For the signal flow graph show in figure, the transfer function is C(s)/R(s)=
There is one forward path and two loops, P1=G1G2G3 L1=−H1G1G2, L2=−H2G2G3 T.F.=P1Δ1Δ =G1G2G3[1−0]1+H1G1G2+H2G2G3 =G1G2G31+G1G2H1+G2G3H2