A High Speed Digital Decimation Filter with Parallel Cascaded Integrator-Comb Pre-Filters

Parallel cascaded integrator-comb (CIC) pre-filters are proposed to greatly increase the speed of digital decimation filters. Several times of clock rate improvement can be achieved by paralleling computations. Unlike traditional poly-phase parallel decomposition, the new method avoids the substantial area/complexity increase, as a consequence of converting to parallel structure, by exploiting the simple and effective recursive filtering of the CIC pre-filters. With these two methods combined, the new filter achieves unprecedented clock rate and considerable area/complexity savings while providing frequency response similar to those of traditional decimation filters.