This function computes the group delay of a filter.
gd = grpdelay(b) gd = grpdelay(b, a) gd = grpdelay(b, a, nfft) gd = grpdelay(b, a, nfft, whole) gd = grpdelay(b, a, nfft, whole, Fs) [gd, w] = grpdelay(...)