Consider a feedback amplifier for which the open-loop gain is given by
(a) Determine the frequency f180 at which the phase of A( f ) is -180 degrees.
(b) For β = 0.0045, determine the magnitude of the loop gain T ( f ) at the frequency f = f180 and determine the phase of A(f)when |T ( f )| = 1. Determine the closed-loop, low-frequency gain. Is the system stable or unstable?
(c) Repeat part (b) for β = 0.15.