\pi a}{2} \cos \phi \right) \sin \left(\frac{\pi b}{2} \cos \phi \right)$$
$$\vec{H}_{mp} = -j \omega \epsilon_{0} \mu_{0} \vec{E}_{0} \cdot ab \sin \left(\frac{\pi a}{2} \cos \phi \right) \sin \left(\frac{\pi b}{2} \cos \phi \right)$$
Page 27
Here's the extracted text and formulas from the handwritten note, with placeholders for the diagrams:
---
**φ = 90°:**
$$ f_{n,E} = S a\left(\frac{k b}{2} \sin \phi\right) \triangleq \frac{1}{\sqrt{2}} \quad 2 \theta_{0.5,E} \approx 51^{\circ} \cdot \frac{\lambda}{5} $$
**φ = 0°:**
$$ f_{n,H} = S a\left(\frac{k a}{2} \cos \phi\right) \triangleq \frac{1}{\sqrt{2}} \quad 2 \theta_{0.5,H} \approx 51^{\circ} \cdot \frac{\lambda}{a} $$
---
**② Rectangular Waveguide (Ez = Eo sin(π/αx))**
$$ 2 \theta_{0.5,E} = 68^{\circ} \cdot \frac{\lambda}{6} $$
$$ 2 \theta_{0.5,H} = 68^{\circ} \cdot \frac{\lambda}{a} $$
---
**③ Parabolic Reflector**
---
**④ Cardioid Array: Using "polarization" to achieve beamwidth reduction**
---
**6. Array**
---
**① Array**
1) Binary:
$$ E_{0} = j \frac{k n 2 d}{4 \pi} \frac{e^{j k r}}{r} \sin \phi \cdot 2 \cos \frac{k d \cos \phi + \beta}{2} $$
$$ = j \frac{k n 2 d}{4 \pi} \frac{e^{j k r}}{r} f_{e}(\theta, \phi) - f_{a}(\theta, \phi) $$
2) N-element:
$$ f_{n} = \sin \frac{N \beta}{2} / N \sin \frac{\beta}{2} \quad N \text{ is an integer, } \beta = k d \cos \phi + \beta $$
$$ \theta_{\max} = \cos^{-1} \left( \frac{\beta}{k d} \right), \phi = 0 $$
$$ \theta_{0} = \cos^{-1} \left( \frac{2 p \pi}{N k d} - \frac{\beta}{k d} \right), \phi = \frac{2 p \pi}{N}, p = \pm 1, \pm 2, \ldots $$
$$ \theta_{\max, \phi} = \cos^{-1} \left( \frac{2 p + \frac{1}{2} \pi}{N k d} - \frac{\beta}{k d} \right), \phi = \frac{2 p + \frac{1}{2} \pi}{2 N}, p = (1, -2), (2, -3), (3, -1), \ldots $$
---
**3) Microwave Array: Two-element array**
$$ f_{E, a} = S a\left(\frac{k b}{2} \sin \phi\right) \cdot 2 \cos \left( \frac{\beta}{2} \cos \phi \right) $$
$$ f_{H, a} = S a\left(\frac{k a}{2} \cos \phi\right) \cdot 2 \cos \left( \frac{\beta}{2} \cos \phi \right) $$
---
Page 28
$$ Z_{in} = \frac{R_{r}}{2} $$
$$ R_{r} \approx \left\{ \begin{array}{ll} 120 \frac{\lambda}{W} & W \geq 2\lambda \\ R_{0} \left(\frac{\lambda}{W}\right)^2 & W < 0.35\lambda \\ \left[\frac{W}{120\lambda} - \frac{1}{60\pi}\right]^{-1} & 0.25\lambda \leq W < 2\lambda \end{array} \right. $$
4) Waveguide slot antenna: cutting the same direction current. Top figure:
2) Face array: \( f_{a} = f_{ax} \cdot f_{ay} \)
3) Body array: \( f_{a} = f_{ax} \cdot f_{ay} \cdot f_{az} \)
Review Outline
1. Transmission Line
1. Transmission line theory formulas:
$$ \Gamma = \frac{Z_{s} - Z_{c}}{Z_{s} + Z_{c}} $$
$$ Z_{s} = \frac{1 + \Gamma}{1 - \Gamma} \quad (\Gamma = \frac{1}{2}) $$
$$ Z_{c} = \frac{1}{\Gamma} $$
$$ P = \frac{4\pi I_{0}^{2}}{1 - |\Gamma|^{2}} \quad (\Gamma = \frac{V_{max}}{V_{min}}) $$
$$ Z = Z_{in} / Z_{c} $$
$$ \Gamma_{F} = \frac{2\Gamma - 1}{2\Gamma + 1} $$
$$ \Gamma_{i} = \frac{1 - \Gamma}{1 + \Gamma} \quad (\Gamma = \frac{1}{2}) $$
$$ Y_{c} $$
$$ k = \frac{1}{\rho} $$
$$ \bar{y} = \frac{1}{\bar{z}} $$
2. Smith chart construction, chart rules. Mark the meaning of each line on the chart, and solve the problem.
Resistance circle:
$$ \Gamma = |\Gamma_{F}| e^{j(\phi_{F} - 2k\pi)} $$
$$ \Gamma = -1 $$
$$ r < 1 $$
$$ r > 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = \infty $$
$$ Z = Z_{0} + Z_{-} = 0 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$ \Gamma = -1 $$
$$ r = 1 $$
$$ \Gamma = 1 $$
$$
Page 29
1. Find the area of the double line transformer (Example 2.9 on page 49).
2. Diagram 1: Capacitive and inductive components.
3. Diagram 2: Capacitive and inductive components with a short circuit.
4. Diagram 3: Capacitive and inductive components with a short circuit and a voltage distribution line.
5. Diagram 4: Capacitive and inductive components with a voltage distribution line and a short circuit.
6. Diagram 5: Capacitive and inductive components with a voltage distribution line and a short circuit, and a ZF transformer.
7. Diagram 6: Capacitive and inductive components with a voltage distribution line and a short circuit, and a ZF transformer, with a ZF transformer at 0.3-j0.5.
