基于FPGA与单片机的音频频谱分析系统设计

Design of audio spectrum analyzer based on FPGA and MCU

详细介绍了一种基于FPGA与单片机的音频频谱分析系统的实现。整个系统由信号预处理电路、单片机最小系统和FPGA目标板模块3部分组成。预处理电路负责声音-电压信号的转换以及电压信号的放大;单片机最小系统完成音频信号的测频、采集与存储、LCD液晶屏的频谱显示以及相关的时序控制工作;FPGA部分对单片机ADC所采集的音频信号进行快速傅里叶变换(FFT),然后将变换后的结果返回并在液晶屏上显示。系统实现了对20Hz～20kHz音频信号的采集与频谱分析,该系统具有较好的实时性和准确性,频谱刷新时间小于0.5s,最大误差约为10%。

This paper introduces the design of audio spectrum analyzer based on FPGA and MCU. The whole system consists ot three parts, which are signal preproeessing circuit, MCU nlininmm system and FPGA target board. The signal preprocessing circuit is responsible for the convert of audio to voltage and the enlargement of vohage. MCU minimum system takes charge of measuring the frequency of audio signal, then selects a right sample frequency and store them, 3＂he FPGA part does tile FFT for the data which the AI）C of MCU has collected, then returns the FFr result to MCU and displays it on the LCD. This system succeeds in analyzing the audio between 20 Hz to 20 kHz. The system is real-time and has good accuracy, LCD refresh time is less than 0.5 s, and the maximum error is about 10 percent.