passband_edge = 0.2*pi;
stopband_edge = 0.3*pi;
passband_attenuation = 0.3;
stopband_attenuation = 30;
Td = 1;

% Calculating Omega = omega/Td for passband and stopband
pass_frequency = passband_edge/Td;
stop_frequency = stopband_edge/Td;

% getting minimum order of filter as well as cutoff-frequency
[n, cf] = cheb2ord(pass_frequency, stop_frequency, passband_attenuation, stopband_attenuation, 's');

% Getting transferfunction of continous filter
[b, a] = cheby2(n, stopband_attenuation, cf, 'low', 's');
transferfunction = tf(b, a);

% using impulse invarianse and sampling with Td to achieve digital filter using impulse invarians
[num_impulse, den_impulse] = impinvar(b, a, 1/Td);
Hz_impulse = tf(num_impulse, den_impulse, 1/Td);

% getting digital filter using bilinear transform
[num_bilinear, den_bilinear] = bilinear(b, a, 1/Td);
Hz_bilinear = tf(num_bilinear, den_bilinear, 1/Td);

%%% Plotting filter designed using impulse invarians

freqz(num_impulse, den_impulse)
freqz(num_bilinear, den_bilinear)