lj31.m

来自「基于matlab的数字信号处理程序」· M 代码 · 共 21 行

wp=0.2*pi;
ws=0.3*pi;
Rp=1;
Rs=15;
Fs=0.5;
Ts=1/Fs;
[N,Wn]=buttord(wp,ws,Rp,Rs,'s'); 
[z,p,k]=buttap(N);
[Bap,Aap]=zp2tf(z,p,k);
[b,a]=lp2lp(Bap,Aap,Wn);
[bz,az] =impinvar(b,a,Fs);
[H,W]=freqz(bz,az);
plot(W*Fs/(2*pi),abs(H));
grid
xlabel('频率/Hz')
ylabel('频率响应幅度')
n=0:1:15;
x=cos(0.135*pi*n);figure(2),stem(x);
y=conv(x,impinvar(b,a,Fs));
y1=fft(y);
figure(3),stem(y1);