Page 30
3. Impedance Example
P48. Example 2.8 (Delta Impedance).
$$ Z_{c} = \frac{1 + \Gamma_{F}}{1 - \Gamma_{F}} = \frac{1 + \Gamma_{F} e^{-j2k_{a}z}}{1 - \Gamma_{F} e^{j2k_{a}z}} $$
$$ = \frac{1 + \Gamma_{F} e^{-j\pi}}{1 - \Gamma_{F} e^{-j\pi}} = \frac{1 - \Gamma_{F}}{1 + \Gamma_{F}} = \frac{1}{2\Gamma_{F}} $$
P76. 2.10.
$$ Z_{F} = \frac{20 - j30}{30} = 0.67 - j1 $$
4. Voltage Distribution
P46. Example 2.6. Before.
$$ \Gamma_{F} = \frac{4 - 1}{4 + 1} = \frac{2 - 1}{2 + 1} = \frac{1}{3} = \frac{V_{0-}}{V_{0+}} $$
$$ Z = 0 \text{ when } |V| = |V_{0+}|(1 + \frac{1}{3}) $$
Page 31
(b) $$\Gamma_F = \frac{2-1}{2+1} = \frac{1}{3}$$ $$|V| = |V_0| + \frac{1}{3} e^{-j\frac{2\pi}{3}}$$
$$Z_{\text{ref}}' = \frac{1-\Gamma_F}{1+\Gamma_F} = \frac{1-\frac{1}{3} e^{-j\frac{2\pi}{3}}}{1+\frac{1}{3} e^{-j\frac{2\pi}{3}}} = \frac{1-\frac{1}{3}}{1+\frac{1}{3}} = 2Z_c$$
$$\therefore Z_{\text{ref}} = 2Z_c // 2Z_c = Z_c \therefore \Gamma_{\text{ref}} = 0$$
(c) $$\Gamma_{F_1} = \frac{1}{3}, \Gamma_{F_2} = \frac{1}{3}$$
$$Z_{\text{ref}} = 2Z_c // \frac{1}{2}Z_c = \frac{2}{3}Z_c$$
$$\therefore \Gamma_{\text{ref}} = \frac{1}{1+\frac{2}{3}} = -\frac{3}{7}$$
$$\therefore |V| = |V_0| + \frac{3}{7} e^{-j\frac{2\pi}{3}}$$
5. Incident voltage, reflected voltage, total voltage, reflection coefficient concept.
$$V = V_+ + V_-$$
$$\Gamma = \frac{V_-}{V_+}$$
$$\overline{Z}_{PA} = 0.5, \overline{Z}_{PB} = 2, \therefore \overline{Z}_{\text{ref}} = 2//2 = 1$$
$$\therefore \overline{Z}_{FA} = 1, \overline{Z}_{FB} = 50\Omega$$
$$\therefore \Gamma_C = 0, V_B' = V_B e^{-j\frac{2\pi}{3}} = -jV_B, P_{FB} = \frac{V_B^2}{2R_{FB}}$$
$$\& \overline{Z}_{FA} = 2, \therefore \Gamma_B = \frac{2-1}{2+1} = \frac{1}{3}$$
$$\therefore V_- = \frac{3}{4}V_B, V_+ = \frac{1}{4}V_B$$
$$\therefore V_A = V_- e^{-j\frac{2\pi}{3}} + V_+ e^{j\frac{2\pi}{3}} = (-j\frac{3}{4} + j\frac{1}{4})V_B$$
$$= -\frac{1}{2}V_B = -\frac{1}{2}V_B^*, P_{FA} = \frac{V_B^2}{8R_{FA}}$$
Directivity and transience of the reflection coefficient!
Page 32
Waveguides
# 1. Solution Methods for Waveguides, Cylindrical Waveguides, and Coaxial Cables
**Circular Waveguide:**
- TE mode:
$$\left\{\begin{array}{l}
\nabla^2 H_z(x, y) + k_0^2 H_z(x, y) = 0 \\
\left.\frac{\partial H_z}{\partial n}\right|_{z=0} = 0
\end{array}\right.$$
$$\eta_{TE} = \frac{\omega \mu}{k_0^2}$$
- TM mode:
$$\left\{\begin{array}{l}
\nabla^2 E_z(x, y) + k_0^2 E_z(x, y) = 0 \\
\left.\frac{\partial E_z}{\partial n}\right|_{z=0} = 0
\end{array}\right.$$
$$\eta_{TM} = \frac{k_0^2}{\omega \mu}$$
**Rectangular TE mode:**
$$\left\{\begin{array}{l}
\frac{\partial^2}{\partial x^2} H_z + \frac{\partial^2}{\partial y^2} H_z + k_0^2 H_z = 0 \\
\left.\frac{\partial H_z}{\partial x}\right|_{x=0, a} = 0, \left.\frac{\partial H_z}{\partial y}\right|_{y=0, b} = 0
\end{array}\right.$$
$$\therefore H_z(x, y) = H_{mn} \cos\left(\frac{m\pi}{a} x\right) \cos\left(\frac{n\pi}{b} y\right)$$
$$H_x(x, y) = \frac{j k_0}{k_0^2} \left(\frac{m\pi}{a}\right) H_{mn} \sin\left(\frac{m\pi}{a} x\right) \cos\left(\frac{n\pi}{b} y\right)$$
$$H_y(x, y) = \frac{j k_0}{k_0^2} \left(\frac{n\pi}{b}\right) H_{mn} \cos\left(\frac{m\pi}{a} x\right) \sin\left(\frac{n\pi}{b} y\right)$$
$$E_x(x, y) = \eta_{TE} H_y(x, y)$$
$$E_y(x, y) = -\eta_{TE} H_x(x, y)$$
**Rectangular TM mode:**
$$\left\{\begin{array}{l}
\frac{\partial^2}{\partial x^2} E_z + \frac{\partial^2}{\partial y^2} E_z + k_0^2 E_z = 0 \\
\left.\frac{\partial E_z}{\partial x}\right|_{x=0, a} = 0, \left.\frac{\partial E_z}{\partial y}\right|_{y=0, b} = 0
\end{array}\right.$$
