K=1;
tau=1;
ep=1;
%rho = ep/tau
sis1=tf(K*[0*ep 1],[tau 1]);
sis2=tf(K*[0.4*ep 1],[tau 1]);
sis3=tf(K*[0.8*ep 1],[tau 1]);
sis4=tf(K*[ep 1],[tau 1]);
sis5=tf(K*[1.2*ep 1],[tau 1]);
sis6=tf(K*[1.6*ep 1],[tau 1]);
sis7=tf(K*[2*ep 1],[tau 1]);
step(sis1,sis2,sis3,sis4,sis5,sis6,sis7);
legend('\rho=0','\rho=0.4','\rho=0.8','\rho=1','\rho=1.2','\rho=1.6','\rho=2');
