Efficient multiplierless implementation of FIR filters of variable bandwidth and sharp transition using a prefilter-equalizer cascade structure

We develop a multiplierless implementation structure with significant area reduction for FIR filters with arbitrary bandwidth. A 2 stage prefilter-equalizer structure is used to reduce implementation complexity while achieving high stopband attenuation and a sharp transition band. Other prefilter-equalizer approaches typically focus only on the narrow band filter design, however our approach allows filters with arbitrary bandwidth to be realized with simple complexity. Our prefilter provides good stopband attenuation and a sharp transition band through frequency masking. Our approach for the second level is targeted at reducing the complexity of the equalizer required. We apply variable precision coefficient techniques to further reduce the complexity of the circuit. We provide a systematic design procedure that can be used to create efficient cascading FIR filters which is illustrated by narrow-band and wide-band examples.