MATLAB控制系统仿真与实例详解（附书光盘）

				wn=[0.1:0.1:1]; 
				z=0.55;
				t=0:0.1:12; 
				hold on 
				for i=1:length(wn) 
				Gc=tf(wn(i)^2,[1,2*z*wn(i),wn(i)^2]); 
				step(Gc,t) 
				end 
				hold off
				title('阶跃响应曲线');
				grid