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Adaptive method and apparatus for detecting a stutter dial tone signal

  • US 6,072,869 A
  • Filed: 12/22/1997
  • Issued: 06/06/2000
  • Est. Priority Date: 12/22/1997
  • Status: Expired due to Term
First Claim
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1. A method of detecting a stutter dial tone SDT signal, the method comprising the steps of:

  • a) receiving a received signal from a subscriber loop;

    b) generating a signal envelope of said received signal;

    c) generating a threshold parameter value from said signal envelope;

    c) counting the number of threshold parameter crossings undertaken by said signal envelope; and

    d) producing a signal indicating said SDT signal has been received when said number of threshold crossings exceeds a predefined value.

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