High-decimation digital filters

Abstract

The architecture of an efficient high-decimation rate filter is presented. A high-decimation rate filter can extract narrowband signal intelligence from a wideband signal. As a result, it is important to many signal processing applications found in communications and instrumentation. The presented high-decimation rate filter is a multi-rate system consisting of a cascaded integrator-comb (CIC) section and a finite impulse response (FIR) filter. The function of the CIC section is to perform efficient high-decimation filtering over the entire frequency band. The function of the FIR filter is to achieve prespecified transition band performance at baseband. The authors investigate the CMOS implementation of a 33 MHz high-decimation rate filter, its hardware implementation, and its performance. Examples of its use are also provided.