Application of MUSIC algorithm to DTMF detection

DTMF is a signalling system used in telephony. When DTMF is sent in-band and carries sensitive information, this data often must be removed. Inaccurate removal procedure results in fractions of DTMF remaining. In this paper MUSIC is presented as a powerful method for removal of DTMF fractions. Compared to standard methods that utilize periodogram, e.g. Goertzel algorithm – MUSIC is shown to be quicker, more robust and accurate. For reliable DTMF detection in 8 kHz telephony, MUSIC needs only 8 samples (1 ms), Goertzel needs at least 110 samples (13.75 ms).