音频信号分析仪设计

基于离散傅里叶变换原理，以单片机和可编程逻辑器件FPGA构成的最小系统为控制核心，由前级信号调理模块、抗混叠滤波模块、AD637检波模块、A／D采样模块等模块构成。采用数字信号处理技术．在FPGA内部完成了2048点的浮点型FFT计算，能准确判断频率成分在20Hz～10kHz、幅值范围在0．1mV-10V的输入信号的功率谱及其总功率，频率分辨力最高可达10Hz，并能分析正弦信号的失真度。系统对待测量5s刷新一次并可实时显示。另外还增加了掉电存储回放显示及信号频谱显示的功能。

A Design for Auto Signal Analyzer with High-frequency Resolution

Based on DFT（Discrete Fourier Transform） principle, the system constituted by microcontroller and FPGA is used as for the control core. The composition modules are previous level signal conditioning modules, antialiasing filter module, AD637 detector module, and A/D sampling modules. Using digital signal processing technology, in the FPGA, the 2 048-point FFT floating-point calculation is completed, which can accurately determine the frequency components of the 20Hz-10kHz, and the power spectrum and the total power of the 0.1 mV- 10 V input signal, and the frequency resolution is up to 10 Hz. The sinusoidal signal distortion is analyzed also. The system do the measurement with 5 s refresh, display real time, and has the power-down memory playback display and signal spectrum display functions.