1
Daniel K Freeman, Ivan Boyd: Voice activity detection. British Telecommunications public company, Nixon & Vanderhye, January 4, 1994: US05276765 (85 worldwide citation)

Voice activity detector (VAD) for use in an LPC coder in a mobile radio system uses autocorrelation coefficient R.sub.0, R.sub.1 . . . of the input signal, weighted and combined, to provide a measure M which depends on the power within that part of the spectrum containing no noise, which is threshol ...


2
Huan Yu Su, Adil Benyassine, Jes Thyssen: Speech encoder using voice activity detection in coding noise. Conexant Systems, November 23, 2004: US06823303 (78 worldwide citation)

A multi-rate speech codec supports a plurality of encoding bit rate modes by adaptively selecting encoding bit rate modes to match communication channel restrictions. In higher bit rate encoding modes, an accurate representation of speech through CELP (code excited linear prediction) and other assoc ...


3
Antti Vahatalo, Juha Hakkinen, Erkki Paajanen: Method and device for voice activity detection and a communication device. Nokia Mobile Phones, Perman & Green, October 5, 1999: US05963901 (71 worldwide citation)

The invention concerns a voice activity detection device in which an input speech signal (x(n)) is divided in subsignals (S(s)) representing specific frequency bands and noise (N(s)) is estimated in the subsignals. On basis of the estimated noise in the subsignals, subdecision signals (SNR(s)) are g ...


4
Jes Thyssen, Huan yu Su, Yang Gao, Adil Benyassine: Speech codec employing noise classification for noise compensation. Conexant Systems, May 29, 2001: US06240386 (71 worldwide citation)

A multi-rate speech codec supports a plurality of encoding bit rate modes by adaptively selecting encoding bit rate modes to match communication channel restrictions. In higher bit rate encoding modes, an accurate representation of speech through CELP (code excited linear prediction) and other assoc ...


5
Fu Hua Liu, Michael A Picheny: Model-based voice activity detection system and method using a log-likelihood ratio and pitch. International Business Machines Corporation, F Chau & Associates, September 2, 2003: US06615170 (68 worldwide citation)

A system and method for voice activity detection, in accordance with the invention includes the steps of inputting data including frames of speech and noise, and deciding if the frames of the input data include speech or noise by employing a log-likelihood ratio test statistic and pitch. The frames ...


6
David Lind Weigand: Telephone receiver circuit with dynamic sidetone signal generator controlled by voice activity detection. National Semiconductor Corporation, Vedder Price Kaufman & Kammholz P C, February 1, 2005: US06850617 (67 worldwide citation)

A telephone receiver circuit with sidetone signal generation controlled by voice activity detection in accordance with the present invention uses the voice activity detector (VAD) to detect the presence of voice activity within the microphone signal and dynamically adjust the sidetone signal generat ...


7
Andre DesBlache, Claude Galand, Robert Vermot Gauchy: Voice activity detection process and means for implementing said process. International Business Machines, John B Frisone, June 9, 1987: US04672669 (67 worldwide citation)

Speech signal presence is detected in a VAD (Voice Activity Detector) in two steps: (1) Signal energy above a threshold decides presence, below threshold decides ambiguity; (2) ambiguity is resolved by testing the rate of change of spectral parameters.


8
Daniel J Marchok, Richard C Younce, Charles W K Gritton: Consolidated voice activity detection and noise estimation. Tellabs Operations, Banner & Witcoff, February 25, 2003: US06526140 (62 worldwide citation)

Methods and apparatus for processing at least one voice signal in which a centralized voice processing unit controls operation of a plurality of voice processing block. In a first embodiment, the centralized voice processing unit comprises a centralized voice activity detector that provides at least ...


9
John T Chapman, Guenter Roeck, Sunil Khaunte: Method and apparatus for mapping voice activity detection to a scheduled access media. Cisco Technology, Marger Johnson & McCollom PC, September 16, 2003: US06621812 (61 worldwide citation)

Unsolicited grants are allocated a selected time interval for scheduling transmission of audio packets at a network endpoint. A network processing node switches from outputting unsolicited grants to polling for packet transmission requests when Voice Activity Detection (VAD) at the transmitting endp ...


10
Päivi Valve: Method and system for tracking human speakers. Nokia Mobile Phones, Ware Fressola Van Der Sluys & Adolphson, September 10, 2002: US06449593 (48 worldwide citation)

A method and system for tracking human speakers using a plurality of acoustic sensors arranged in an array to detect the voice of the speakers within an angular range in order to determine a most favorable direction for detecting the voice in a detection period. A beamformer is used to form a plural ...