Decoding Technology of Dual-tone multi-frequency Signal

摘要

Dual-tone multi-frequency (DTMF) signal is common signal throughout the telephone network. It has a strong anti-jamming ability and fast transmission speed. This paper describes the basic theory of generation and detection of DTMF signal. Simulations are performed to compare the performances of DTMF decoding algorithms based on the FFT and the Goertzel. The frequency spectrum of the signal is analyzed directly by software-decoding system of DTMF signal. Results show that the two algorithms can compute the DTMF signal’s frequency, but the Goertzel algorithm is faster and more efficient than the FFT algorithm.