MATLAB: Need help to determine stopband

bandpass filterstopband

I got a frequency of 6 – 16 Hz to pass through. but how do i determine what is my stopband?
xd = double(myRecording); % Convert to ‘double’
Fs = 8000; % Sampling Frequency
Fn = Fs/2; % Nyquist Frequency
Fpb = [6 16]/Fn; % Passband
Fsb = []/Fn; % Stopband

Best Answer

If you’re designing a bandpass filter, everything within [6 16] Hz (normalised by ‘Fn’ as you correctly compute) is your passband. Everything else is your stopband by definition, so you don’t need to define it specifically. If you need to define passband and stopband ripple (a requirment of buttord and related functions), choose 1 and 10 dB respectively.