Design of multiplierless linear-phase comb corrector filters for multirate applications

This paper presents an efficient design of comb-based decimation filters extensively used in the first stage of multistage decimation architectures. The contribution of this work is the introduction of a multiplierless Finite Impulse Response (FIR) low-order linear-phase corrector filter to decrease the passband droop while simultaneously improving the attenuation of classical comb filters in the so-called folding bands. Upon using polyphase decomposition, the proposed filters can be operated at a lower rate. The resulting filters feature compensated passband droop and higher folding-band attenuation than traditional comb filters, while require only shift-and-add operations. Comparisons with other architectures in literature are provided to emphasize the main features along with the key design steps of the proposed filters.