基于多相结构和部分锐化的CIC抽取滤波器

该文将传统的CIC(Cascaded Integrator Comb)滤波器传递函数分解为递归和非递归部分，可独立调整两者的级联因子；对递归部分进行尖锐化处理改善滤波器的通带衰落，利用电路的等价交换性将抽取因子提前使其工作在低采样率；对非递归部分进行多相分解，实现高速滤波。计算机仿真表明:与传统的CIC、锐化CIC滤波器相比，改进的CIC具有好的通阻带特性；并从通带衰落和混叠抑制的角度，分析了递归和非递归部分的级联因子的取值对整个改进的CIC滤波器特性的影响。

CIC Decimation Filters Based on Polyphase Structure and Partially Sharpening Technique

In this paper an improved solution to the design of Cascaded-Integrator-Comb (CIC) filter is proposed, in which the overall transfer function is factorized to recursive and non-recursive parts. The cascade factors of two parts can be adjusted independently. The sharpening is applied to recursive part to correct the passband droop, and decimation factor is moved prior to the sharpening of recursive part by the use of equivalent transform to operate at a low rate. Polyphase decomposition is applied to non-recursive part to realize high-speed filtering. Computer simulation shows that the modified CIC filter has a frequency response comparable to that of sharpening CIC filters while design flexibility is increased. The effect of the cascade factor of recursive and non-recursive parts on the modified CIC frequency response is discussed in terms of passband droop and alias rejection.