多级锐化的梳状抽取滤波器

Multistage sharpened comb decimation filter

针对传统的递归型级联积分-梳状抽取滤波器(CICDF)频响特性不理想、功耗较大、最大电路速率受限等问题,提出了一种多级锐化的梳状抽取滤波器(MSCDF)。该滤波器利用降序素数分解和部分多相分解相结合的方法将CICDF转化为多级多相结构以降低功耗和放宽对电路速率的限制,并从第二级开始逐级进行锐化处理从而使抽取器的频响得到改善。仿真结果表明,在抽取因子为非素数的情况下,MSCDF不仅能够有效地改善CICDF的通带衰减和混叠抑制性能,而且与频响相近的完全锐化抽取器(FSCDF)相比,功耗更小,最大电路速率更高。

In consideration of the problems in traditional recursive cascaded integrator-comb decimation filters （CICDF）, such as unacceptable frequency response, high power consumption and restricted circuit speed, the paper proposes a novel multistage sharpened comb decimation filter （MSCDF）. To lower the power consumption and loosen the limitation of cir- cuit speed, the MSCDF converts the CICDF into a multistage polyphase structure using descending prime factorization and partial polyphase decomposition, and starts the sharpening process from the second stage for improvement of the frequency response. The simulation results indicate that, when the decimation ratio is not prime, the MSCDF can effectively improve the passband droop and aliasing rejection of the CICDF, and compared with the full-sharpened comb decimation filter （FSCDF） which has the similar frequency response, it can lower the power consumption and higher maximum circuit speed.