Apparatus and method for identifying speech and call-progression

Details Apparatus and method for identifying speech and call-progression Apparatus and method for identifying speech and call-progression

1992-05-26

1994-06-07

Dwyer, James L.

Telephonic communications

Supervisory or control line signaling

Signalling integrity protection

379386, 379 84, 379 86, 381 41, 381 46, 3701103, H04M 100

Patent

active

053197038

ABSTRACT:
A method for real-time recognition of speech and call-progression tone energy includes the steps of digitizing an analog signal present on a signal line, correlating N neighboring portions of the digitized signal, performing FFT analysis on the digitized signal, identifying the three largest frequency-domain maxima, determining whether the two largest maxima are above a threshold frequency, and determining whether the ratio of the largest to the third largest maxima exceeds a predetermined value. According to the present invention, the steps of the method may be performed in real time using fixed-point hardware by approximating the correlation and FFT functions.

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