NGMV Control Toolbox

S-domain polynomial spectral factorization.

Syntax

• A = SPFC(B)

  A = SPFC(B,'method')

  A = SPFC(B,'method',TOL)

  [A,ERR] = SPFC(...)

Description

This routine solves the polynomial spectral factorization problem in S-domain:

where B is a given hermitian polynomial positive on the imaginary axis and A is a stable polynomial.

The string 'method' specifies one of the following algorithms:

'def'              -- based on the factorization of B and selection of stable factors. This is the default method.

'gauss2'        -- numerical method based on solving a linear polynomial equation (2^nd order)

'gauss3'        -- numerical method based on solving a linear polynomial equation (3^rd order)

Note: the routine works even when B has roots on the imaginary axis.

The tolerance TOL can be specified as an additional argument. Its default value is TOL = 10*eps.

The error of the solution can be returned in ERR.

.See Also

spfz

spf2

spfz