可编程多级级联积分梳状内插滤波器的设计

Design of a Programmable Multi-Stage Cascade Integrating Comb Interpolation Filter

从原理上分析了级联积分梳状滤波器(CIC滤波器)的特点,及主要参数对滤波器性能的影响。设计了多级级联CIC内插滤波器,利用"剪除"理论对每一级的输出位宽进行有效截取,在满足设计精度的前提下,不浪费硬件资源。采用多相滤波结构,将滤波器的工作时钟降低到单项滤波结构的1/4,降低运算模块设计难度,最高可实现1 GHz的工作频率。为满足不同的应用环境要求,设计了可编程控制模块,可实现2~63倍的不同插值。应用于某数字上变频电路中,基于0.18μm CMOS工艺流片,测试结果验证了所设计的滤波器功能可满足实际应用需求。

The characteristics of cascade integrator-comb filter(CIC filter)and the influence of main parameters on the performance of the filter are analyzed in principle.Multi-stage CIC interpolation filter is designed,and the output bit width of each stage is effectively intercepted by using the"cutting off"theory to meet the design accuracy,no hardware resources are wasted.The multi-phase filtering structure is adopted to reduce the working clock of the filter to one quarter of that of the single filtering structure,reduce the design difficulty of the operation module,and achieve the highest operating frequency of 1 GHz.In order to meet the requirements of different application environments,programmable control modules are designed,which can achieve 2-63 times different interpolation.The simulation and test results verify that the designed filter function is correct and can be applied to digital up-conversion circuit.Applied in a digital up-conversion circuit,based on0.18μm CMOS process tape out,the test results verify that the designed filter module can meet the practical application.