cupyx.scipy.signal.cheby2#

cupyx.scipy.signal.cheby2(N, rs, Wn, btype='low', analog=False, output='ba', fs=None)[source]#

Chebyshev type II digital and analog filter design.

Design an Nth-order digital or analog Chebyshev type II filter and return the filter coefficients.

Parameters:

N (int) – The order of the filter.
rs (float) – The minimum attenuation required in the stop band. Specified in decibels, as a positive number.
Wn (array_like) –
A scalar or length-2 sequence giving the critical frequencies. For Type II filters, this is the point in the transition band at which the gain first reaches -rs.

For digital filters, Wn are in the same units as fs. By default, fs is 2 half-cycles/sample, so these are normalized from 0 to 1, where 1 is the Nyquist frequency. (Wn is thus in half-cycles / sample.)

For analog filters, Wn is an angular frequency (e.g., rad/s).
btype ({'lowpass', 'highpass', 'bandpass', 'bandstop'}, optional) – The type of filter. Default is ‘lowpass’.
analog (bool, optional) – When True, return an analog filter, otherwise a digital filter is returned.
output ({'ba', 'zpk', 'sos'}, optional) – Type of output: numerator/denominator (‘ba’), pole-zero (‘zpk’), or second-order sections (‘sos’). Default is ‘ba’ for backwards compatibility, but ‘sos’ should be used for general-purpose filtering.
fs (float, optional) – The sampling frequency of the digital system.

Returns:

b, a (ndarray, ndarray) – Numerator (b) and denominator (a) polynomials of the IIR filter. Only returned if output='ba'.
z, p, k (ndarray, ndarray, float) – Zeros, poles, and system gain of the IIR filter transfer function. Only returned if output='zpk'.
sos (ndarray) – Second-order sections representation of the IIR filter. Only returned if output='sos'.