IIR ELLIPTIC

% LPF

clc;

clear;

close all;

%LPF of cut off 500Hz

fp=500;

fs=600;

samp=2000;

ap=.5;

as=40;

wp=fp/(samp/2);

ws=fs/(samp/2);

[N,wn]=ellipord(wp,ws,ap,as);

[b,a]=ellip(N,ap, as,wn);

[H,W]=freqz(b,a,256);

plot(W/(2*pi),20*log10(abs(H)))

n=0:1/samp:1;

x=cos(2*pi*200*n)+cos(2*pi*700*n);

figure

subplot 211, plot(n,abs(fft(x)))

y=filter(b,a,x);

subplot 212, plot(n,abs(fft(y)))

% HPF

clc;

clear;

close all;

%HPF of cut off 500Hz

fs=500;

fp=600;

samp=2000;

ap=.5;

as=40;

wp=fp/(samp/2);

ws=fs/(samp/2);

[N,wn]=ellipord(wp,ws,ap,as);

[b,a]=ellip(N,ap, as,wn,'high');

[H,W]=freqz(b,a,256);

plot(W/(2*pi),20*log10(abs(H)))

n=0:1/samp:1;

x=cos(2*pi*200*n)+cos(2*pi*700*n);

figure

subplot 211, plot(n,abs(fft(x)))

y=filter(b,a,x);

subplot 212, plot(n,abs(fft(y)))

%BPF

clc;

clear;

close all;

%BPF of pass 400-600Hz

fs1=300;

fp1=400;

fp2=600;

fs2=700;

samp=2000;

ap=.5;

as=40;

wp=[fp1 fp2]/(samp/2);

ws=[fs1 fs2]/(samp/2);

[N,wn]=ellipord(wp,ws,ap,as);

[b,a]=ellip(N,ap, as,wn,'bandpass');

[H,W]=freqz(b,a,256);

plot(W/(2*pi),20*log10(abs(H)))

n=0:1/samp:1;

x=cos(2*pi*200*n)+cos(2*pi*500*n)+cos(2*pi*800*n);

figure

subplot 211, plot(n,abs(fft(x)))

y=filter(b,a,x);

subplot 212, plot(n,abs(fft(y)))

%BSF

clc;

clear;

close all;

%BSF of stop 400-600Hz

fp1=300;

fs1=400;

fs2=600;

fp2=700;

samp=2000;

ap=.5;

as=40;

wp=[fp1 fp2]/(samp/2);

ws=[fs1 fs2]/(samp/2);

[N,wn]=ellipord(wp,ws,ap,as);

[b,a]=ellip(N,ap, as,wn,'stop');

[H,W]=freqz(b,a,256);

plot(W/(2*pi),20*log10(abs(H)))

n=0:1/samp:1;

x=cos(2*pi*200*n)+cos(2*pi*500*n)+cos(2*pi*800*n);

figure

subplot 211, plot(n,abs(fft(x)))

y=filter(b,a,x);

subplot 212, plot(n,abs(fft(y)))