ellipl.asv

使用Matlab实现了FIR与IIR滤波器

function [ output_args ] = Untitled8( input_args )
%UNTITLED8 Summary of this function goes here
%  Detailed explanation goes here
ft=22050;
Wp=2*1000/ft;
Ws=2*1200/ft;
wps=tan(Wp*pi/2);
wss=tan(Ws*pi/2);
Rp = 1;
Rs = 100;
[N,Wn] = ellipord(Wp,Ws,Rp,Rs);
[b,a] = ellip(N,Rp,Rs,Wn,'low');
[h,w]= freqz(b,a);
subplot(2,1,1);
plot (w/pi,20*log10(abs(h)));grid;
xlabel('w/pi'); ylabel('Gain, dB');
title('Type Ellip Lowpass Filter');
[n,wn] = ellipord(wps,wss,Rp,Rs,'s');
[B,A] = ellip(n,Rp,Rs,wn,'low','s');
[num,den]=bilinear(B,A,);
[H,W]= freqz(num,den);
subplot(2,1,2);
plot (W/pi,20*log10(abs(H)));grid;
xlabel('w/pi'); ylabel('Gain, dB');
title('Type Ellip Lowpass Filter');