Data processing: speech signal processing – linguistics – language – Speech signal processing – Recognition
Reexamination Certificate
2005-05-03
2005-05-03
Knepper, David D. (Department: 2654)
Data processing: speech signal processing, linguistics, language
Speech signal processing
Recognition
C704S233000
Reexamination Certificate
active
06889187
ABSTRACT:
A method and apparatus for detecting and transmitting voice signals in a packet voice network system. The method and apparatus make use of a voice activity detection (VAD) unit at a transmitter, for determining if an input signal contains active audio information or passive audio information, where the input signal includes a plurality of frames. For one or more frames of the input signal containing active audio information, the VAD computes a hangover time period. This computation includes determining whether the hangover time period has a fixed duration or a variable duration on the basis of characteristics of the active audio information contained in the one or more frames. When the VAD detects a frame containing passive audio information subsequent to the one or more frames containing active audio information, the input signal is suppressed after the expiry of the computed hangover time period from the detection of the passive audio information.
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Carleton University, Report on Voice Activity Detection for Packet Voice Transport; Dr. W.P. LeBlanc and Dr. S.A. Mahmoud, Dec. 15, 1997.
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ETSI EN 300 973 V7.0.1 (2000-01); Digital cellular telecommunications system (Phase 2+); Half rate speech; Voice Activity Detector (VAD) for half rate speech traffic channels (GSM 06.42 version 7.0.1 Release 1998).
Crane John D.
Knepper David D.
Nortel Networks Limited
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