Ideal Filter Implementation for Low-Pass and Band-Pass Filtering

% y = filter(sig, fmin, fmax, fs) % Performs ideal filtering on a signal to achieve low-pass or band-pass filtering functionality % sig: input signal to be filtered % fmin: lower cutoff frequency (when fmin=0, implements low-pass filter; when fmin>0, implements band-pass filter) % fmax: upper cutoff frequency (must satisfy fmax > fmin) % fs: sampling frequency of the input signal % y: filtered output signal