Echo canceller using initial training

摘要

A far-end modem (300) transmits a "pilot tone" during the time that a near-end modem (100) is training its echo canceller (650). Correspondingly, the near-end modem (100) is modified to notch or filter out this pilot tone from the received signal. The filtered received signal is then used by the near-end modem (100) to train its echo canceller (650). <IMAGE>