Equiripple-Stopband Multiplierless FIR Filters by Chebyshev Sharpening of Two-Sample Averaging

Odd-length linear-phase prototype FIR filters were recently sharpened with scaled Chebyshev polynomials. Here the approach is extended to even-length prototypes and applied to a two-tap averaging filter, and passband normalization in either case is greatly improved for wide-stopband designs. This paper also presents an alternate sharpened-filter structure suitable for decimation or interpolation filtering or for antenna-array weighting. Either structure can generally be made multiplierless.