Matlab Yasir252 Exclusive -

If you are trying to implement the code from this paper, here is a general workflow:

%% 4. DIGITAL FILTERING % Design a 4th-order lowpass Butterworth filter (cutoff 1 Hz) fs = 100; % Sampling frequency (100 Hz) fc = 1; % Cutoff frequency [b, a] = butter(4, fc/(fs/2), 'low'); matlab yasir252