Telephone having four VAD circuits
AssigneeAcoustic Technologies, Inc.
InventorsSteven M. Domer, Kellie Michele Vanda
Life of this patent
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Abstract
Voice activity is detected by comparing a signal with two thresholds and producing data representing the energy of the signal. The data, in binary form, is compared with thresholds to determine voice activity. In accordance with another aspect of the invention, the thresholds are adjusted based upon statistical information. In accordance with another aspect of the invention, the data can be weighted to provide an indication of the quasi-RMS energy of an input signal. In accordance with another aspect of the invention, voice activity detectors, individually weighted, are provided at each input and each output of a telephone for reliably controlling echo cancelling circuitry within the telephone.
Claims11
In a telephone having a voice activity detector, the improvement comprising:
- a first voice activity detector having an input coupled to a microphone input and an output;
- a second voice activity detector having an input coupled to a line input and an output;
- a decode circuit coupled to the output of the first voice activity detector and to the output of the second voice activity detector and causing the telephone to enter a transmit state when the first voice activity detector indicates the presence of a voice signal and the second voice activity detector indicates the absence of a voice signal.
In a telephone having a line input, a line output, a microphone input, and a speaker output, the improvement comprising:
- a first voice activity detector coupled to said microphone input;
- a second voice activity detector coupled to said line output;
- a third voice activity detector coupled to said line input;
- and
- a fourth voice activity detector coupled to said speaker output.
7 The telephone as set forth in claim 6 and further including a first bank of band pass filters coupled between said first voice activity detector and said second activity detector, whereby said second voice activity detector detects residual acoustic echo.
The telephone as set forth in claim 7 and further including a second bank of band pass filters coupled between said third voice activity detector and said fourth activity detector, whereby said fourth voice activity detector detects residual line echo.
Dependencies are inferred from the claim text.