An Economical Class of Droop-Compensated Generalized Comb Filters: Analysis and Design

In this brief, we address the design of economical recursive generalized comb filters (GCFs) by proposing an efficient technique to quantize the multipliers in the
z
-transfer function employing power-of-2 (PO2) terms. GCFs are efficient anti-aliasing decimation filters with improved selectivity and quantization noise rejection performance around the so-called folding bands with respect to classical comb filters. The proposed quantization technique guarantees perfect pole-zero cancelation in the rational
z
-transfer function of the GCFs, thus totally avoiding instability problems. Moreover, we propose the use of a simple droop compensator for the sake of recovering the passband droop distorting the useful digital signal in the baseband. A design example is proposed with the aim of showing the application of the proposed technique, and a practical architecture of a sample third-order GCF is discussed.