数字信号处理中的离散傅里叶变换用快速傅里叶变换算法实现（为按时间抽取FFT算法实现的程序；考虑到补零情况，进行信号频谱分析过程中可能出现的问题，例如混淆、泄漏、栅栏效应等）-Program of digital signal processing in the discrete Fourier transform using a fast Fourier transform algorithm (as achieved by the decimation-in-time FFT algorith