Chebyshev Type 2 Analog Band Stop Filter Using Function (Matlab 2012a)

Program:

clc;
clear all;
rp = input('Enter the passband ripple = ');
rs = input('Enter the stopband ripple = ');
wp = input('Enter the passband frequency = ');
ws = input('Enter the stopband frequency = ');
fs = input('Enter the sampling frequency = ');
w1 = 2*wp/fs;
w2 = 2*ws/fs;
[n] = cheb2ord(w1,w2,rp,rs,'s');
wn = [w1 w2];
[b,a] = cheby2(n,rs,wn,'stop','s');
w = 0:0.01:pi;
[h,om] = freqs(b,a,w);
m = 20*log10(abs(h));
an = angle(h);
subplot(2,1,1);
plot(om/pi,m);
subplot(2,1,1);
plot(om/pi,m);
title('Magnitude Response');
ylabel('Gain in dB ---->');
xlabel('Normalised Frequency ---->');
grid on;
subplot(2,1,2);
plot(om/pi,an);
title('Phase Response');
xlabel('Normalised Frequency ---->');
ylabel('Phase in radians ---->');
grid on;

Output:

Enter the passband ripple = 0.25
Enter the stopband ripple = 30
Enter the passband frequency = 1300
Enter the stopband frequency = 2000
Enter the sampling frequency = 8000

Waveform: