Efficient design of two-stage comb-based decimation filters using Chebyshev sharpening

A simple and efficient method to design multiplierless two-stage comb-based decimation filters is presented. The proposed scheme takes advantage of the Chebyshev sharpening, recently introduced in literature, to obtain higher selectivity in comparison to traditional comb filters. The resulting filter has better magnitude response characteristics and fewer Additions Per Output Sample (APOS) with respect to other two-stage comb-based filters available in literature.