US 2018/0159510 A1 · SPARSE CASCADED-INTEGRATOR-COMB FILTERS

Abstract

In a cascaded integrator comb (CIC) filter, a time-varying gain is added before the last integrating stage transforming its sub optimal boxcar impulse response into an FIR filter of arbitrary length. Make the coefficients sparse and taking them from a set of small integers leads to an efficient hardware implementation that does not compromise any of the essential CIC filter characteristics especially the overflow handling. The proposed sparse CIC structure can improve the worst case stop band attenuation by as much as 10 dB while occupying 77% of the chip area and consuming 30% less power compared to a standard a 5th order CIC filter, and reducing the overall bit growth of the filter and the amount of high rate operations. Design examples are given illustrating the advantages and flexibility of the proposed structure.

Claims20

Dependent claims

A sparse cascaded-integrator-comb (CIC) filter comprising:

an integrator operating on signal values sampled at a sampling rate corresponding a clock rate fs;
a finite impulse response (FIR) filter;
a multiplier arranged at an input of the FIR filter and sequentially receiving time-varying sparse filter coefficients and multiplying each of the sequentially received time-varying filter coefficients with a corresponding one of the sampled signal values received from the integrator;
a decimation stage reducing the sampling rate by a predetermined decimation ratio N;
and
a differentiator operating at a clock rate of fs/N and providing filtered decimated output values.

3 more elements

Dependencies are inferred from the claim text.

Sparse cascaded-integrator-comb filters

Life of this patent

Sparse cascaded-integrator-comb filters

Life of this patent

Abstract

Claims20