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Published byDoris Franklin Modified over 9 years ago
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Feedback
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8.4 The Series-Shunt Feedback Amplifier 8.4.1 The Ideal Situation
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8.4 The Series-Shunt Feedback Amplifier 8.4.1 The Ideal Situation (cont.) Series mixing
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8.4 The Series-Shunt Feedback Amplifier 8.4.1 The Ideal Situation (cont.) Shunt sampling
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8.5 The Series-Series Feedback Amplifier 8.5.1 The Ideal Situation Series mixing
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8.5 The Series-Series Feedback Amplifier 8.5.1 The Ideal Situation (cont.) Series sampling
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8.6 The Shunt-Shunt and Shunt-Series Feedback Amplifier 8.6.1 The Shunt-Shunt Configuration
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8.6 The Shunt-Shunt and Shunt-Series Feedback Amplifier 8.6.3 The Shunt-Series Configuration
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8.6 The Shunt-Shunt and Shunt-Series Feedback Amplifier 8.6.3 Summary R i R if : Mixing Voltage (series) mixing always increases the input resistance. Current (shunt) mixing always reduces it. R o R of : Sampling Voltage (shunt) sampling always reduces the output resistance Current (series) sampling increases it
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8.8 The Stability Problem 8.8.1 Transfer Function of the Feedback Amplifier Open-loop gain: A, A(s) Loop gain: A , A(s) (s) Close-loop gain: Oscillator: =-1, zero input, infinite output
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8.8 The Stability Problem 8.8.2 The Nyquist Plot
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8.9 Effect of Feedback on the Amplifier Poles 8.9.1 Stability and Pole Location Figure 8.29 Relationship between pole location and transient response.
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8.9 Effect of Feedback on the Amplifier Poles 8.9.2 Poles of the feedback amplifier Simplified case
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8.10 Stability Study Using Bode Plots 8.10.1 Gain and Phase Margin
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8.10 Stability Study Using Bode Plots 8.10.2 Effect of Phase Margin on Closed-loop Response Zero margin?
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8.10 Stability Study Using Bode Plots 8.10.3 An Alternative Approach for Investigating Stability |AB|<1 20log|A| < 20log(1/ ) The closed-loop amplifier will be stable if the 20log(1/ ) line intersects the 20log|A| curve at a point on the -20-dB/decade segment.
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8.11 Frequency Compensation 8.11.1 Theory 20 40 60 80 100 10 4 10 5 10 6 10 7 10 8 1010 3 f(Hz) dB -20dB/decade -40dB/decade -60dB/decade A A’ Y Y’ Four poles Simplest Reduced the bandwidth
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Homework: 8.37, 8.43, 8.47, Ex-8.14, 8.70, 8.76, 8.77, 8.79
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