| 摘要 |
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). |
