Stepped Triangular CIC-Cosine Decimation Filter

This paper presents a new two-stage CIC-cosine decimation filter. The original CIC filter is replaced by a two-stage CIC structure where the first section is realized in a nonrecursive form, and the second section is a CIC filter which works at lower rate that depends on the decimation factor of the first stage. Using the polyphase decomposition, the subfilters of the first section can also be operated at a lower rate. The magnitude response of this filter is improved by using cosine prefilters which can also be moved to operate at a lower rate. Consequently, the resulting structure does not have any filtering at the high input rate, is multiplier-free, and has an improved magnitude characteristic compared to that of the original CIC filter