firlowpass.m

matlab的滤波器

fb=1000;fc=1200;fs=44000;
wb=2*pi*fb/fs;
wc=2*pi*fc/fs;
deltaw=(wc-wb)/(2*pi);
N0=ceil((100-7.95)/(14.36*deltaw))+1;
N=N0+mod(N0+1,2);
beta=0.1102*(100-8.7);
[b,a]=fir1(N-1,wb/pi,'low',kaiser(N,beta));
[x1,fs]=wavread('music');
x2=fftfilt([b,a],x1);
sound(x2,44100);f=fft(x2,length(x1));
printf(x2,abs(f),abs(length(x1)),b,a);