快速傅氏变换（FFT），是离散傅氏变换的快速算法，它是根据离散傅氏变换的奇、偶、虚、实等特性，对离散傅立叶变换的算法进行改进获得的。它对傅氏变换的理论并没有新的发现，但是对于在计算机系统或者说数字系统中应用离散傅立叶变换，可以说是进了一大步。(Fast Fourier transform (FFT) is a fast algorithm for discrete Fourier transform. It is based on the characteristics of discrete Fourier transform, such as odd, even, virtual and real, and improves the algorithm of discrete Fu Liye transform. It has not found any new discoveries in the theory of Fourier transformation, but it is a great step to apply discrete Fu Liye transform in computer system or digital system.)