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# scipy.signal.ellipap

`scipy.signal.``ellipap`(N, rp, rs)

  Return (z,p,k) of Nth-order elliptic analog lowpass filter.

  The filter is a normalized prototype that has rp decibels of ripple in the passband and a stopband rs decibels down.

  The filter’s angular (e.g. rad/s) cutoff frequency is normalized to 1, defined as the point at which the gain first drops below `-rp`.

  See also

  `ellip`
    Filter design function using this prototype

  References

  [R215] | Lutova, Tosic, and Evans, “Filter Design for Signal Processing”, Chapters 5 and 12.