scipy.signal.

symiirorder2#

scipy.signal.symiirorder2(input, r, omega, precision=-1.0)[source]#

Implement a smoothing IIR filter with mirror-symmetric boundary conditions using a cascade of second-order sections.

The second section uses a reversed sequence. This implements the following transfer function:

                         cs^2
H(z) = ---------------------------------------
       (1 - a2/z - a3/z^2) (1 - a2 z - a3 z^2 )

where:

a2 = 2 * r * cos(omega)
a3 = - r ** 2
cs = 1 - 2 * r * cos(omega) + r ** 2

Parameters:

inputndarray: The input signal.
r, omegafloat: Parameters in the transfer function.
precisionfloat: Specifies the precision for calculating initial conditions of the recursive filter based on mirror-symmetric input.

Returns:

outputndarray: The filtered signal.

Notes

Array API Standard Support

symiirorder2 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.