Simple multiplierless CIC compensators providing minimum passband deviation

Abstract

A simple multiplierless decimation filter is cascaded-integrator-comb (CIC) filter. However, the CIC filter offering high folding-band attenuations introduces a high passband droop. The most popular technique for reducing the droop is connecting a low-order FIR filter called compensator in cascade with CIC filter. In this paper, we present a method for the design of simple multiplierless compensators based on the minimization of the peak-to-peak passband deviation. We form a simple design problem by representing each compensator coefficient as only one signed power of two. The optimum coefficients are found by using the exhaustive search. We show that the proposed compensators with three and five coefficients significantly reduce the droop in wide passbands despite their extremely simple structures, which contain only two and four adders, respectively.