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

  • US 20030169837A1
  • Filed: 03/11/2002
  • Published: 09/11/2003
  • Est. Priority Date: 10/31/2001
  • Status: Active Grant
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 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 local clock to said phase of said input data;

    inputting data to said communications network;

    estimating 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;

    correlating said phase error with a sign of recovered data;

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

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

    converting said summed output into clock phase information.

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