# scipy.signal.lp2hp_zpk

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

  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.

  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.

  See also

  `lp2lp_zpk`, `lp2bp_zpk`, `lp2bs_zpk`, `bilinear`
  `lp2hp`

  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.

scipy.signal.lp2hp scipy.signal.lp2lp