SciPy

scipy.signal.symiirorder1

scipy.signal.symiirorder1(input, c0, z1 {, precision}) → output

Implement a smoothing IIR filter with mirror-symmetric boundary conditions using a cascade of first-order sections. The second section uses a reversed sequence. This implements a system with the following transfer function and mirror-symmetric boundary conditions:

                c0              
H(z) = ---------------------    
        (1-z1/z) (1 - z1 z)     

The resulting signal will have mirror symmetric boundary conditions as well.

Parameters :

input : ndarray

The input signal.

c0, z1 : scalar

Parameters in the transfer function.

precision : :

Specifies the precision for calculating initial conditions of the recursive filter based on mirror-symmetric input.

Returns :

output : ndarray

The filtered signal.