Acoustic echo control
AssigneeMagor Communications Corporation
InventorsKathryn ADENEY, Dean SWAN
Life of this patent
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Abstract
Processing requirements for echo cancellation in voice communications are significant and are even more so as the bandwidth of the communication increases. Whilst voice communication occupies a relatively narrow band of frequencies the processing requirements and so forth for wideband communication render echo cancellation difficult to achieve in a cost effective manner. The invention provides for provides echo cancellation within wideband communications by dividing the communications into sub-bands and applying echo cancellation to some sub-bands whilst processing other sub-bands according to the status of the communications. Additional sub-bands are transmitted at either full-duplex or half-duplex.
Claims27
A method comprising:
- receiving at a first port a first signal representative of a first audio signal;
- receiving a second signal representative of a second audio signal for transmission;
- performing echo cancellation of the second signal within at least a first band of audio frequencies;
- detecting within at least one of the first signal and the second signal speech activity within at least a predetermined band;
- when speech activity is detected other than providing portions of the first audio signal within a second other band, at least some of the second other band outside the first band, to a loudspeaker while providing portions of the first audio signal within the first band to the loudspeaker;
- when acoustic activity is other than detected providing portions of the first audio signal within the second other sub-band to a loudspeaker while providing portions of the first audio signal within the first band to the loudspeaker.
A method comprising:
- filtering a first signal representative of a first audio signal from a first location into a plurality of sub-band signals, each sub-band signal representing the portion of the first signal within a predetermined range of acoustic frequencies;
- filtering a second signal representative of a second audio signal from a second location into a plurality of sub-band signals, each sub-band signal representing the portion of the second signal within a predetermined range of acoustic frequencies;
- transmitting a predetermined portion of the plurality of sub-band signals of each of the first audio signal and the second audio signal to the other location in a half-duplex arrangement;
- and
- transmitting the remainder of the plurality of sub-bands of at least one of the first audio signal and the second audio signal to the other location in a full-duplex arrangement.
A method comprising:
- receiving a first signal representative of a first audio signal;
- receiving a second signal representative of a second audio signal;
- performing echo cancellation of the second signal within a first band of audio frequencies;
- detecting within the first signal acoustic activity within the first band of audio frequencies;
- when acoustic activity is detected other than providing portions of the first audio signal within a second other band, at least some of the second other band outside the first band, to a loudspeaker while providing portions of the first audio signal within the first band to the loudspeaker;
- and,
- when acoustic activity is other than detected providing portions of the first audio signal within the second other band to a loudspeaker while providing portions of the first audio signal within the first band to the loudspeaker.
A method of transmitting acoustic information comprising:
- transmitting acoustic information within a first band and third band of frequencies in full duplex;
- and
- transmitting acoustic information within a second and fourth other band of frequencies and having half-duplex echo cancellation applied thereto.
A method of transmitting acoustic information comprising:
- transmitting acoustic information within a first band of frequencies in full duplex;
- detecting voice activity within the first band;
- and
- controlling switched loss within at least another band of frequencies of the acoustic information in dependence upon the detected voice activity.
A system comprising:
- a transceiver for transmitting acoustic information within a first band of frequencies in full duplex;
- a detector for detecting voice activity within the first band;
- and
- a switched loss controller for controlling switched loss within at least another band of frequencies of the acoustic information in dependence upon the detected voice activity.
Dependencies are inferred from the claim text.