Abstract: The Dual Tone Multi-Frequency DTMF is the dialing signal in the new generation of telephone.It is a worthy engineering application to gather DTMF detection to the Digital Signal Processor system.This article puts forward a scheme to implement Goertzel algorithms and DTMF detection in the use of a Texas Instruments C6711 floating point DSP.DTMF detection is performed using 20 parallel Goertzel filters,which makes the detecting accurate,quick and simple.It is proved that precision of detected system has been improved greatly by resonance sound detection.

Key words: goertzel filter, DTMF(the dual tone multi-frequency), digital signal processor(DSP), bellcore specification