Single Filter Frequency Masking High-Speed Recursive Digital Filters

For recursive filter the maximal sample frequency is bounded by the recursiveloops in the filter. [In this paper, it is understood that recursive filters are infinite-length impulse response (IIR)filters.] In this work, a filter structure based on the use of the frequency maskingapproach is presented that increases the maximal sample frequency for narrowband andwideband filters by introducing more delay elements in the recursive loops. By usingidentical subfilters (except for the periods), the subfilters can be mapped using foldingto a single pipeline/interleaved arithmetic structure yielding an area-efficient implementation.The filters are potentially suitable for low-power implementation by using powersupply voltage scaling techniques. In this work, the design of the filters is discussed andestimations of the ripples are derived. Two examples show the viability of the proposedmethod.