$$\therefore E_z(x, y) = E_{mn} \sin\left(\frac{m\pi}{a} x\right) \sin\left(\frac{n\pi}{b} y\right)$$
$$E_x(x, y) = -\frac{j k_0}{k_0^2} \left(\frac{m\pi}{a}\right) E_{mn} \cos\left(\frac{m\pi}{a} x\right) \sin\left(\frac{n\pi}{b} y\right)$$
$$E_y(x, y) = -\frac{j k_0}{k_0^2} \left(\frac{n\pi}{b}\right) E_{mn} \sin\left(\frac{m\pi}{a} x\right) \cos\left(\frac{n\pi}{b} y\right)$$
$$H_x(x, y) = -\frac{1}{\eta_{TM}} E_y(x, y)$$
$$H_y(x, y) = \frac{1}{\eta_{TM}} E_x(x, y)$$
**Circular TE mode:**
$$\left\{\begin{array}{l}
\frac{1}{r} \frac{\partial}{\partial r} \left(r \frac{\partial H_z}{\partial r}\right) + \frac{1}{r^2} \frac{\partial^2 H_z}{\partial \varphi^2} + k_0^2 H_z = 0
\end{array}\right.$$
$$H_z(r, \varphi) = H_{mn} J_n(k_0 r) \cos(n\varphi)$$
$$H_r(r, \varphi) = -\frac{j k_0 n}{k_0^2 r} H_{mn} J_n'(k_0 r) \cos(n\varphi)$$
$$H_\varphi(r, \varphi) = \frac{j k_0 n}{k_0^2 r} H_{mn} J_n(k_0 r) \sin(n\varphi)$$
$$E_r(r, \varphi) = \eta_{TE} H_\varphi(r, \varphi)$$
$$E_\varphi(r, \varphi) = -\eta_{TE} H_r(r, \varphi)$$
Page 33
The notebook page contains a detailed set of equations and explanations related to electromagnetic wave propagation in coaxial cables and waveguides. Here's a breakdown of the content:
---
**Circular TM Mode:**
$$\left\{\begin{array}{l}
\frac{1}{r} \frac{\partial}{\partial r} \left( r \frac{\partial E_{z}}{\partial r} \right) + \frac{1}{r^{2}} \frac{\partial^{2} E_{z}}{\partial \varphi^{2}} + k_{c}^{2} E_{z} = 0 \\
E_{z} \mid_{r=R}=0.
\end{array}\right.$$
$$E_{z}(r,\varphi) = E_{m} J_{n}(k_{c} r) \cos(n\varphi)$$
$$E_{r}(r,\varphi) = -\frac{j k_{c}^{2} n}{k_{c} r} E_{m} J_{n}^{\prime}(k_{c} r) \cos(n\varphi)$$
$$E_{\varphi}(r,\varphi) = \frac{j k_{c}^{2} n}{k_{c} r} E_{m} J_{n}(k_{c} r) \sin(n\varphi)$$
$$H_{r}(r,\varphi) = -\frac{1}{\eta_{TM}} E_{\varphi}(r,\varphi)$$
$$H_{\varphi}(r,\varphi) = \frac{1}{\eta_{TM}} E_{r}(r,\varphi).$$
**Coaxial TEM Mode:**
$$\nabla_{T} \cdot \vec{E}(x,y) = 0 \Rightarrow \nabla_{T}^{2} \psi = -\frac{1}{r} \frac{\partial}{\partial r} \left( r \frac{\partial \psi}{\partial r} \right) + \frac{1}{r^{2}} \frac{\partial^{2} \psi}{\partial \varphi^{2}} = 0.$$
$$\psi = \frac{V}{\ln(a/b)} \ln r.$$
$$\therefore \vec{E}_{T}(x,y) = -\frac{\partial \psi}{\partial r} \hat{r} = -\frac{V}{r \ln(a/b)} \hat{r}$$
$$\vec{H}_{T}(x,y) = \frac{1}{\eta_{TEM}} \hat{z} \times \vec{E}_{T}(x,y)$$
$$\eta_{TEM} = \frac{\omega \mu}{k} = \sqrt{\frac{\mu}{\epsilon}}.$$
**Coaxial TE Mode:**
$$\left\{\begin{array}{l}
\frac{1}{r} \frac{\partial}{\partial r} \left( r \frac{\partial H_{z}}{\partial r} \right) + \frac{1}{r^{2}} \frac{\partial^{2} H_{z}}{\partial \varphi^{2}} + k_{c}^{2} H_{z} = 0 \\
\frac{\partial H_{z}}{\partial r} \mid_{r=a} = \frac{\partial H_{z}}{\partial r} \mid_{r=b} = 0.
\end{array}\right.$$
**Coaxial TM Mode:**
$$\left\{\begin{array}{l}
\frac{1}{r} \frac{\partial}{\partial r} \left( r \frac{\partial E_{z}}{\partial r} \right) + \frac{1}{r^{2}} \frac{\partial^{2} E_{z}}{\partial \varphi^{2}} + k_{c}^{2} E_{z} = 0 \\
E_{z} \mid_{r=a} = E_{z} \mid_{r=b} = 0.
\end{array}\right.$$
---
**Question 2:**
*What mode (or modes) does each of the above transmission lines and waveguides support? How does the electromagnetic field distribution look for each mode? How can we ensure single-mode transmission?*
*Solution:*
*TE10:*
$$\lambda_{c} = 2 \sqrt{\left(\frac{m}{a}\right)^{2} + \left(\frac{n}{b}\right)^{2}}, \quad m=1, n=0 \sim m=2, n=0.$$
*The single-mode TE10 works when*
$$a < \lambda_{c} < 2a, \quad \frac{\lambda_{c}}{2} < a < \lambda_{c}.$$
*General working frequency range*
$$1.05a \leq \lambda_{c} \leq 0.8 \times 2a.$$
Page 34
No.
