Voice activity detector for half-duplex audio communication syst

Details Voice activity detector for half-duplex audio communication syst Voice activity detector for half-duplex audio communication syst

1995-08-28

1997-01-28

Zele, Krista M.

Telephonic communications

Supervisory or control line signaling

Using line or loop condition detection

379351, 381 56, 395 242, H04M 910, H04M 908, G10L 300, G10L 918

Patent

active

055984665

ABSTRACT:
A method of detecting voice in an audio signal comprises the steps of determining an average peak value representing an envelope of the audio signal, determining a running instance of audio signal standard deviation, which corresponds to one of a number of overlapping time intervals, and updating a power density function (PDF) by adding instances of noise to the PDF if the average peak of the audio signal exceeds the current level of the audio signal by a certain amount and if the current standard deviation value falls below a threshold for a predetermined time interval. A noise floor is located based on the mean value of the PDF, and, if the audio signal sustains a power level exceeding the noise floor, voice activity is determined to be present in the audio signal. The PDF is updated by a low confidence factor if all of the standard deviation values calculated during a certain period of time are below the threshold value and by a high confidence factor if all standard deviation values within a certain longer period of time period are below the threshold value.

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