双音多频 DTMF（Dual Tone Multi Frequency），由高频群和低频群组成，高低频群各包含 4 个频率。一个高频信号和一个低频信号叠加组成一个组合信号，代表一个数字。本代码对一段输入的语音信号文件进行分析，得到对应的数字

-DTMF (Dual Tone Multi Frequency), by the high frequency group and low frequency group, high and low frequency group each contain 4 frequency. A high frequency signal and a low frequency signal are superimposed to form a combined signal, which represents a number. The code for a number of input speech signal analysis to obtain the corresponding figures