Improved Two-Stage Decimator Structure Using Kaiser Hamming Sharpening

Abstract

In this paper, we propose an efficient two-stage decimator structure based on Kaiser Hamming sharpening (KHS) of moving average filter. The proposed KHS decimator divides the overall decimation factor $$M = M_1M_2$$ , such that both $$M_1, M_2 \in {\mathbb {Z}}^+$$ . The first stage uses KHS with first and second order of tangency at unity and zero, respectively. The second stage uses the simplest KHS sharpening, i.e. first-order tangency at both unity and zero. The architecture of the proposed structure is designed to match the existing decimator to have nearly equal number of integrator sections operating at high sampling frequency of $$f_\mathrm{s}$$ . The pass-band droop at the normalized pass-band cut-off frequency of 1/2M in the proposed design is $$13.8\%$$ less as compared to the existing KHS decimator, with a compromise of $$3\%$$ in alias rejection. Further, as the normalized pass-band cut-off frequency is reduced to 1/4M, the proposed design in comparison to existing decimator has $$34.5\%$$ less droop with only $$2.3\%$$ compromise in alias rejection.