Calculate a FIR filter. N is the half size of the filter, so the resulting filter will have 2N+1 points. OmegaP is the end of the pass band, the ripple in the pass band is weighted with Wp. OmegaS is the beginning of the stop band, the stop band is weighted with Ws. Data npts just controls the number of points to create the FFT for display, it does not effect the filter.