How do I use remez to make a differentiator?
The remez function can also design a differentiating filter. In this case, the filter has one band, and the band’s magnitude is zero at DC, and climbs linearly to pi*Fs at the Nyquist frequency. By specifying the string ‘differentiator’ as an optional fourth argument, remez will give the filter odd phase and relatively weight the filter as a function of frequency, so the filter is more accurate where its magnitude is small and less accurate where its magnitude is large.
