DTMF\0.wav ....\1.wav ....\2.wav ....\3.wav ....\4.wav ....\5.wav ....\6.wav ....\7.wav ....\8.wav ....\9.wav ....\A.wav ....\B.wav ....\C.wav ....\D.wav ....\dtmf1.wav ....\fourier.pdf ....\p.wav ....\paper_dtmf.pdf ....\pure1209.wav ....\pure697.wav ....\s.wav ....\基于DTMF用声音的频率打电话.doc DTMF