Post-Implementation Evaluation of CIC Filters for Digital Audio Applications on FPGA

This paper examines the implementation and resource utilization of Cascaded Integrator Comb (CIC) filters within FPGA-based Pulse Density Modulation (PDM) microphone applications. Three CIC filter designs were analyzed: one generated using MATLAB’s HDL Coder toolbox, one generated via AMD’s CIC Compiler IP, and one generated using an open-source CIC filter architecture. The study compares the efficiency of these three implementations in terms of slice LUTs and slice register usage. The maximum working frequency was also investigated. The results demonstrate that filters generated with the CIC Compiler require fewer FPGA resources, provide optimized multi-channel support, and have the option to utilize DSP48 slices for enhanced performance, while MATLAB-generated filters have higher working frequency and have great flexibility regarding the parameter, like the open-source CIC filter version.