Efficient multistage comb-modified rotated sinc (RS) decimator

This paper presents a new multistage comb-rotated sinc (RS) decimator. The proposed structure consists of different cascaded comb sections, each down-sampled by a specific down-sampling factor. The number of sections depends on the decimation factor of the original comb decimator. The first section is realized in a non-recursive form. Using the polyphase decomposition, the sub-filters of the first section can be operated at lower rate which depends on the down-sampling factor of the first section. Additionally, the rotated sinc (RS) filter is cascaded in the second section, thus permitting both multipliers of the RS filter to work at the lower rate. The magnitude response of the proposed structure is better than that of the original comb decimator.