scipy.signal.bilinear_zpk

scipy.signal.bilinear_zpk(z, p, k, fs)

Return a digital IIR filter from an analog one using a bilinear transform.

Transform a set of poles and zeros from the analog s-plane to the digital z-plane using Tustin’s method, which substitutes (z-1) / (z+1) for s, maintaining the shape of the frequency response.

Parameters:

z : array_like

Zeros of the analog filter transfer function.

p : array_like

Poles of the analog filter transfer function.

k : float

System gain of the analog filter transfer function.

fs : float

Sample rate, as ordinary frequency (e.g. hertz). No prewarping is done in this function.

Returns:

z : ndarray

Zeros of the transformed digital filter transfer function.

p : ndarray

Poles of the transformed digital filter transfer function.

k : float

System gain of the transformed digital filter.

See also

lp2lp_zpk, lp2hp_zpk, lp2bp_zpk, lp2bs_zpk, bilinear

Notes

New in version 1.1.0.