Spectral factorization and quarter-plane digital filters
J. Murray · IEEE Transactions on Circuits and Systems · 1978
Two sets of necessary conditions are derived for the existence of a rational spectral factorization of a given rational function of two complex variables: partial converses of these results are given, and the implications of these conditions for the design of minimum-phase FIR filters and stable IIR filters are discussed. In particular, it is shown that these conditions are closely related to the difficulties encountered in the stabilization problem for two-dimensional IIR filters.