这是一个利用DSPIC33FJ64MC802芯片进行音频AD采样以及FFT变换（得到功率谱）并将得到的数据进行串口发送的程序。该程序用于一个声音功率谱分析的设计中。　　使用时需要配合外围的放大，滤波，加法器，以及电源等其他电路。并结合自编的上位机软件进行显示。

　　在Microchip给出的FFT函数中，256点FFT变换存在问题，无法得到正常数据。这是由于旋转因子表的错误造成的。本程序已经对其作出了修正。同时在功率谱计算的函数中，也作出了一些优化，在测量较小的幅值时，结果会更加理想。

　　本程序在音频分析与传输中，完全做到了实时分析。结合理想的上位机软件，可以进行实时系统的构建。这实在是相当难得的。但是，由于实时性的保证以及串口速率的限制，本系统频率分析的上限只能在5K左右（程序中采用了4K）。如果将通信接口改为SPI或其他高速接口，可以显著提高系统频率分析的上限。-This is a use of DSPIC33FJ64MC802 chip audio AD sampling and FFT transform (power spectrum) and will receive procedures for serial port to send data.The program is used for the design of a sound power spectrum analysis.When using need to cooperate with the periphery of the amplifier, filter, adder, and power, and other circuit.Combined with the feature of PC software for display.

FFT function in Microchip, the 256- point FFT transform problems, cannot get normal data.This is due to the fault of rotating factor table.This program has made a correction on it.In power spectrum calculation function at the same time, also made some optimization, when measuring small amplitude, the result will be more ideal.

This procedure in audio analysis and transmission, completely achieved real-time analysis.In combination with the PC software of ideal, can build the real-time system.This is really quite rare.But, as a result of the limitation of the guaranteed real-time and rate of serial port, the s