An amplifi er with open-loop gain a(s) 5 100y [(1 1 sy103 ) 3 (1 1 sy105 )] is placed in a negative-feedback loop. (a) Derive an expression for the closed-loop gain A(s) as a function of the feedback...

An amplifi er with open-loop gain a(s) 5 100y [(1 1 sy103 ) 3 (1 1 sy105 )] is placed in a negative-feedback loop. (a) Derive an expression for the closed-loop gain A(s) as a function of the feedback factor , and fi nd the value of that causes the poles of A(s) to be coincident. What is their common value? (b) Find the crossover frequency fx and, hence, the phase margin m.