firall.m

使用Matlab实现了FIR与IIR滤波器

function [ output_args ] = Untitled1( input_args )
%UNTITLED1 Summary of this function goes here
%  Detailed explanation goes here
ft=22050;
fcutsl=[1000 1200];
magsl = [1 0];
devsl= [(1-10^(-1/20)),10^(-100/20)];
[Nl,Wnl,betal,ftypel] = kaiserord(fcutsl,magsl,devsl,ft);
bl = fir1(Nl,Wnl, kaiser(Nl+1,betal));
[hl,wl] = freqz(bl,1);
subplot(3,1,1);
plot(wl/pi,20*log10(abs(hl)));grid;
xlabel('w/pi'); ylabel('Gain, dB');
title('Fir Lowpass Fiter');
fcutsh=[4800 5000];
magsh = [0 1];
devsh = [10^(-100/20),(1-10^(-1/20))];
[Nh,Wnh,betah,ftypeh] = kaiserord(fcutsh,magsh,devsh,ft);
bh= fir1(Nh,Wnh,'high',kaiser(Nh+1,betah));
[hh,wh] = freqz(bh,1);
subplot(3,1,2);
plot(wh/pi,20*log10(abs(hh)));grid;
xlabel('w/pi'); ylabel('Gain, dB');
title('Fir Highpass Filter');
fcutsb=[1000 1200 3000 3200];
magsb = [0 1 0];
devsb = [10^(-100/20),(1-10^(-1/20)),10^(-100/20)];
[Nb,Wnb,betab,ftypeb] = kaiserord(fcutsb,magsb,devsb,ft);
bb = fir1(Nb,Wnb,kaiser(Nb+1,betab));
[hb,wb] = freqz(bb,1);
subplot(3,1,3);
plot(wb/pi,20*log10(abs(hb)));grid;
xlabel('w/pi'); ylabel('Gain, dB');
title('Fir Bandpass Filter');