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Methods and apparatus for noise conditioning in digital speech compression systems using linear predictive coding

  • US 5,642,464 A
  • Filed: 05/03/1995
  • Issued: 06/24/1997
  • Est. Priority Date: 05/03/1995
  • Status: Expired due to Term
First Claim
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1. A method for processing a speech signal comprising a plurality of successive signal intervals, each signal interval comprising a plurality of successive signal samples, the method comprising:

  • classifying each signal interval containing no speech sounds as a noise interval;

    classifying each signal interval containing speech sounds as a speech interval;

    calculating long window LPC coefficients for each noise interval based on the samples of that noise interval and a plurality of preceding signal intervals;

    calculating excitation parameters for each noise interval based on the samples of that noise interval and the long window LPC coefficients calculated for that noise interval;

    calculating short window LFC coefficients for each speech interval based only on the samples of that speech interval;

    calculating excitation parameters for each speech interval based on the samples of that speech interval and the short window LPC coefficients calculated for that speech interval; and

    combining the LPC coefficients and the excitation parameters calculated for each signal interval to encode that signal interval.

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