单音多频信号的产生和识别，采用FFT变换。应用于电话拨号。是学习数字信号处理的大作业。-Tone multi-frequency signal generation and recognition, the use of FFT transform. Applies to telephone dial-up. Digital Signal Processing is the study of large operations.

音频平移，从而实现单声道转换至双声道或多声道，音频空间效果实现。-Audio translation, in order to achieve conversion to two-channel mono or multi-channel audio to achieve spatial effects.