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Timing recovery with variable bandwidth phase locked loop and non-linear control paths

  • US 7,154,979 B2
  • Filed: 03/11/2002
  • Issued: 12/26/2006
  • Est. Priority Date: 10/31/2001
  • Status: Expired due to Fees
First Claim
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1. A method of enhancing jitter tolerance in a communications network, comprising:

  • providing at least two non-linear paths, a first of said non-linear paths to adjust a phase of an input data in response to a data pattern of said input data, and a second of said non-linear paths to adjust said phase of said input data in response to an amplitude of data samples from said input data, and a phase locked loop to lock a phase of a clock to said phase of said input data;

    inputting said input data to said communications network;

    estimating a phase error based on said data samples from both a center of a data eye of said input data and from a phase sample from said input data half-a-baud later in time, said data samples and said phase sample being derived from said input data;

    correlating said phase error with a sign of recovered data to provide a correlated phase error, the sign being a positive or negative value;

    filtering said correlated phase error by a loop filter to generate an output;

    summing said output with output from said at least two non-linear paths to generate a summed output; and

    converting said summed output into clock phase information.

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