scipy.signal.

buttap#

scipy.signal.buttap(N, *, xp=None, device=None)[source]#

Return (z,p,k) for analog prototype of Nth-order Butterworth filter.

The filter will have an angular (e.g., rad/s) cutoff frequency of 1.

Parameters:

Nint: The order of the filter
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:

zndarray[float64]: Zeros of the transfer function. Is always an empty array.
pndarray[complex128]: Poles of the transfer function.
kfloat: Gain of the transfer function.

See also

butter: Filter design function using this prototype

Notes

Array API Standard Support

buttap has experimental support for Python Array API Standard compatible backends in addition to NumPy. Please consider testing these features by setting an environment variable SCIPY_ARRAY_API=1 and providing CuPy, PyTorch, JAX, or Dask arrays as array arguments. The following combinations of backend and device (or other capability) are supported.

Library	CPU	GPU
NumPy	✅	n/a
CuPy	n/a	✅
PyTorch	✅	✅
JAX	✅	✅
Dask	✅	n/a

See Support for the array API standard for more information.