Optimal Equiripple Comb FIR Filters

P. Zahradník and M. Vlček (Czech Republic)


FIR, comb filter, narrow band, optimal filter, equiripple ap proximation, analytical design, recursive algorithm.


A novel analytical design method for highly selective dig ital optimal equiripple comb FIR filters is presented. The equiripple comb FIR filters are optimal in the Chebyshev sense. The number of notch bands, the width of the notch bands and the attenuation in the passbands can be indepen dently specified. The degree formula and the differential equation for the generating polynomial of the filter is pre sented. Based on the differential equation, a fast simple algebraic recursive procedure for the evaluation of the im pulse response of the filter is described. Its arithmetic ro bustness outperforms by far the known analytical design method. Highly selective equiripple comb FIR filters with thousands of coefficients can be designed. One example demonstrates the efficiency of the filter design.

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