为了解决离散傅里叶变换（DFT）计算量太大的问题，1965 年，Cooley-Tukey发表了他们的解决方法，将DFT的运算量减 少了几个数量级。我们称之为“快速傅里叶变换（FFT）”方法。 根据对序列分解与选取方法的不同而产生了FFT的多种算法， 本文将讨论按时间抽取（DIT）的基-2 FFT算法和按频率抽取（DIF） 的基-2 FFT算法。并给出了一个基2的N点FFT完整C语言程 序，在VC6.0中运行该程序，证实了快速傅里叶变换的可行性。

In order to solve the problem that the amount of calculating the discrete Fourier transform (DFT) is too heavy, in 1965, Cooley -Tukey published their solution, which `reduces the amount of calculating the DFT by some order of magnitude. Their solution is called as the fast Fourier transform (FFT). According to the difference of the sequence’s analysis and selection, there are many algorithms about FFT. In this paper, we will talk about Decimation-in-time (DIT) radix-2 FFT algorithm and Decimation in frequency (DIF) -2 FFT algorithm. And a complete code of the C Programming Language on radix-2 of N is given, when we run this program on the VC6.0, the result confirms the feasibility of the fast Fourier transform.