Date
1. TE01 mode and TM01 mode
Circle:
TE11 mode:
$$\lambda_c = \frac{2\pi a}{V_{ni}}$$
$$n=1, i=1 \rightarrow TE11$$
$$\lambda_c = \frac{2\pi a}{V_{ni}}$$
$$n=0, i=1 \rightarrow TM10$$
The single mode working area for TE11 mode is:
$$\frac{\lambda_c}{3.41} < a < \frac{\lambda_c}{2.61}$$
$$a \approx \frac{2}{3}$$
Coaxial line:
TEM mode:
$$\lambda_c = \pi(a+b)$$
The single mode working area for TEM mode is:
$$\lambda_c \geq \pi(a+b) \Rightarrow \lambda_c \geq 1.1\pi(a+b)$$
Waveguide:
Quasi-TEM mode:
$$\lambda_g = \frac{\lambda_0}{\sqrt{\epsilon_r}}$$
3. TE01 mode internal surface current distribution. Which slots will cut these surface currents and cause radiation?
Page 35
The page contains handwritten notes and diagrams related to electromagnetic wave modes in rectangular and circular waveguides. Here's a breakdown:
**Rectangular Waveguide Diagrams:**
- **TEmn:** Represents the electric field component in the y-direction, with arrows indicating the direction of the field. The subscript 'm' and 'n' denote the number of half-periods of the field in the x and y directions, respectively.
- **TMmn:** Represents the magnetic field component in the x-direction, with arrows indicating the direction of the field. The subscript 'm' and 'n' denote the number of half-periods of the field in the x and y directions, respectively.
**Circular Waveguide Diagrams:**
- **TEmi:** Represents the electric field component in the y-direction, with arrows indicating the direction of the field. The subscript 'm' and 'n' denote the number of half-periods of the field in the x and y directions, respectively.
- **TMmi:** Represents the magnetic field component in the x-direction, with arrows indicating the direction of the field. The subscript 'm' and 'n' denote the number of half-periods of the field in the x and y directions, respectively.
The notes also mention that the field components are periodic and that the field values are zero at the boundaries of the waveguide. The diagrams illustrate the field patterns in both rectangular and circular waveguides, with arrows indicating the direction of the field components.
Page 36
5. Impedance Matching Methods and Rules.
Excitation Methods: Electric Field Excitation, Magnetic Field Excitation, Electromagnetic Excitation
Equivalent J_e Equivalent J_m Equivalent J_e J_m
Excitation Rule: ∫(E·J_e + H·J_m) dV ≠ 0 Excitation (field and source interaction)
(Condition) Voltage frequency and current zero condition! ∫ = 0 Not excitable (field and source no interaction).
III. Microwave Network.
1. S-parameters Definition, Properties, Physical Meaning?
Definition: S_ij = b_i / a_j | a_k ≠ i = 0; According to this, S_ii = Γ_i
[b_1] = [S_11 ... S_1n] [a_1]
[b_n] = [S_n1 ... S_nn] [a_n]
a = I + √2c = V_+ / √2c.
b = -I - √2c = V_- / √2c
Properties: N-ports:
Symmetry: S_ij = S_ji, [S] = [S]^T.
Non-reciprocity: [S]^H [S] = I, ∴ Symmetric [S] [S]^H [S] = I
2. Endports:
Symmetry: S_12 = S_21 (unknown)
Non-reciprocity: |S_12| = |S_21|, |S_11| = |S_22|, |S_11|^2 + |S_22|^2 = 1, |S_12|^2 + |S_22|^2 = 1 (unknown).
(Values: unknown)
(Magnitudes: unknown)
Physical Meaning: S_ii: Port connected to the source, other port connected to the load or load, i-port reflection coefficient.
Page 37
2. Reference plane transformation of [S]
$$ S_{11}' = \frac{b_1 e^{-j\theta_1}}{a_1 e^{j\theta_1}} |_{a_2=0} = S_{11} e^{-j2\theta_1} $$
$$ S_{22}' = \frac{b_2 e^{-j\theta_2}}{a_2 e^{j\theta_2}} |_{a_1=0} = S_{22} e^{-j2\theta_2} $$
$$ S_{21}' = \frac{b_2 e^{-j\theta_2}}{a_1 e^{j\theta_1}} |_{a_2=0} = S_{21} e^{-j(\theta_1+\theta_2)} $$
$$ S_{12}' = \frac{b_1 e^{-j\theta_1}}{a_2 e^{j\theta_2}} |_{a_1=0} = S_{12} e^{-j(\theta_1+\theta_2)} $$
$$ \therefore [S'] = \begin{bmatrix} S_{11} e^{-j2\theta_1} & S_{12} e^{-j(\theta_1+\theta_2)} \\ S_{21} e^{-j(\theta_1+\theta_2)} & S_{22} e^{-j2\theta_2} \end{bmatrix} = \begin{bmatrix} e^{-j\theta_1} & 0 \\ 0 & e^{-j\theta_2} \end{bmatrix} \begin{bmatrix} S_{11} & S_{12} \\ S_{21} & S_{22} \end{bmatrix} \begin{bmatrix} e^{-j\theta_1} & 0 \\ 0 & e^{-j\theta_2} \end{bmatrix} $$
Note: [S'] = [P] [S] [P] , [P] = diag{e^{-j\theta_i}}. i=1,...,n.
3. Time-domain network [S] solution method: open circuit → S1; short circuit → S2.
Page 187 Example 4.5.
