This note is concerned with the H-infinity deconvolution filtering problem for linear time-varying discretetime systems described by state space models.The H-infinity deconvolution filter is derived by proposing a new approach in Krein space.With the new approach,it is clearly shown that the central deconvolution filter in an H-infinity setting is the same as the one in an H2 setting associated with one constructed stochastic state-space model.This insight allows us to calculate the complicated H-infinity deconvolution filter in an intuitive and simple way.The deconvolution filter is calculated by performing Riccati equation with the same order as that of the original system.
