# scipy.signal.lp2hp_zpk¶

scipy.signal.lp2hp_zpk(z, p, k, wo=1.0)[source]

Transform a lowpass filter prototype to a highpass filter.

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. 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

$s \rightarrow \frac{\omega_0}{s}$

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

New in version 1.1.0.

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