Telephonic communications – Subscriber line or transmission line interface – Network interface device
Patent
1995-01-26
1998-04-28
Hong, Harry S.
Telephonic communications
Subscriber line or transmission line interface
Network interface device
379406, 379411, 370 321, H04M 900
Patent
active
057455643
ABSTRACT:
In an echo canceller, an estimated echo signal is produced by an adaptive filter from a receive path signal and is subtracted from an incoming transmit path signal to produce an outgoing transmit path signal. Averages of signal levels on the receive path and the incoming and outgoing transmit paths are produced by exponential averaging. Adaptation of the adaptive filter is inhibited after initial convergence. Adaptation is enabled again in response to an echo attenuation parameter being less than a first threshold value and a variation of an echo attenuation parameter being less than a second threshold value, this situation representing a detected echo path change. The detection of an echo path change is inhibited in the presence of a near end signal. The echo attenuation parameters can be either or both of the ERLE (echo return loss enhancement) due to the subtraction of the estimated echo signal or the combined attenuation of the ERLE plus the ERL (echo return loss) of the hybrid circuit, these parameters being determined from averaged signal levels on the signal paths.
REFERENCES:
patent: 4360712 (1982-11-01), Horna
patent: 5153875 (1992-10-01), Takatori
patent: 5237562 (1993-08-01), Fujii et al.
patent: 5278900 (1994-01-01), Van Gerwen et al.
patent: 5283784 (1994-02-01), Genter
patent: 5307405 (1994-04-01), Sih
patent: 5577097 (1996-11-01), Meek
Haley R. John
Hong Harry S.
Northern Telecom Limited
Saint-Surin Jacques M.
LandOfFree
Echo cancelling arrangement does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Echo cancelling arrangement, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Echo cancelling arrangement will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1540558