`scipy.signal._filter_design:lp2hp_zpk`

source: build-install/usr/lib/python3.14/site-packages/scipy/signal/_filter_design.py:3115

Signature

def lp2hp_zpk(z, p, k, wo = 1.0)

Summary

Transform a lowpass filter prototype to a highpass filter.

Extended Summary

Return an analog high-pass filter with cutoff frequency wo from an analog low-pass filter prototype with unity cutoff frequency, using zeros, poles, and gain ('zpk') representation.

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.
wo : float: Desired cutoff, as angular frequency (e.g., rad/s). Defaults to no change.

Returns

z : ndarray: Zeros of the transformed high-pass filter transfer function.
p : ndarray: Poles of the transformed high-pass filter transfer function.
k : float: System gain of the transformed high-pass filter.

Notes

This is derived from the s-plane substitution

s \to \frac{ω _{0}}{s}

This maintains symmetry of the lowpass and highpass responses on a logarithmic scale.

Examples

Use the 'zpk' (Zero-Pole-Gain) representation of a lowpass filter to transform it to a highpass filter with a cutoff frequency wo.

from scipy.signal import lp2hp_zpk
z   = [ -2 + 3j ,  -0.5 - 0.8j ]
p   = [ -1      ,  -4          ]
k   = 10
wo  = 0.6

✓

lp2hp_zpk(z, p, k, wo)

✗

(array([-0.09230769-0.13846154j, -0.33707865+0.53932584j]), array([-0.6 , -0.15]), np.float64(8.5))

`scipy.signal._filter_design:lp2hp_zpk`

Signature

Summary

Extended Summary

Parameters

Returns

Notes

Examples

See also

Aliases

Referenced by

This package