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.

References

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