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Method and apparatus for overcoming periodic disturbances in digital subscriber loops

  • US 6,330,275 B1
  • Filed: 06/19/1998
  • Issued: 12/11/2001
  • Est. Priority Date: 06/23/1997
  • Status: Expired due to Term
First Claim
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1. An apparatus for canceling periodic impulse noise coupled into a twisted wire pair of a transmission system, the periodic impulse noise being generated by a source external to the transmission system, the apparatus comprising:

  • a receiver coupled to first ends of the twisted wire pair, the receiver receiving an electrical signal being propagated along the twisted wire pair;

    a detector disposed to detect a periodic impulse signal coupled into the twisted wire pair, the detector generating a signal relating to the detected periodic impulse signal;

    a sampling/scaling device coupled to the detector, the sampling/scaling device receiving the signal generated by the detector and sampling and scaling the signal to produce a representation of the signal generated by the detector, the sampling/scaling device utilizing the representation to generate a periodic impulse cancellation signal, the sampling/scaling device converting the periodic impulse cancellation signal into an analog periodic impulse cancellation signal;

    an adder device coupled to the twisted wire pair and to the sampling/scaling device, the adder device receiving the analog periodic impulse cancellation signal and adding the analog periodic impulse cancellation signal to the twisted wire pair, wherein the periodic impulse signal coupled into the twisted wire pair is reduced by the analog periodic impulse cancellation signal, and the electrical signal received by the receiver includes the reduced periodic impulse signal.

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