DTMF detector system and method which performs frequency domain

Details DTMF detector system and method which performs frequency domain DTMF detector system and method which performs frequency domain

1996-05-24

1998-09-15

Zele, Krista

Telephonic communications

Supervisory or control line signaling

Signal receiver

379282, 379283, H04M 300

Patent

active

058091335

ABSTRACT:
An improved dual tone multifrequency (DTMF) or multitone signal detector which more efficiently detects DTMF signals. For each received frame, the present invention initially performs only a portion of the Goertzel DFT algorithm for each of the possible tone frequencies and then analyzes the interim accumulated energies. The DTMF detector then selects one or more frequencies from each of the tone groups which have the largest energy values, and the detector only completes calculation of the Goertzel DFT algorithm on those selected one or more frequencies. In other words, the DTMF detector discontinues calculation of the Goertzel DFT algorithm on one or more frequencies which have low accumulated interim energies. This reduces the computational requirements and provides improved performance.

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