Echo cancellation in telephones with multiple microphones
First Claim
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1. A telephone that provides improved echo cancellation performance, comprising:
- a receiver that receives a far-end audio signal comprising a voice component of a far-end user;
a loudspeaker that converts the far-end audio signal into sound waves;
a first microphone that picks up the sound waves and outputs a first audio signal, the first audio signal including a first voice component associated with the voice of a near-end user and a second voice component associated with the voice of the far-end user;
a second microphone that outputs a second audio signal;
a voice activity detector (VAD) that processes the first audio signal, the second audio signal and the far-end audio signal to generate output relating to at least one of (i) time intervals in which the first voice component is present in the first audio signal and (ii) time intervals in which the second voice component is present in the first audio signal; and
an echo canceller that cancels the second voice component included in the first audio signal based on the output from the VAD, thereby producing a third audio signal.
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Abstract
The present invention is directed to a telephone equipped with multiple microphones that provides improved performance during operation of the telephone in a speaker-phone mode. For example, the multiple microphones can be used to improve voice activity detection, which in turn, can improve echo cancellation. In addition, the multiple microphones can be configured as an adaptive microphone array and used to reduce the effects of (i) room reverberation, when a near-end user is speaking, and/or (ii) acoustic echo, when a far-end user is speaking.
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Citations
26 Claims
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1. A telephone that provides improved echo cancellation performance, comprising:
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a receiver that receives a far-end audio signal comprising a voice component of a far-end user;
a loudspeaker that converts the far-end audio signal into sound waves;
a first microphone that picks up the sound waves and outputs a first audio signal, the first audio signal including a first voice component associated with the voice of a near-end user and a second voice component associated with the voice of the far-end user;
a second microphone that outputs a second audio signal;
a voice activity detector (VAD) that processes the first audio signal, the second audio signal and the far-end audio signal to generate output relating to at least one of (i) time intervals in which the first voice component is present in the first audio signal and (ii) time intervals in which the second voice component is present in the first audio signal; and
an echo canceller that cancels the second voice component included in the first audio signal based on the output from the VAD, thereby producing a third audio signal. - View Dependent Claims (2, 3, 4, 5)
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6. A telephone that provides improved performance, comprising:
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a microphone array, each microphone in the array configured to receive sound waves and to generate an audio signal corresponding thereto; and
a digital signal processor (DSP) that receives the audio signals from the microphone array and is configured to detect a direction of arrival (DOA) of at least one of (i) sound waves corresponding to a reverberation of a voice of a near-end user and (ii) sound waves corresponding to a voice signal of a far-end user, wherein the DSP adaptively combines the audio signals from the microphone array based on the DOA to produce a first audio output signal. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
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14. A method for processing audio signals in a telephone having at least two microphones, comprising:
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receiving a far-end audio signal comprising a voice component of a far-end user;
converting the far-end audio signal into sound waves;
picking up the sound waves and outputting a first audio signal from the first microphone, the first audio signal including a first voice component associated with the voice of a near-end user and a second voice component associated with the voice of the far-end user;
outputting a second audio signal from a second microphone;
processing the first audio signal, the second audio signal and the far-end audio signal in a voice activity detector (VAD) to generate output relating to at least one of (i) time intervals in which the first voice component is present in the first audio signal and (ii) time intervals in which the second voice component is present in the first audio signal; and
canceling the second voice component included in the first audio signal based on the output of the VAD, thereby producing a third audio signal. - View Dependent Claims (15, 16, 17, 18)
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19. A method for processing audio signals in a telephone having a microphone array, comprising:
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(a) outputting an audio signal from each microphone in the microphone array based on sound waves incident thereon;
(b) detecting a direction of arrival (DOA) of at least one of (i) sound waves corresponding to a reverberation of a near-end user'"'"'s voice and (ii) sound waves corresponding to a far-end user'"'"'s voice; and
(c) adaptively combining the audio signals based on the DOA to produce a first audio output signal. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26)
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Specification