p144.m

反馈控制系统分析与设计的有关程序和例子 涉及面广 很详细 值得参考

wn=1; z=0.1; K=0:.005:0.2; 
C1=(-z+sqrt(z^2-K))*wn; C2=(-z-sqrt(z^2-K))*wn;
plot(real(C1),imag(C1),real(C2),imag(C2))
figure, wn=1; z=0.5; K=0:.05:2; 
C1=(-z+sqrt(z^2-K))*wn; C2=(-z-sqrt(z^2-K))*wn;
plot(real(C1),imag(C1),real(C2),imag(C2))