Design of space-efficient, wide- and narrow transition-band, FIR filters

We propose a method for designing a filter to meet a set of specifications, which can be implemented with reduced area. Our approach combines a prefilter implementation structure whose function has been developed over the years with our previously reported variable precision technique for intelligently quantizing the filter coefficients. Our area-efficient structure uses frequency masking with a single filter model to give good performance with low order and low coefficient sensitivity. Our method does use a novel connection of a simple prefilter structure used in a frequency masking technique to give good designs for the previously unattainable wide-band filter designs. The technique also gives designs with superior (very sharp) transition regions. Both types produce filters that efficiently use digital circuitry, leading to space-efficient designs that are significantly smaller than would otherwise be the case. Some examples are given to demonstrate the effectiveness of our design.