# scipy.signal.sos2zpk

scipy.signal.sos2zpk(sos)

  Return zeros, poles, and gain of a series of second-order sections

  Parameters:
    sos array_like

      Array of second-order filter coefficients, must have shape `(n_sections, 6)`. See `sosfilt` for the SOS filter format specification.

  Returns:
    z ndarray

      Zeros of the transfer function.

    p ndarray

      Poles of the transfer function.

    k float

      System gain.

  Notes

  The number of zeros and poles returned will be `n_sections * 2` even if some of these are (effectively) zero.

  New in version 0.16.0.