In MATLAB, use feedback() command to obtain the closed loop transfer function. Do not use L/(1 L).

Always use feedback() command to compute the closed loop transfer functions. L/(1+L) sometimes doesn't do the cancellation properly.

The Gang of Four can be obtained by:

S: feedback(1,L)

T: feedback(L,1)

PS: feedback(P,C)

CS: feedback(C,P)

--Shuo