Narrow-band and wide-band high-speed recursive digital filters using single filter frequency masking techniques

In this paper the design of single filter frequency masking recursive filters is discussed. We briefly review the previously proposed lowpass narrow-band filters and propose a design method for highpass narrow-band filters. Wide-band filters are also discussed. The proposed approach uses several identical filters, except for periodicity, which are mapped to a single hardware structure using folding. This results in an area-efficient, pipeline/interleaved implementation with a small number of multipliers and adders at the cost of more registers. The resulting structure has a higher maximal sample frequency compared with a direct implementation of the filter, and is therefore potentially more suitable for a low-power implementation by supply voltage scaling. An example illustrates the design of a wide-band lowpass filter.