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Digital subscriber line modem utilizing echo cancellation to reduce near-end cross-talk noise

  • US 6,263,077 B1
  • Filed: 02/23/1998
  • Issued: 07/17/2001
  • Est. Priority Date: 10/03/1997
  • Status: Expired due to Term
First Claim
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1. A communication system for use with a subscriber line, the communication system comprising:

  • a customer digital subscriber line modem, located at a customer site, coupled to the subscriber line, the customer digital subscriber line modem receiving downstream signals in a first frequency band from the subscriber line and transmitting upstream signals in a second frequency band to the subscriber line; and

    an office digital subscriber line modem coupled to the subscriber line, the office digital subscriber line transmitting the downstream signals to the subscriber line in the first frequency band and receiving the upstream signals from the subscriber line in the second frequency band, the office digital subscriber line modem including a transmitter for providing the downstream signals, an echo canceler, and an analyzer, the echo canceler being coupled to the transmitter and the subscriber line, the echo canceler providing a line signal representing the signals on the subscriber line that have the downstream signals canceled, the analyzer receiving the line signal and generating a feedback signal representing preemphasis for the downstream signals in accordance with the line signal, the transmitter adjusting the downstream signals in accordance with the feedback signal.

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