EP 0427713 A4 19920311 - MODEM WITH IMPROVED REMOTE ECHO LOCATION AND CANCELLATION
Title (en)
MODEM WITH IMPROVED REMOTE ECHO LOCATION AND CANCELLATION
Publication
Application
Priority
US 3213187 A 19870327
Abstract (en)
[origin: WO8807792A1] The field of the invention relates to echo cancellation by a modem using a communication link such as a two-wire telephone link. Prior art systems assume the most significant remote echo occurs at the remote end, consequenctly requiring the remote modem be active in order to locate a time interval for echos and providing inadequate determination of the time interval for intermediate echos. The invention identifies a remote echo returning to the modem corresponding to previously transmitted data, and includes a transmitter (20), a receiver (46), a store and compare element (36) which compares the received digital words to stored transmit data, and a delay element (32) which delays the transmit data input to a far end canceller (54) in accordance with the output of the store and compare element (36).
IPC 1-7
IPC 8 full level
H04B 3/23 (2006.01)
CPC (source: EP)
H04B 3/237 (2013.01)
Citation (search report)
- [A] PATENT ABSTRACTS OF JAPAN, vol. 11, no. 31 (E-475)[2478], 29th January 1987; & JP-A-61 199 338 (NEC) 03-09-1986
- [A] ELECTRONICS LETTERS, vol. 22, no. 4, 13th February 1986, pages 199-200, Stevenage, Herts, GB; A.D. FAGAN et al.: "In-band least-squares echo canceller"
- See references of WO 8807792A1
Designated contracting state (EPC)
DE FR GB SE
DOCDB simple family (publication)
WO 8807792 A1 19881006; AU 1549988 A 19881102; EP 0427713 A1 19910522; EP 0427713 A4 19920311
DOCDB simple family (application)
US 8800820 W 19880229; AU 1549988 A 19880229; EP 88903552 A 19880229