Telephonic communications – Substation or terminal circuitry – For loudspeaking terminal
Patent
1990-11-30
1993-02-16
Dwyer, James L.
Telephonic communications
Substation or terminal circuitry
For loudspeaking terminal
379389, 379390, 379406, 370 321, H04M 160
Patent
active
051877414
ABSTRACT:
An acoustic calibration circuit in a voice switched adaptive speakerphone accurately determines the type of acoustic environment of both large and small rooms having either harsh or favorable acoustics. The calibration circuit determines the acoustic environment of a room by emitting a tone burst through a loudspeaker associated with the speakerphone and generating an echo decay parameter that is indicative of the duration of echoes from the tone burst signal measured with a microphone also associated with the speakerphone. The echo decay parameter is generated from a composite representation of the acoustic response for those echoes having the largest returned amplitude level measued at each one of multiple predetermined time intervals by the calibration circuit. By examining the amplitude levels in the composite representation at selected ones of the multiple predetermined time intervals, the echo decay parameter or estimate for the additional time required for the echoes to dissipate to a desired level is generated. If after performing a first measurement of the room acoustics at a prescribed first time period, the calibration circuit determines that the room echoes have not dissipated to an acceptable level in this first time period for generating a satisfactory echo decay parameter representative of these echoes, the calibration circuit regenerates the tone burst into the room a second time and then measures the resulting level of the acoustic response over an extended time period. From the echo decay parameter and the composite representation, a time-domain acoustic response is generated. This time-domain acoustic response provides an estimate of both the maximum returned amplitude and expected duration of the echoes. This information is then used by the speakerphone in adapting its operating parameters. If the room acoustics are harsh, the speakerphone adapts by keeping its switching response comparable with that of a typical analog speakerphone. If acoustics are favorable, however, it speeds up the switching time, lowers both the break in thresholds and the total amount of inserted switched loss.
REFERENCES:
patent: 3725585 (1973-04-01), Moniak et al.
patent: 4525856 (1985-06-01), Admiral et al.
patent: 4571461 (1986-02-01), Uno et al.
patent: 4715063 (1987-12-01), Haddad et al.
patent: 4796287 (1989-01-01), Reesor et al.
patent: 4887288 (1989-12-01), Erving
patent: 4901346 (1990-02-01), Erving
patent: 4959857 (1990-09-01), Erving et al.
patent: 4979163 (1990-12-01), Erving et al.
Erving Richard H.
Miller Robert R.
AT&T Bell Laboratories
Dwyer James L.
Shehata M.
Williamson Samuel R.
LandOfFree
Enhanced acoustic calibration procedure for a voice switched spe does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Enhanced acoustic calibration procedure for a voice switched spe, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Enhanced acoustic calibration procedure for a voice switched spe will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2153619