$$ S_{21} = S_{11} = \frac{S_1 + S_2}{2} $$
$$ S_{12} = S_{21} = \frac{S_1 - S_2}{2} $$
$$ \frac{(Z_c) Y}{(Z_c)} \Rightarrow \frac{(Z_c) Y}{\frac{1}{2} (Z_c)} $$
Short:
$$ S_2 = -1 $$
Open:
$$ S_1 = \frac{Y/2 \cdot Z_c + 1}{Y/2 \cdot Z_c + 1} = \frac{2Yc - Y}{2Yc + Y} $$
$$ \therefore S_{11} = S_{22} = \frac{S_1 + S_2}{2} = \frac{1}{2} \cdot \frac{-2Y}{2Yc + Y} = -\frac{Y}{2Yc + Y} $$
$$ S_{12} = S_{21} = \frac{S_1 - S_2}{2} = \frac{1}{2} \cdot \frac{4Yc}{2Yc + Y} = \frac{2Yc}{2Yc + Y} $$
$$ S_{11} = \frac{b_1}{a_1} |_{a_2=0} = \Gamma_1 = \frac{1 - Y_1}{1 + Y_1} = \frac{Y_c - (R + Y_c)}{Y_c + (R + Y_c)} = -\frac{Y}{R + 2Y_c} $$
$$ S_{21} = \frac{b_2}{a_1} |_{a_2=0} = \frac{a_1 + a_1 \Gamma_1}{a_1} = 1 + \Gamma_1 = \frac{2Yc}{Y + 2Y_c} $$
Page 38
Lesson Example:
$$\Gamma_{\phi 2} = -e^{-j\kappa_2 \cdot 2 \cdot \frac{\lambda}{8}} = -(-j) = j$$
$$\Gamma_{\phi 1} = e^{-j\kappa_2 \cdot 2 \cdot \frac{\lambda}{8}} = -j$$
$$\Sigma_{\phi 2} = \frac{1 + \Gamma_{\phi 1}}{1 - \Gamma_{\phi 1}} = \frac{1 + j}{1 - j}$$
$$\Sigma_{\phi 1} = \frac{1 + \Gamma_{\phi 2}}{1 - \Gamma_{\phi 2}} = \frac{1 - j}{1 + j}$$
$$\therefore Z_{\phi 2} = \frac{1}{Y_{C2}} - \frac{1 + j}{1 - j}, Z_{\phi 1} = \frac{1}{Y_{C1}} + \frac{1 - j}{1 + j}$$
$$\therefore Y_{\phi} = Y_{C2} \frac{1 + j}{1 + j} + Y_{C1} \frac{1 + j}{1 - j}$$
$$\therefore \Gamma_{\phi} = \frac{1 - Y_{\phi}}{1 + Y_{\phi}} = \frac{Y_{C2} \frac{1 - j}{1 + j} + Y_{C1} \frac{1 + j}{1 - j}}{Y_{C2} \frac{1 - j}{1 + j} + Y_{C1} \frac{1 + j}{1 - j}} = S_1$$
$$\therefore S_{11} = S_{22} = \frac{S_1 + S_2}{2}, S_{12} = S_{21} = \frac{S_1 - S_2}{2}$$
Short Circuit:
$$\Gamma_{\phi 2} = -e^{-j\kappa_2 \cdot 2 \cdot \frac{\lambda}{8}} = -(-j) = j$$
$$\Gamma_{\phi 1} = -j$$
$$\Sigma_{\phi 2} = -j$$
$$\Sigma_{\phi 1} = -j$$
$$\therefore Y_{\phi} = +j(Y_{C1} + Y_{C2})$$
$$\therefore \Gamma_{\phi} = \frac{Y_{C} - Y_{\phi}}{Y_{C} + Y_{\phi}} = \frac{Y_{C} - j(Y_{C1} + Y_{C2})}{Y_{C} + j(Y_{C1} + Y_{C2})} = S_1$$
$$\therefore S_{11} = S_{22} = \frac{S_1 + S_2}{2}, S_{12} = S_{21} = \frac{S_1 - S_2}{2}$$
Open Circuit:
$$\Gamma_{\phi 2} = e^{-j\kappa_2 \cdot 2 \cdot \frac{\lambda}{8}} = -j$$
$$\Gamma_{\phi 1} = -j$$
$$\Sigma_{\phi 2} = -j$$
$$\Sigma_{\phi 1} = -j$$
$$\therefore Y_{\phi} = +j(Y_{C1} + Y_{C2})$$
$$\therefore \Gamma_{\phi} = \frac{Y_{C} - Y_{\phi}}{Y_{C} + Y_{\phi}} = \frac{Y_{C} - j(Y_{C1} + Y_{C2})}{Y_{C} + j(Y_{C1} + Y_{C2})} = S_1$$
$$\therefore S_{11} = S_{22} = \frac{S_1 + S_2}{2}, S_{12} = S_{21} = \frac{S_1 - S_2}{2}$$
$$\Gamma_{\phi 2} = -e^{-j\kappa_2 \cdot 2 \cdot \frac{\lambda}{8}} = -(-j) = j$$
$$\Gamma_{\phi 1} = -j$$
$$\Sigma_{\phi 2} = -j$$
$$\Sigma_{\phi 1} = -j$$
$$\therefore Y_{\phi} = +j(Y_{C1} + Y_{C2})$$
$$\therefore \Gamma_{\phi} = \frac{Y_{C} - Y_{\phi}}{Y_{C} + Y_{\phi}} = \frac{Y_{C} - j(Y_{C1} + Y_{C2})}{Y_{C} + j(Y_{C1} + Y_{C2})} = S_1$$
$$\therefore S_{11} = S_{22} = \frac{S_1 + S_2}{2}, S_{12} = S_{21} = \frac{S_1 - S_2}{2}$$
$$\Gamma_{\phi 2} = e^{-j\kappa_2 \cdot 2 \cdot \frac{\lambda}{8}} = -j$$
$$\Gamma_{\phi 1} = -j$$
$$\Sigma_{\phi 2} = -j$$
$$\Sigma_{\phi 1} = -j$$
$$\therefore Y_{\phi} = +j(Y_{C1} + Y_{C2})$$
$$\therefore \Gamma_{\phi} = \frac{Y_{C} - Y_{\phi}}{Y_{C} + Y_{\phi}} = \frac{Y_{C} - j(Y_{C1} + Y_{C2})}{Y_{C} + j(Y_{C1} + Y_{C2})} = S_1$$
$$\therefore S_{11} = S_{22} = \frac{S_1 + S_2}{2}, S_{12} = S_{21} = \frac{S_1 - S_2}{2}$$
$$\Gamma_{\phi 2} = -e^{-j\kappa_2 \cdot 2 \cdot \frac{\lambda}{8}} = -(-j) = j$$
$$\Gamma_{\phi 1} = -j$$
$$\Sigma_{\phi 2} = -j$$
$$\Sigma_{\phi
Page 39
4. Interconnected matrices [A], [a] [A] ~ [S] transformation.
Interconnected matrix
$$\frac{z_1}{v_1} \rightarrow \begin{bmatrix} [A] \\ \downarrow v_2 \end{bmatrix} \frac{z_2}{v_2}$$
$$\begin{bmatrix} v_1 \\ z_1 \end{bmatrix} = \begin{bmatrix} A & B \\ C & D \end{bmatrix} \begin{bmatrix} v_2 \\ z_2 \end{bmatrix} \quad [A] = \sum_{i=1}^{n} [A_i].$$
Normalized interconnected matrix (normalized matrix).
