ellipall.m

使用Matlab实现了FIR与IIR滤波器

function [ output_args ] = Untitled2( input_args )
%UNTITLED2 Summary of this function goes here
%  Detailed explanation goes here
ft=22050;
Wpl=2*1000/ft;
Wsl=2*1200/ft;
Rp = 1;
Rs = 100;
[Nl,Wnl] = ellipord(Wpl,Wsl,Rp,Rs);
[bl,al] = ellip(Nl,Rp,Rs,Wnl,'low');
[hl,wl]= freqz(bl,al);
subplot(3,1,1);
plot (wl/pi,20*log10(abs(hl)));grid;
axis([0,1,-200,0]);
xlabel('w/pi'); ylabel('Gain, dB');
title('Type Ellip Lowpass Filter');
Wph=2*5000/ft;
Wsh=2*4800/ft;
Rp = 1;
Rs = 100;
[Nh,Wnh] = ellipord(Wph,Wsh,Rp,Rs);
[bh,ah] = ellip(Nh,Rp,Rs,Wnh,'high');
[hh,wh]= freqz(bh,ah);
subplot(3,1,2);
plot (wh/pi,20*log10(abs(hh)));grid;
axis([0,1,-200,0]);
xlabel('w/pi'); ylabel('Gain, dB');
Wp1b =2*1200/ft;
Wp2b=2*3000/ft;
Ws1b = 2*1000/ft;
Ws2b=2*3200/ft;
Wpb=[Wp1b,Wp2b];
Wsb=[Ws1b,Ws2b];
Rp = 1;
Rs = 100;
[Nb,Wnb] = ellipord(Wpb,Wsb,Rp,Rs);
[bb,ab] = ellip(Nb,Rp,Rs,Wnb);
[hb,wb]= freqz(bb,ab);
subplot(3,1,3);
plot (wb/pi,20*log10(abs(hb)));grid;
axis([0,1,-200,0]);
xlabel('w/pi'); ylabel('Gain, dB');
title('Type Ellip Bandpass Filter');