Yet another H/sup /spl infin// discretization

A new approach to the conversion of the sampled-data H/sup /spl infin// problem to an equivalent pure discrete-time, lumped-variables counterpart, is presented. The approach is independent of controller causality constraints. In particular, it is applicable to problems, such as preview tracking and fixed-lag smoothing, where existing reduction methods fail. We demonstrate this by presenting a way to solve the open problem no. 51 from the book Open Problems in Mathematical Systems and Control Theory.