Analysis of( Causal!LTI Feedback Systems: Black's Formula CT System (t)- e H(s) Loop r G(s) Y H X()1+G(s)H( Blacks formula(1920s) orward gain Closed-loop system function loop gain Forward gain-total gain along the forward path from the input to the output Loop gain-total gain around the closed loopAnalysis of (Causal!) LTI Feedback Systems: Black’s Formula CT Syste m Black’s formula (1920’s) Closed -loop system function = forward gain 1 - loop gain Forward gain — total gain along the forward path from the input to the output Loop gain — total gain around the closed loop