m1.m

来自「FIR、IIR数字滤波器的Matlab仿真程序」· M 代码 · 共 30 行

fp=480;
fs=520;
Wp=2*pi*fp;
Ws=2*pi*fs;
Rp=3;
Rs=20;
[n,Wn]=buttord(Wp,Ws,Rp,Rs,'s');
[z,p,k]=buttap(n);
[b1,a1]=zp2tf(z,p,k);
[h1,w1]=freqs(b1,a1);
mag1=abs(h1);
subplot(221);
semilogx(w1,mag1);
fw=40;
bw=2*pi*fw;
[b2,a2]=lp2bp(b1,a1,Wn,bw);
[h2,w2]=freqs(b2,a2);
mag2=abs(h2);
subplot(222);
plot(20*log10(mag2));
fo=2000;
[bz,az]=impinvar(b2,a2,2000);
[hz,w]=freqz(bz,az);
magz=abs(hz);
phz=unwrap(angle(hz));
subplot(223);
plot(magz);
subplot(224);
plot(phz);