On the design of sharp cutoff wide-band FIR filters with reduced arithmetic complexity

The authors provide an approximate analytical characterization for wideband low-pass filters using the frequency masking approach introduced by Y.C. Lim (ibid., vol.CAS-33, no.4, p.357-64, Apr. 1968). They extend this realization to the case of wideband bandpass filters. Approximate expressions of the optimal value of the interpolating factor L are derived that minimize the total arithmetic hardware used in the overall realization. Expressions for the number of adders and multipliers required are also derived. The proposed two-branch realization is computationally more efficient than that conventional direct-form realization, with a moderate increase in the number of delays. The noise performance of these wideband designs compares very favorably with those of equivalent direct-form realizations. >