Stepped triangular CIC decimation filter for SDR applications

This paper presents a new two-stage CIC decimation filter. The original CIC filter is replaced by a two-stage CIC structure where both sections are realized in a nonrecursive form. Using the polyphase decomposition, the subfilters of both sections are operated at a lower rate resulting in a fast and a low power structure. The magnitude response of this filter is improved by using the stepped-triangular impulse response filter and one simple compensation filter which works at the low rate. Consequently, the resulting structure does not have any filtering at the high input rate, and has an improved magnitude characteristic compared to that of the original CIC filter. Additionally the proposed filter is multiplierless. As a result the proposed decimation filter can be useful for SDR (Software defined radio) applications.