一个离散傅立叶变换的实例程序。展示了利用Matlab内建fft函数进行频谱分析的过程。给出了幅度频谱和相位频谱。-A discrete Fourier transform demonstration program in Matlab: Fs sampling frequency fft built-in fft function fftshift built-in function to rearrange the output of fft by moving the zero