scipy.signal.

ellipap

scipy.signal.ellipap(N, rp, rs, *, xp=None, device=None)

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.

Parameters:

Nint

The order of the filter

rpfloat

The passband ripple intensity

rsfloat

The stopband attenuation

xparray_namespace, optional

Optional array namespace. Should be compatible with the array API standard, or supported by array-api-compat. Default: numpy

device: any

optional device specification for output. Should match one of the supported device specification in xp.

Returns:

z, p, k

Poles, zeros and gain for the filter prototype

See also

ellip

Filter design function using this prototype

References

[1]

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

[2]

Orfanidis, “Lecture Notes on Elliptic Filter Design”, https://www.ece.rutgers.edu/~orfanidi/ece521/notes.pdf