ms10_3.m

《数字信号处理实验(MATLAB版)》这

b=[0.1,-0.4,0.4,-0.1];
a=[1,0.3,0.55,0.2];
n=(0:1000)*pi/1000;
[h,w]=freqz(b,a,n);
db=20*log10(abs(h));
subplot(2,2,1),plot(w/pi,abs(h));grid
axis([0,1,1.1*min(abs(h)),1.1*max(abs(h))]);
title('幅频特性');
subplot(2,2,2),plot(w/pi,angle(h));grid
axis([0,1,1.1*min(angle(h)),1.1*max(angle(h))]);
title('相频特性');
subplot(2,2,3),plot(w/pi,db);grid
axis([0,1,-100,5]);
title('幅频特性');
subplot(2,2,4),zplane(b,a);
title('零极点分布');