ELA, Volume 10, pp. 240-256, November 2003, abstract.

J-Spectral Factorization for Rational Matrix 
Functions with Alternative Realization
by
Gilbert J. Groenewald and Mark A. Petersen

In this paper, recent results by Petersen and Ran on 
the J-spectral factorization problem to rational matrix 
functions with constant signature that are not necessarily 
analytic at infinity are extended. In particular, a full 
parametrization of all \tilde{J}-spectral factors that have 
the same pole pair as a given square J-spectral factor is 
given. In this case a special realization involving a quintet 
of matrices is used.