1 figure 8.1 general structure of the feedback amplifier. this is a signal-flow diagram, and the...
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![Page 1: 1 Figure 8.1 General structure of the feedback amplifier. This is a signal-flow diagram, and the quantities x represent either voltage or current signals](https://reader035.vdocuments.net/reader035/viewer/2022070323/56649d4b5503460f94a283c6/html5/thumbnails/1.jpg)
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Figure 8.1 General structure of the feedback amplifier. This is a signal-flow diagram, and the quantities x represent either voltage or current signals.
The General Feedback Structure
FeedbackFeedback
1o
fs
x AA
x A
![Page 2: 1 Figure 8.1 General structure of the feedback amplifier. This is a signal-flow diagram, and the quantities x represent either voltage or current signals](https://reader035.vdocuments.net/reader035/viewer/2022070323/56649d4b5503460f94a283c6/html5/thumbnails/2.jpg)
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Gain Desensitivity
2(1 )f
dAdA
A
1
1f
f
dA dA
A A A
1fA
![Page 3: 1 Figure 8.1 General structure of the feedback amplifier. This is a signal-flow diagram, and the quantities x represent either voltage or current signals](https://reader035.vdocuments.net/reader035/viewer/2022070323/56649d4b5503460f94a283c6/html5/thumbnails/3.jpg)
3Figure 8.2 Illustrating the application of negative feedback to improve the signal-to-noise ratio in amplifiers.
Noise Reduction
1 2 1
1 2 1 21 1o s n
A A AV V V
A A A A
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Figure 8.3 Illustrating the application of negative feedback to reduce the nonlinear distortion in amplifiers. Curve (a) shows the amplifier transfer characteristic without feedback. Curve (b) shows the characteristic with negative feedback ( 0.01) applied.
Reduction in Nonlinear Distortion
![Page 5: 1 Figure 8.1 General structure of the feedback amplifier. This is a signal-flow diagram, and the quantities x represent either voltage or current signals](https://reader035.vdocuments.net/reader035/viewer/2022070323/56649d4b5503460f94a283c6/html5/thumbnails/5.jpg)
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Voltage-Mixing Voltage-Sampling (Series–Shunt) Feedback
voltage amplifier
![Page 6: 1 Figure 8.1 General structure of the feedback amplifier. This is a signal-flow diagram, and the quantities x represent either voltage or current signals](https://reader035.vdocuments.net/reader035/viewer/2022070323/56649d4b5503460f94a283c6/html5/thumbnails/6.jpg)
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Current-Mixing Current-Sampling (Shunt–Series) Feedback
current amplifier
let Is increase …
![Page 7: 1 Figure 8.1 General structure of the feedback amplifier. This is a signal-flow diagram, and the quantities x represent either voltage or current signals](https://reader035.vdocuments.net/reader035/viewer/2022070323/56649d4b5503460f94a283c6/html5/thumbnails/7.jpg)
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Voltage-Mixing Current-Sampling (Series–Series) Feedback
transconductance amplifier
![Page 8: 1 Figure 8.1 General structure of the feedback amplifier. This is a signal-flow diagram, and the quantities x represent either voltage or current signals](https://reader035.vdocuments.net/reader035/viewer/2022070323/56649d4b5503460f94a283c6/html5/thumbnails/8.jpg)
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Current-Mixing Voltage-Sampling (Shunt–Shunt) Feedback
transresistance amplifier
![Page 9: 1 Figure 8.1 General structure of the feedback amplifier. This is a signal-flow diagram, and the quantities x represent either voltage or current signals](https://reader035.vdocuments.net/reader035/viewer/2022070323/56649d4b5503460f94a283c6/html5/thumbnails/9.jpg)
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Figure 8.8 The series–shunt feedback amplifier: (a) ideal structure and (b) equivalent circuit.
The Series–Shunt Feedback Amplifier
![Page 10: 1 Figure 8.1 General structure of the feedback amplifier. This is a signal-flow diagram, and the quantities x represent either voltage or current signals](https://reader035.vdocuments.net/reader035/viewer/2022070323/56649d4b5503460f94a283c6/html5/thumbnails/10.jpg)
10Figure 8.10 Derivation of the A circuit and circuit for the series–shunt feedback amplifier. (a) Block diagram of a practical series–shunt feedback amplifier. (b) The circuit in (a) with the feedback network represented by its h parameters.
The Practical Situation
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Figure 8.11 Summary of the rules for finding the A circuit and for the voltage-mixing voltage-sampling case of Fig. 8.10(a).
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Figure 8.12 Circuits for Example 8.1.
Example 8.1