Polyphase representation of multirate Volterra filters

Abstract

This paper proposes a polyphase representation for Volterra filters. To derive the new realizations the well known linear polyphase theory is extended to the nonlinear case starting with Volterra filters. Both the upsampling and downsampling case are considered. As in the linear case (FIR filters) neither the input signal nor the Volterra kernels must fulfill constraints in order to be realized in polyphase form. The computational complexity could be reduced significantly because of two reasons. On the one hand all operations are performed at the low sampling rate and on the other hand some coefficients disappear in the polyphase representation.