直接法又称周期图法，它是把随机序列x(n)的N个观测数据视为一能量有限的序列，直接计算x(n)的离散傅立叶变换，得X(k)，然后再取其幅值的平方，并除以N，作为序列x(n)真实功率谱的估计。 -The direct method is also called cycle diagram method, it is the random sequence x (n) n observation data as a energy limited sequence, direct calculatio

（1）熟悉并掌握傅立叶变换 （2）了解傅立叶变换在图像处理中的应用 （3）通过实验了解二维频谱的分布特点 （4）用MATLAB实现傅立叶变换仿真 -(1) be familiar with and master the Fourier transform (2) understand the Fourier transform in image processing applications (3) experiments to understand the characteri

matlab平台基于傅立叶变换的信号频谱分析深度理解和仿真，一看就能明白！-Based on the signal spectrum analysis matlab platform Fourier transform depth understanding and simulation, a look can understand!