Comb-based decimator for SDR applications

This paper presents a novel comb-based decimator for the SDR (Software Defined Radio) applications. The expanded cosine filters and the expanded multiplierless compensators are cascaded with the comb filter. The comb filter is realized in a nonrecursive form. We consider the case where the decimation factor M is the power of two, i.e M=2^k. In that way we have k+1-stage structure, where the first k stages are the cosine filters followed by the downsampling by two, and the last stage is the cascade of simple compensators. The proposed structure has much better magnitude characteristic than the corresponding comb filter.