www.pudn.com > controlsystem.ZIP > EX3029.M

% Example 3.29 
% 
a=[-2.1 -1.87 -0.203 0.894 ; 1 0 0 0; 0 1 0 0; 0 0 1 0]; 
b=[1 0 0 0]'; 
c=[0 0 -1 -2]; 
d=0; 
[num,den]=ss2tf(a,b,c,d); 
num=-1*num; 
[z,p,k]=tf2zp(num,den); 
p 
figure(1) 
nyquist(num,den) 
title('Nyquist Plot')