When operated open loop, an amplifier A(s) is modeled by XXXXXXXXXXIts 3 dB bandwidth is kHz and its dc gain, , is 80 dB. When connected with negative feedback for unity gain (i.e. ), the closed loop...

When operated open loop, an amplifier A(s) is modeled by (5.34). Its 3 dB bandwidth is kHz and its dc gain, , is 80 dB. When connected with negative feedback for unity gain (i.e. ), the closed loop amplifier is stable with 45° phase margin. The amplifier is now to be used with negative feedback for a closedloop dc gain of 20 dB.

a. What is the resulting bandwidth of the closed-loop amplifier?

b. What is the resulting phase margin?

c. If , , and can each vary (independently) by %, what are the minimum bandwidth and phase margin that can be guaranteed for the closed-loop feedback amplifier with 20 dB of dc gain?