说明：  1.加深对离散时间信号的DTFT基本概念的理解。 2.熟悉DFT变换原理及其基本性质。加深对DTFT和DFT相互关系的理解 3.熟悉FFT算法原理和FFT子程序的应用 4.掌握用MATLAB计算离散时间信号的DTFT和DFT的方法，FFT函数的用法。
(1、Deepen their understanding of discrete-time signal DTFT understanding of basic concepts. 2、DFT-familiar with the principle and its basic properties. DTFT and DFT deepen the understanding of the relationship between)