关键词: 级联积分梳状滤波器, 内插, 可编程, 多级级联, 多相滤波

Abstract: 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 on 0.18 μm CMOS process tape out, the test results verify that the designed filter module can meet the practical application.

Key words: cascadeintegrator-combfilter, interpolation, programmable, multilevelcascade, polyphasefilter