lab3iirauto.m

来自「基于双线性变换法的IIR滤波器范例 该滤波器为低通原型 可根据需要自行转换成高通」· M 代码 · 共 21 行

close all;
clear all;

[Y,FS,NBITS]=wavread('angel.wav');

figure(1);
plot(Y);
Fs = 14000;
Wp = [2*pi*3000/Fs 2*pi*4000/Fs]; 
Ws = [2*pi*2700/Fs 2*pi*4300/Fs];
[N, Wn] = buttord(Wp/pi, Ws/pi, 0.1, 70)
[num, den] = butter(N, Wn);
[H, W] = freqz(num, den, 256);
figure(2);
plot(W/pi, 20*log10(abs(H)));
grid;
Z = filter(num,den,Y);
figure(3);
plot(Z);
wavwrite(Z,FS,NBITS,'new.wav');
axis([0 180000 -1 1])