Multi-Channel MEMS Microphone PDM Decoding System Based on FPGA
Digital MEMS microphones are usually output in pulse density modulation(PDM)cod-ing,and it is generally necessary to convert PDM to pulse code modulation(PCM)signals before fur-ther processing.To solve such problems,an FPGA-based multi-channel PDM decoding system is de-signed and implemented.The system can realize multi-channel MEMS microphone data acquisition,de-coding,and local audio recording via Ethernet.The decoding scheme adopts a three-stage filter architec-ture consisting of a cascaded integral comb filter(CIC),a half-band filter,and a finite impulse response(FIR)filter to realize 32-fold downsampling;and is validated by simulation using MATLAB and Model-sim platforms.Based on the official IP core,a multi-channel resource multiplexing design method is pro-posed to realize 8-channel PDM decoding.Experiments show that the system has low resource utiliza-tion on FPGA,good demodulation performance,strong system expandability,and can be applied to larg-er scale microphone arrays.
pulse density modulationMEMS microphonesFPGAmulti-channelCIC filters
万方数据
维普
