A novel two-stage nonrecursive architecture for the design of generalized comb filters
This paper presents a novel two-stage class of decimation filters with superior spurious signal rejection performance around the so-called folding bands, i.e., frequency intervals whose signals get folded down to baseband due to decimation. The key idea to enhance signal rejection in the frequency domain lies on an effective way to place the zeros of a classical comb filter in the aforementioned folding bands. On the other hand, the paper provides a mathematical framework for designing two-stage multiplierless and nonrecursive structures of the proposed filters. Examples are provided to highlight the key steps in the design of the proposed filters. Moreover, the frequency behavior of the proposed filters in both baseband and stopband is compared with classical and generalized comb filters, and a droop compensator is proposed to counteract the passband distortion of the proposed filters.
generalized comb filters comb decimation decimation filter a/d converter cic filter