Design of Audio Signal Analyzer Based on MCU and FPGA

This audio signal analyzer is based on a microcontroller (MCU) and a field programmable gate array (FPGA). It consists of a controllable gain amplifier circuit, an active filter circuit, A / D conversion and D / A feedback circuits, and a main control circuit and liquid crystal display module. Through AD conversion, the audio signal is sampled, the continuous signal is discretized, and then the FFT fast Fourier transform operation is performed to analyze and process each frequency component and power of the audio signal in the time and frequency domain. By controlling the gain of the amplifier to expand the dynamic range of the input signal and improve the sensitivity, it can also complete the corresponding human-computer interaction control based on the PS2 keyboard input, while using the high-resolution LCD to display the signal spectrum. The audio signal frequency range that this system can accurately measure is 20Hz-10KHz, its amplitude range is 5mVpp-5Vpp, and the resolution is divided into 20Hz and 100Hz. The measured power accuracy is as high as 1%, and the period of the periodic signal can be accurately measured, which is the ideal solution for audio signal analyzers.