Chapter 8 - Feedback

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Chapter 8 - Feedback
1 - Desensitize The Gain 2 - Reduce Nonlinear
Distortions 3 - Reduce The Effect of Noise 4
Control The Input And Output Impedances 5
Extend The Bandwidth Of The Amplifier
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The General Feedback Structure
A
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The General Feedback Structure MATLAB /
SIMULINK Anyone interested to put together an
Introduction to MATLAB / Simulink PowerPoint
Presentation plus some examples?
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The General Feedback Structure Exercise 8.1
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The General Feedback Structure Exercise 8.1
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Some Properties of Negative Feedback Gain
Desensitivity
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Some Properties of Negative Feedback Bandwidth
Extension
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Some Properties of Negative Feedback Noise
Reduction, Reduction of Nonlinear
Distortion Read and discuss in class
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The Four Basic Feedback Topologies Voltage
Amplifiers (V/V) Current Amplifiers
(I/I) Transconductance Amplifiers
(I/V) Transresistance Amplifiers (V/I)
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The Four Basic Feedback Topologies
The four basic feedback topologies (a)
voltage-sampling series-mixing (series-shunt)
topology (b) current-sampling shunt-mixing
(shunt-series) topology (c) current-sampling
series-mixing (series-series) topology (d)
voltage-sampling shunt-mixing (shunt-shunt)
topology.
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The Four Basic Feedback Topologies Voltage
Amplifiers VCVS Input Resistance High Output
Resistance Low Feedback sample the output
voltage Voltage-sampling series-mixing Current
Amplifiers Transconductance
Amplifiers Transresistance Amplifiers
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The Shunt-Series Feedback Amplifier The Ideal
Situation

• The series-shunt feedback amplifier
• ideal structure
• equivalent circuit.

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The Shunt-Series Feedback Amplifier The
Practical Situation

• Derivation of the A circuit and ? circuit for the
  series-shunt feedback amplifier.
• (a) Block diagram of a practical series-shunt
  feedback amplifier.
• The circuit in (a) with the feedback network
  represented by its h parameters.
• (c) The circuit in (b) after neglecting h21.

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The Shunt-Series Feedback Amplifier Summary For
Finding the A Circuit b for a given series-shunt
feedback amplifier.
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The Shunt-Series Feedback Amplifier Example 8.1
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The Shunt-Series Feedback Amplifier Exercise 8.4
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The Series-Series Feedback Amplifier The Ideal
Case
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The Series-Series Feedback Amplifier The Ideal
Practical Case
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The Series-Series Feedback Amplifier For Finding
the A Circuit b for a given series-series
feedback amplifier
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The Series-Series Feedback Amplifier Example 8.2
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The Series-Series Feedback Amplifier Example 8.2
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The Series-Series Feedback Amplifier Example 8.2
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The Series-Series Feedback Amplifier Example 8.2
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The Shunt-Shunt and Shunt-Series Feedback
Amplifiers Shunt Configuration
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The Shunt-Shunt and Shunt-Series Feedback
Amplifiers
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The Shunt-Shunt and Shunt-Series Feedback
Amplifiers Example 8.3
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The Shunt-Series Feedback Amplifier
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The Shunt-Series Feedback Amplifier
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The Shunt-Series Feedback Amplifier Example 8.4
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The Shunt-Series Feedback Amplifier Example 8.4
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Determining Loop Gain
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The Stability Problem and Margins
Nyquist
Closed-Loop Transfer Function
Root-Locus
Bode
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The Stability Problem and Margins
Nyquist
Closed-Loop Transfer Function
Root-Locus
Bode
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The Nyquist Plot
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Effect of Feedback On The Amplifier Poles
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Stability Study Using Bode Plots
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Frequency Compensation
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Spice Simulation Examples