In this paper we present two-stage CIC (cascaded-integrator-comb) decimation filters with decimation factor M expressed as M = M₁M₂, where $M_1,M_2\in {\mathbb{Z}}^{+}$. The proposed decimator-I aims to minimize the pass-band droop using a cascade connection of Kaiser Hamming (KH) and Saramäki-Ritoniemi (SR) sharpening structures. The coefficients of second stage are determined using linear programming in MATLAB. The proposed CIC decimator-I when designed for various integer decimation factors on an average has a pass-band droop of −0.09 dB at the normalized frequency of 1/2 M and an average alias rejection of −44 dB at the normalized frequency of 3/2 M. Further, another decimator-II structure extends decimator-I to achieve an alias rejection of −87 dB and pass-band droop of −0.17 dB. The FPGA implementation of proposed designs has lower slice utilization and achieves higher maximum operating frequency than other existing competing designs. The performance of proposed decimation filters is confirmed using computer simulations in analog-to-digital converters (ADC) and sigma-delta (ΣΔ) modulators.

在本文中，我们提出了两级CIC（级联积分梳状）抽取滤波器，抽取因子M表示为M  =  M ₁ M ₂，其中${\mathrm{中号}}_{\mathrm{1个}}，{\mathrm{中号}}_{\mathrm{2个}}\in {\mathbb{ž}}^{+}$。拟议的抽取器I旨在通过使用Kaiser Hamming（KH）和Saramäki-Ritoniemi（SR）锐化结构的级联来最大程度地减小通带下垂。第二阶段的系数是使用MATLAB中的线性编程确定的。当针对各种整数抽取因子设计时，建议的CIC抽取器I平均在1/2 M的归一化频率下具有-0.09 dB的通带下降，在3的归一化频率下具有-44 dB的平均混叠抑制/ 2M。此外，另一种抽取器-II结构扩展了抽取器-I，以实现-87 dB的混叠抑制和-0.17 dB的通带下垂。与其他现有竞争设计相比，拟议设计的FPGA实现具有更低的切片利用率，并实现了更高的最大工作频率。