scipy.signal.

sos2tf#

scipy.signal.sos2tf(sos)[source]#

Return a single transfer function from a series of second-order sections

Parameters:

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

Returns:

bndarray: Numerator polynomial coefficients.
andarray: Denominator polynomial coefficients.

Notes

Added in version 0.16.0.

Array API Standard Support

sos2tf 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	⚠️ no JIT	⛔
Dask	⚠️ computes graph	n/a

See Support for the array API standard for more information.

Examples

Find the polynomial representation of an elliptic filter using its ‘sos’ (second-order sections) format.

>>> from scipy.signal import sos2tf
>>> from scipy import signal
>>> sos = signal.ellip(1, 0.001, 50, 0.1, output='sos')
>>> sos2tf(sos)
(   array([0.91256522, 0.91256522, 0.        ]),
    array([1.        , 0.82513043, 0.        ]))