加深对离散信号的DTFT和DFT的及其相互关系的理解。；在理论基础上，加深对快速傅立叶变换的理解，熟悉FFT算法及其程序的编写；熟悉应用FFT对典型信号进行频谱分析的方法。-To deepen DTFT the discrete signal and DFT and its understanding of the relationship.　 On the basis of theory, deepen the understanding of fast Fourier transform, familiar with the writing of the FFT algorithm and its application　Be familiar with the application of FFT spectrum analysis was carried out on the typical signal method.