基于时域抽取的1024点FFT函数。适合用于演示算法计算过程，既教学。可以扩展成2次幂点数的FFT计算。开发环境MATLAB。-1024-point Decimation-in-time FFT function. Algorithm suitable for presentation process, both the teaching. Can be expanded into a power of two points of the FFT calculation. Development