$$\frac{z_1}{v_1} \rightarrow \begin{bmatrix} \bar{a} \\ \downarrow v_2 \end{bmatrix} \frac{z_2}{v_2} (z_2). \quad \left\{ \begin{array}{l} z = I \cdot \sqrt{2} e \\ v = V / \sqrt{2} e. \end{array} \right.$$
$$\begin{bmatrix} \bar{a} & \bar{b} \\ \bar{c} & \bar{d} \end{bmatrix} = \begin{bmatrix} A \sqrt{\frac{2}{2c_1}} & B \sqrt{\frac{2}{2c_1c_2}} \\ C \sqrt{\frac{2}{2c_1c_2}} & D \sqrt{\frac{2}{2c_1c_2}} \end{bmatrix}.$$
[A] ~ [S] transformation:
$$\begin{aligned}
S_{11} &= \frac{\bar{a} + \bar{b} - \bar{c} - \bar{d}}{\bar{a} + \bar{b} + \bar{c} + \bar{d}} \\
S_{12} &= \frac{2(\bar{a} - \bar{c})}{\bar{a} + \bar{b} + \bar{c} + \bar{d}} \\
S_{21} &= \frac{2(\bar{a} - \bar{c})}{\bar{a} + \bar{b} + \bar{c} + \bar{d}} \\
S_{22} &= \frac{\bar{a} + \bar{b} - \bar{c} + \bar{d}}{\bar{a} + \bar{b} + \bar{c} + \bar{d}} \\
\end{aligned}$$
$$\begin{aligned}
\bar{a} &= \frac{1}{2S_{11}} (1 + S_{11} - S_{22} - |S|) \\
\bar{b} &= \frac{1}{2S_{11}} (1 + S_{11} + S_{22} + |S|) \\
\bar{c} &= \frac{1}{2S_{11}} (1 - S_{11} - S_{22} + |S|) \\
\bar{d} &= \frac{1}{2S_{11}} (1 - S_{11} + S_{22} - |S|).
\end{aligned}$$
Example: Find [A] when the input impedance is matched (S11 = 1 = 0). Use a, b, c, d for convenience.
$$\frac{(z_{c1})}{(z_{c1})} \frac{(z_{c2})}{(z_{c2})} \frac{(z_{c3})}{(z_{c3})}$$
First find [A2]:
$$\begin{aligned}
\bar{a} &= \frac{V_1}{V_2} \mid_{z_2 = 0} = \frac{V_2 \cos k_1 l}{V_2} = \cos k_1 l \\
\bar{b} &= \frac{V_1}{V_2} \mid_{z_2 = 0} = \frac{j2k_1 \sin k_1 l}{\sqrt{2c_1}} = j \sin k_1 l.
\end{aligned}$$
Since symmetric: $\bar{a} = \bar{a}$, $\bar{b} = \bar{c}$.
Find [A3]:
$$\begin{aligned}
\bar{a} &= \frac{V_1}{V_2} \mid_{z_2 = 0} = \frac{V_2 \cos k_1 l}{V_2} = \cos k_1 l \\
\bar{b} &= \frac{V_1}{V_2} \mid_{z_2 = 0} = \frac{j2k_1 \sin k_1 l}{\sqrt{2c_1}} = j \sin k_1 l.
\end{aligned}$$
Since symmetric: $\bar{a} = \bar{a}$, $\bar{b} = \bar{c}$.
$$\therefore [A] = \begin{bmatrix} \sqrt{\frac{2}{2c_1}} & 0 \\ 0 & \sqrt{\frac{2}{2c_1}} \end{bmatrix} = \begin{bmatrix} \sqrt{\frac{2c_1}{2c_1}} & 0 \\ 0 & \sqrt{\frac{2c_1}{2c_1}} \end{bmatrix}.$$
Page 40
$$\therefore [a] = [a_1] \cdot [a_2] \cdot [a_3]$$
$$= \begin{bmatrix}
\frac{z_{c_3}}{z_{c_1}} \cos k_1 & \frac{z_{c_2}}{z_{c_1} z_{c_3}} \sin k_1 \\
\frac{z_{c_2}}{z_{c_1}} \sin k_1 & \frac{z_{c_1}}{z_{c_3}} \cos k_1
\end{bmatrix}$$
Solve for S11:
$$S_{11} = \frac{\bar{a} + \bar{b} - \bar{c} - \bar{d}}{\bar{a} + \bar{b} + \bar{c} + \bar{d}} = \frac{1}{K} \left[ (\sqrt{\frac{z_{c_3}}{z_{c_1}}} - \sqrt{\frac{z_{c_1}}{z_{c_3}}}) \cos k_1 + j (\frac{z_{c_2}}{\sqrt{z_{c_1} z_{c_3}}} - \frac{\sqrt{z_{c_1} z_{c_3}}}{z_{c_2}}) \sin k_1 \right]$$
(K ≠ 0).
$$\left\{
\begin{array}{ll}
z_{c_1} = z_{c_2} = z_{c_3} & S_{11} = 0 \quad \text{Uniform Line} \\
z_{c_1} = z_{c_3}, l = \frac{\lambda}{4} & S_{11} = 0 \quad \text{Quarter-Wave Transformer} \\
z_{c_2} = \sqrt{z_{c_1} z_{c_3}}, l = \frac{\lambda}{4} & S_{11} = 0 \quad \text{Quarter-Wave Transformer}
\end{array}
\right.$$
Antenna
1. **Antenna Pattern**: Main Beam, Side Lobe, Tail, Half Power Angle, Main Beam Half Angle.
$$f_n(\theta, \phi)$$
2. **Antenna Directivity Coefficient D and Gain G**: What are they? What is the difference between them?
Directivity Coefficient: $$D_n(\theta, \phi) = \left| \frac{S_{\mathrm{r}, \max}(\theta, \phi)}{P_r / 4 \pi r^2} \right|$$
Gain: $$G_n(\theta, \phi) = \left| \frac{S_{\mathrm{r}, \max}(\theta, \phi)}{P_r / 4 \pi r^2} \right|$$
$$P_{\mathrm{r}} < P_{\mathrm{in}}$$
$$P_{\mathrm{in}}$$
$$P_{\mathrm{r}} = P_{\mathrm{in}}$$
3. **What is the polarization of an antenna, polarization matching, and polarization correction?**
Polarization (Maximum Gain Direction):
- Linear Polarization: Parallel (Parallel to the receiving surface), Vertical (Perpendicular to the receiving surface).
