频响改善的低功耗CIC抽取滤波器

摘要

针对传统递归型CIC(cascaded-integrated comb filters)抽取滤波器功耗较大、频率响应特性不理想的缺陷,设计了一种改进的非递归型CIC抽取滤波器.利用降序素数分解和多相分解使CIC滤波器以多级多相的低功耗结构实现,通过适当增大级联因子提高抽取器的混叠抑制比,同时利用一个2阶的SIN型补偿滤波器有效地减小通带衰减.仿真结果表明,与其他方案相比,改进的抽取滤波器能够在较低功耗条件下,获得理想的通带衰减和混叠抑制性能.%A modified non-recursive CIC decimation filter was designed in order to lower the power consumption and improve the frequency response of the traditional recursive CIC decimator.Making use of the descending prime factorization and polyphase decomposition, the CIC decimation filter was transformed into a multistage polyphase structure with lower power consumption.The aliasing rejection could be improved by properly increasing the cascading order, and the corresponding passband droop was effectively compensated by a 2nd order Sin-based filter.Simulation results demonstrate that, compared with other schemes, the new decimator can get acceptable passband droop and aliasing rejection with lower power consumption.