T. Bose et al., STABILITY OF 2-DIMENSIONAL DISCRETE-SYSTEMS WITH PERIODIC COEFFICIENTS, IEEE transactions on circuits and systems. 2, Analog and digital signal processing, 45(7), 1998, pp. 839-847
Two-dimensional (2-D) discrete systems with periodic coefficients are
considered for stability. These systems are called periodically shift
variant (PSV) digital filters and have many applications in signal pro
cessing that include the filtering of 2-D signals with cyclostationary
noise, scrambling of digital images, and implementation of multirate
filter banks. In this paper, the filters are formulated in the form of
the well known Fornasini-Marchesini state-space model with periodic c
oefficients. This PSV model is then studied for stability. Two suffici
ent conditions and one necessary condition are established for asympto
tic stability. Some examples are given to illustrate the results.