- Circular Polarization: Right-hand (Right-hand circular), Left-hand (Left-hand circular).
Circular Polarization: Equal to the right-hand and left-hand circularly polarized wave components.
Page 41
The page contains a series of notes and diagrams related to antenna theory. Here's a breakdown of the content:
1. **Polarization Matching:**
- **Polarization Matching:** The receiving and transmitting antennas should have the same polarization.
- **Polarization Misalignment:** Polarization mismatch.
2.
shows a block diagram of a polarization mismatch scenario. It depicts two blocks, one labeled "Polarization Mismatch" and the other labeled "Polarization Alignment."
3. **Question 4:** Discuss the concept of a circular array and its total radiation pattern. The formula provided is:
$$ f_{\alpha}(\theta, \phi) = f_{\alpha}(\theta, \phi) \cdot f_{\alpha}(\theta, \phi) = f_{\alpha}(\theta, \phi) $$
4. **Question 5:** Discuss the radiation patterns of dipole, half-wave dipole, and full-wave dipole antennas in the E and H planes. The formulas provided are:
- **Dipole:**
$$ f_{\alpha}(\theta) = \sin(\theta) $$
- **E-plane (1st order):**
$$ \text{Circular} $$
- **H-plane (1st order):**
$$ \text{Circular} $$
- **Half-wave Dipole:**
$$ f_{\alpha}(\theta) = \frac{\cos\left(\frac{\pi}{2} \cos(\theta)\right)}{\sin(\theta)} $$
- **E-plane (1st order):**
$$ \text{Elliptical} $$
- **H-plane (1st order):**
$$ \text{Circular} $$
- **Full-wave Dipole:**
$$ f_{\alpha}(\theta) = \frac{\cos\left(\pi \cos(\theta)\right) + 1}{\sin(\theta)} $$
- **E-plane (1st order):**
$$ \text{Elliptical} $$
- **H-plane (1st order):**
$$ \text{Circular} $$
5. **Question 6:** Discuss the structure, analysis method, and equivalent circuit of a microstrip patch antenna. The formulas provided are:
- **Structure:**
$$ \text{Patch} $$
$$ \text{Ground Plane} $$
- **Analysis Formula:**
$$ f_{\alpha, E} = S_{\alpha} \left( \frac{k \beta}{2} \sin(\theta) \right) \cdot 2 \cos\left( \frac{k \beta}{2} \sin(\theta) \right) $$
$$ f_{\alpha, H} = S_{\alpha} \left( \frac{k \beta}{2} \sin(\theta) \right) \cdot 2 \cos\left( \frac{k \beta}{2} \sin(\theta) \right) $$
Page 42
**Equivalent Circuit:**
$$\frac{1}{Z_{eq}} = \frac{1}{R_{1}} + \frac{1}{R_{2}}$$
$$Z_{in} = R_{1} / 2$$
7. **Three-Element Eight-Element Analysis Method:**
$$Z_{2} \rightarrow E_{B}, E_{C} \rightarrow E_{B}^{'}, E_{C}^{'}, e_{B}, e_{C} \rightarrow Z_{1}, Z_{3}$$
$$k - \frac{\lambda}{4} \rightarrow k - \frac{\lambda}{4} \rightarrow k$$
1) **Near-field (B, C) Electric Field:**
$$E_{B, C} = j \frac{2 \pi e^{jkr}}{2 \pi r} \cdot \frac{\cos(\frac{\pi}{2} \cos \theta)}{\cos \theta} = \frac{2 \pi e^{jkr}}{\lambda} \cdot \frac{\cos(\frac{\pi}{2} \cos \theta)}{\cos \theta}$$
$$l = \frac{\lambda}{2}$$
$$E_{B}, E_{C} \text{ are in phase}$$
2) **Induced Electric Fields:**
$$E_{B} = \int_{1}^{2} E_{B} \cdot dt = - \int_{1}^{2} E_{B} \cdot dt$$
$$E_{C} = \int_{1}^{2} E_{C} \cdot dt = - \int_{1}^{2} E_{C} \cdot dt$$
3) **Left Resonator Long:**
$$B \text{ input inductive reactance (open circuit)}$$
$$C \text{ input capacitive reactance (open circuit)}$$
Page 43
4) $$I_B = e_B / Z_{B,in}, I_C = e_C / Z_{C,in}, I_B \neq I_C 90°, I_B \neq I_C 90°$$
Near-field impedance matching: $$I_B \approx I_C \approx I_0$$
5) Left-hand and right-hand waves in the near field add in phase, in the far field add in phase.
Left-hand and right-hand waves in the near field add in phase, in the far field add in phase.
8. Describe several forms of parabolic surface antennas. What types of waves do they produce, and what are their uses?
a) Parabolic surface antenna (circular face)
b) Slotted parabolic surface antenna (rectangular face)
c) Slotted parabolic surface antenna (elliptical face)
d) Parabolic surface antenna (elliptical face)
Horizontal wave emission
Vertical wave emission
Navigation radar, anti-ship radar
9. How to calculate the far-field radiation pattern of a parabolic surface antenna?
Near-field method: Use the initial wave impedance and parabolic surface reflection characteristics to find the surface currents $$E_A, H_A$$ (only for the parabolic surface).
$$H_A E_A \rightarrow J_{in} J_{es}$$
$$\rightarrow A_m A \rightarrow E \cdot H$$
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$$\rightarrow A_m A \
Page 44
10. Cassie's two analysis methods of the line.
Virtual Source Method (Equivalent Source Method)
Equivalent Polarization Method: Define the polarized surface, only one equivalent polarized surface corresponds to it.
17. Additional
Mode Classification:
1) Transverse Electric (TE) Wave, Transverse Magnetic (TM) Wave, Electric Wave, Magnetic Wave
2) Transverse Electric (TE) Wave, Transverse Magnetic (TM) Wave, Electric Wave, Magnetic Wave
3) Transverse Electric (TE) Wave, Transverse Magnetic (TM) Wave
4) Hybrid Wave (EH Wave): TE Wave and TM Wave in hybrid combination, e.g., hybrid.
