% exa4-17_cheb2band.m , for example 4-17
% using chebyshev II filter to design bandpass DF

clear all;
Wpl=100;
Wph=250;
Wp=[Wpl,Wph];
Rp=3;
Wsl=50;
Wsh=300;
Ws=[Wsl,Wsh];
Rs=30;
Fs=1000;
[N,Wn]=cheb2ord(Wp/(Fs/2),Ws/(Fs/2),Rp,Rs);
[b,a]=cheby2(N,Rp,Wn);
freqz(b,a,512,1000)