该段代码能实现找出隐藏或淹没在噪声时域信号中信号的频率成分。用FFT对试验数据进行谱分析，指出数据包含的频率成份。-One use FFT is to find hidden or submerged in the time domain signal noise frequency components of the signal. Test data with FFT spectrum analysis, pointed out that the data contained in freq