scipy.signal.cheb2ord

scipy.signal.cheb2ord(wp, ws, gpass, gstop, analog=0)

Chebyshev type II filter order selection.

Description:

Return the order of the lowest order digital Chebyshev Type II filter that loses no more than gpass dB in the passband and has at least gstop dB attenuation in the stopband.

Parameters:

wp, ws – Passband and stopband edge frequencies, normalized from 0 :

to 1 (1 corresponds to pi radians / sample). For example:

Lowpass: wp = 0.2, ws = 0.3 Highpass: wp = 0.3, ws = 0.2 Bandpass: wp = [0.2, 0.5], ws = [0.1, 0.6] Bandstop: wp = [0.1, 0.6], ws = [0.2, 0.5]

gpass – The maximum loss in the passband (dB). :

gstop – The minimum attenuation in the stopband (dB). :

analog – Non-zero to design an analog filter (in this case wp and :

ws are in radians / second).

Returns:

ord – The lowest order for a Chebyshev type II filter that meets specs. :

Wn – The Chebyshev natural frequency for :

use with scipy.signal.cheby2 to give the filter.