Design of Comb Decimation Filter with Improved Aliasing Rejection and Compensated Passband

A simple design of a multiplierless comb decimation filter with an improved aliasing rejection and a compensated passband is presented in this paper. The aliasing rejection in the comb folding bands is improved by cascading simple multiplierless comb-based filters, with a comb filter. The simple filters introduce the additional zeros into comb folding bands, thus increasing the widths and the attenuation in the folding bands. It is interesting that the passband droop in the proposed filter and in the equivalent comb filter, are equal. As a consequence, the compensators for comb filters, proposed in literature, may be used. The method is illustrated with examples. The comparisons, with the methods from literature, are provided to show the benefit of the proposed method.