Almost distortion-free IIR subband filters using a nested structure

In this paper almost-perfect reconstruction techniques for m-channel multirate systems are investigated. It is shown here that using two allpass filters it is possible to generate a three channel filter bank that eliminates various errors caused by the analysis/synthesis system. In particular, a technique to cancel alias and magnitude distortion is outlined here. It is also shown that the classical two channel synthesis filter is a special case of the proposed synthesis filter bank selection procedure. Illustrative example and design algorithms are included to supplement the theory