Data processing: speech signal processing – linguistics – language – Speech signal processing – Application
Patent
1997-07-07
1999-11-09
Kuntz, Curtis A.
Data processing: speech signal processing, linguistics, language
Speech signal processing
Application
381108, 381 943, G10L 500
Patent
active
059831839
ABSTRACT:
An automatic gain control (AGC) algorithm is provided to the digital signal processor instructions of an audio processing unit of a multimedia multipoint server. The AGC algorithm operates to bring the power level of the audio signal of every active channel to within a fixed range. The AGC algorithm allows the use of non-calibrated microphones, corrects for long distance signal attenuation, and provides improved audio level reference for audio switching and audio level video switching. The AGC algorithm is structured into two steps: calibration and gain control. The calibration includes defining a noise threshold. Gain control includes first calculating a dynamic speech detection level. Second, with reference to the speech detection level, determining whether an incoming audio signal is a speech-based audio signal. Finally, when the audio signal is determined to be of speech, calculating a smoothed power estimation of the speech signal, and appropriately updating the gain on each channel so that the power level of the speech signal is moved toward or confined within the fixed experimental range.
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Breton Yonik
Tabet Jad
Gallagher Thomas A.
General Data Comm Inc.
Gordon David P.
Jacobson David S.
Kuntz Curtis A.
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