Telephonic communications – Supervisory or control line signaling – Using line or loop condition detection
Patent
1995-09-29
1998-06-09
Zele, Krista
Telephonic communications
Supervisory or control line signaling
Using line or loop condition detection
379390, 379409, 379410, 379411, 370286, 370291, H04M 100
Patent
active
057647534
ABSTRACT:
A double-talk detector for an echo canceller includes power estimators (60) and (62) which are utilized to measure the ERLE value in a calculator (64). This ERLE is stored in a register (70) when it is the largest value generated. This register (70) is updated whenever a new and better ERLE occurs. A fraction of the value in register (70) is utilized as an input to a comparator (88), and then compared to the current ERIE value. If the current ERLE differs from the SERLE in register (70) an inhibit signal is generated for blocking the updates of an adaptive filter (40). The value stored in the register (70) is periodically decremented to reduce the value thereof. This decrement operation is performed in response to detection of an utterance from the far-end. A half-Duplex operation is provided with two attentuators (352) and (354) to provide a switching operation and allow only one side access to the communication path. Speech, or the occurrence of an utterance is monitored at each end by comparing the raw input power at each end to a scaled up background noise power for that end. Different scaling factors for speech detection, or utterance detection, are provided, there being a high scaling factor and a low scaling factor. The side with the initially detected utterance will have access to the system and have the lowest scaling factor associated therewith, the other having the highest scaling factor associated therewith.
REFERENCES:
patent: 3832493 (1974-08-01), Clark
patent: 4029912 (1977-06-01), Geigel et al.
patent: 4131767 (1978-12-01), Weinstein
patent: 4213014 (1980-07-01), Luder
patent: 4469916 (1984-09-01), De Bergh et al.
patent: 4629829 (1986-12-01), Puhl et al.
patent: 4645883 (1987-02-01), Horna et al.
patent: 4813073 (1989-03-01), Ling
patent: 4864608 (1989-09-01), Miyamoto et al.
patent: 4879745 (1989-11-01), Arbel
patent: 4894820 (1990-01-01), Miyamoto et al.
patent: 4918727 (1990-04-01), Rohrs et al.
patent: 5014263 (1991-05-01), Vairavan et al.
patent: 5075687 (1991-12-01), Chen et al.
patent: 5099472 (1992-03-01), Townsend et al.
patent: 5132963 (1992-07-01), Ungerboeck
patent: 5170430 (1992-12-01), Schuh
patent: 5193112 (1993-03-01), Sano
patent: 5263019 (1993-11-01), Chu
patent: 5278900 (1994-01-01), Van Gerwen et al.
patent: 5327495 (1994-07-01), Shenoi et al.
patent: 5343521 (1994-08-01), Jullien et al.
patent: 5357567 (1994-10-01), Barron et al.
patent: 5365583 (1994-11-01), Huang et al.
patent: 5390250 (1995-02-01), Janse et al.
patent: 5418848 (1995-05-01), Armbruster
patent: 5434916 (1995-07-01), Hasegawa
patent: 5471528 (1995-11-01), Reesor
patent: 5473686 (1995-12-01), Virdee
K. Ochiai, et al., "Echo Canceller with Two Echo Path Models," IEEE Transactions on Communication, COM-25, No. 6, pp. 589-595, Jun. 1977.
D. L. Duttweiler, "A Twelve-Channel Digital Echo Canceller," IEEE Transactions on Communication, COM-26, No. 5, pp. 647-653, May 1978.
R. Harris, et al., "A Variable Step (VS) Adaptive Filter Algorithm," IEEE Transactions on Acoustics, Speech and Signal Processing, vol. ASSP-34, No. 2, pp. 309-316, Apr. 1986.
Joseph B. Evans, "Analysis of a Low Complexity Variable Step Size Adaptive Algorithm," IEEE, pp. III-484-487, 1993.
Dennis Morgan, "Considerations in the Design of a Speakerphone," Motorola Inc. Analog Integrated Circuits Division, Analog & Mixed Signal Design Conference 1995, pp. 41-1-41-6.
Hemkumar Nariankadu Datatreya
McCaslin Shawn Robert
Redheendran Bheeshmar
Crystal Semiconductor Corp.
Howison Gregory M.
Hsieh Shih-Wen
Violette J. P.
Zele Krista
LandOfFree
Half-duplex controller does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Half-duplex controller, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Half-duplex controller will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2210712