应用傅里叶变换DFT，分析各种离散信号x(k)的频谱。离散周期信号可以展开成傅里叶级数，所以离散周期信号的频谱 是一个周期的周期性离散频谱，各谱线之间的间隔为 ，而且存在着谐波的关系。 -DFT application of the Fourier transform, analyze discrete signal x (k) of the spectrum. Discrete signal cycle can begin as Fourier series, the discrete signal spectrum is a cyclical cycle of discrete spectrum, the line between the interval, but there is a harmonic relationship.