Mode Transmission Conditions:
1) Electromagnetic excitation mode: Excitation and hybrid
2) Working wavelength: λ
3) Impedance matching
Page 45
No.
Date
1. Matching Network
TE10: Parallel: Helical Inductor
2. Waveguide Head
TE11: Waveguide wall near strong I2, good contact
3. Short Circuit
S-shaped flow stopper:
$$\frac{1}{Z_{a}} = \frac{1}{Z_{c1}}, \frac{1}{Z_{b3}} = \frac{1}{Z_{a}} = \frac{Z_{c1}}{Z_{a}}, Z_{b} = \frac{Z_{c1}^2}{Z_{a}}$$
$$\frac{1}{Z_{b2}} = \frac{Z_{c1}^2}{Z_{a}Z_{c2}}, \frac{1}{Z_{c1}} = \frac{1}{Z_{b3}} = \frac{Z_{a}Z_{c1}}{Z_{c1}^2}, Z_{c} = \frac{Z_{a}Z_{c1}^2}{Z_{c1}^2}$$
When Za ≈ 0, $$\left(\frac{Z_{c1}^2}{Z_{c1}}\right) \ll 1$$, Zc ≈ 0.
4. Attenuator
Rotating polarized attenuator: TE10 → TE11 → TE10 → TE11
$$[S] = \begin{bmatrix} 0 & \cos\theta \\ \cos\theta & 0 \end{bmatrix}$$
5. Mode Suppressor
TE01 mode suppressor
For TE10:
$$[S] = \begin{bmatrix} -1 & 0 \\ 0 & -1 \end{bmatrix}$$
For through mode:
$$[S] = \begin{bmatrix} e^{-j\omega t} & 0 \\ 0 & e^{j\omega t} \end{bmatrix}$$
6. Waveguide T-branch: (lossless end network)
$$[S] = \frac{1}{2} \begin{bmatrix} 1 & 1 \\ 1 & -1 \end{bmatrix}$$
Page 46
Properties of Three-Port Networks:
1. It is impossible to have all three ports matched simultaneously.
2. It is impossible to have two ports matched simultaneously, otherwise it becomes a two-port network.
7. 3dB Ideal Power Divider (Three-Port Network):
$$
[S] = \begin{bmatrix}
0 & \frac{1}{\sqrt{2}} & \frac{1}{\sqrt{2}} \\
\frac{1}{\sqrt{2}} & 0 & 0 \\
\frac{1}{\sqrt{2}} & 0 & 0
\end{bmatrix}
$$
1 → 2, 3: Power Divider
2, 3 → 1: Combiner.
8. Magic T Branch (Four-Port Network):
$$
\text{Structural Symmetry: } S_{21} = S_{31}, S_{22} = S_{33}
$$
$$
S_{41} = S_{14} = 0, S_{24} = -S_{34}
$$
$$
S_{ij} = S_{ji}
$$
1, 4 Port Matching: S_{11}, S_{44} = 0
$$
\text{No loss: } [S]^{H} \cdot [S] = I.
$$
$$
[S] = \frac{1}{\sqrt{2}} \begin{bmatrix}
0 & 1 & 1 & 0 \\
1 & 0 & 0 & 1 \\
1 & 0 & 0 & -1 \\
0 & 1 & -1 & 0
\end{bmatrix}
$$
9. Waveguide Branch Coupler (Four-Port Network):
1 → 4: Direct
2 → 1: Isolator
3 → 4: Coupler
4 → 2: Isolator
$$
\text{Structural Symmetry: } S_{11} = S_{22} = S_{33} = S_{44}, S_{12} = S_{21}, S_{13} = S_{31}, S_{14} = S_{41}
$$
$$
\text{No loss, no coupling: } S_{12} \text{ and } S_{13} \text{ are } 90^\circ.
$$
$$
[S] = \begin{bmatrix}
0 & S_{12} & S_{13} & 0 \\
S_{12} & 0 & 0 & S_{13} \\
S_{13} & 0 & 0 & S_{12} \\
0 & S_{13} & S_{12} & 0
\end{bmatrix}
$$
Page 47
10. Circular Polarizer: (Unidirectional Waveguide Network)
- Geometrically: Two-Port
- Electrically: Four-Port (Horizontal Polarization TE_{11}°, Vertical Polarization TE_{11}°)
- Each Port Matching: S_{ii} = 0
- Horizontal Polarization: S_{12} = S_{14} = S_{23} = S_{34} = 0
- Symmetry: S_{ij} = S_{ji}
- Vertical Polarization and Horizontal Polarization at π/2: S_{42} = j e^{-jφ}
- Assume S_{31} = e^{-jφ}, then S_{12} = j e^{-jφ}
$$
[S] = \begin{bmatrix}
0 & 0 & e^{-jφ} & 0 \\
0 & 0 & 0 & j e^{-jφ} \\
e^{-jφ} & 0 & 0 & 0 \\
0 & j e^{-jφ} & 0 & 0
\end{bmatrix}
$$
11. Rotational Symmetry at Four-Port (Unidirectional Waveguide Network)
- Each Port Matching: S_{ii} = 0
- Rotational Symmetry: S_{12} = S_{23} = S_{34} = S_{45} = S_{51} = S_{10} = S_{20} = S_{25} = S_{35}
- Symmetry: S_{ij} = S_{ji}
- Unidirectional: [S]^{H} [S] = I_{5}
$$
\Rightarrow |S_{12}| = |S_{13}| = \frac{1}{2}
$$
$$
S_{12} = \frac{1}{2}, S_{13} = \frac{1}{2} e^{jφ}, \text{ then }
$$
$$
S_{13}^{*} S_{12} + S_{12}^{*} S_{13} + |S_{12}|^{2} = 0
$$
$$
\text{Result: } \frac{1}{4} e^{jφ} + \frac{1}{4} e^{-jφ} + \frac{1}{4} = 0
$$
$$
\therefore \cos φ = -\frac{1}{2}, φ = 120°
$$
12. Circular Polarizer: (Unidirectional Waveguide Network)
$$
[S] = \begin{bmatrix}
0 & 0 & 1 \\
1 & 0 & 0 \\
0 & 1 & 0
\end{bmatrix}
$$