说明：  关于傅立叶变换，无论是书本还是在网上可以很容易找到关于傅立叶变换的描述，但是大都是些故弄玄虚的文章，太过抽象，尽是一些让人看了就望而生畏的公式的罗列，让人很难能够从感性上得到理解。这是一份很好的傅里叶算法的入门资料
(Fourier transformation, whether in books or on the Internet can be very easy to find a description of the Fourier transform, but are some articles trick, too abstract, do some people looked at a list of the formulas on the daunting, people very difficult can be understood from the emotional. This is a very good Fourier algorithm introductory information)