基-2 FFT在音频分析及输出系统中的应用

主要介绍了一种将FFT算法移植到单片机上运行，通过对数字音频信号进行分析处理，以实现音乐频谱实时显示和声音输出的系统。系统硬件部分主要由声音输入、单片机模数转换、由LED组成的点阵单元以及声音信号放大输出等电路组成。利用高性能STC12C5A60S2单片机内建的模数转换功能，先将输入的音频信号采样、量化转换为数字信号，再通过软件编程进行FFT运算。输出处理结果点亮LED点阵，完成频谱显示。LED的明暗由音乐的频率变化决定。通过LM386运放芯片及外围电路将输入的音频信号进行放大后，由喇叭或者外接音箱输出。该设计不但具有较高的实用价值和观赏性，而且硬件电路结构简洁，开发、制作成本低。

Application of base 2 FFT in audio analysis and output system

This paper mainly introduces a system which transplanted FFT algorithm into MCU to analyze and process the digital audio signal so as to make real time display and sound output of music spectrum come true. The hardware part of the system consists of audio input, single chip analog digital conversion, dot matrix unit composed of LED and sound signal amplification output circuit. Using high performance single chip STC12C5A60S2 comes with A/D conversion function, the first audio signal is converted to digital signals, and then write the program for FFT operation. Output processing results lighting LED matrix and complete spectrum display. The brightness of the LED is determined by the frequency of the music. Amplifying the input audio signal through the LM386 op amp chip and the external circuit, then output it by the speaker or an external speaker. The design not only has a high practical value and ornamental, and hardware circuit structure is simple. Development and production cost low.