Properties of linear switching time-varying discrete-time systems with applications

We study two discrete-time, linear switching time-varying (LSTV) structures , each of which consists of a periodic switch connected to several linear t ime-invariant (LTI) systems. Such structures can be used to represent any l inear periodically time-varying (LPTV) systems. We give basic properties as sociated with the LSTV structures in terms of their LTI building blocks, an d then apply the results to solve a general approximation problem: How to o ptimally approximate an LPTV system with period p by an LPTV system with pe riod (p) over cap? The optimality is measured using H-2 norms. The study is extended to general multirate periodic systems. (C) 2000 Elsevier Science B.V. All rights reserved.