ms10_4.m

《数字信号处理实验(MATLAB版)》这

b=[0.1321,0, 0.3963,0, 0.3963,0,0.1321];
a=[1,0,-0.34319,0, 0.60439, 0,-0.20407];
[db,mag,pha,grd,w]=freqz_m(b,a);
subplot(2,2,1),plot(w/pi,mag,'k');grid %作绝对幅度频响图
axis([0,1,1.1*min(mag),1.1*max(mag)]);
title('幅频特性（V）');
subplot(2,2,2),plot(w/pi,pha,'k');grid  %作相位频响图
axis([0,1,1.1*min(pha),1.1*max(pha)]);
title('相频特性');
subplot(2,2,3),plot(w/pi,db,'k');grid   %作相对幅度频响图
axis([0,1,-100,5]);
title('幅频特性（dB）');
subplot(2,2,4),plot(w/pi,grd,'k');grid  %作系统的群迟延图
title('群迟延');