Comb-based Method for Narrowband Fir Filter Design

FIR (Finite impulse response) digital filters are known to have some very desirable properties such as linear phase, stability, and absence of limit cycle. However their applications generally require more computation. In this paper we consider the simple method to design a multiplier-less narrowband FIR filter. The method is based on well known IFIR (Interpolated FIR) structure. The novelty of the proposed approach is the new structure, where the interpolation filter is the cascade of comb filters and the wideband compensators. The comb filters and compensators are multiplier-less filters. The model filter is rounded to the nearest integers, which can be implemented with the adders and shifts. Consequently, the overall structure exhibits a low complexity and does not require the multipliers.