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Audio pre-processing methods and apparatus

  • US 4,856,068 A
  • Filed: 04/02/1987
  • Issued: 08/08/1989
  • Est. Priority Date: 03/18/1985
  • Status: Expired due to Term
First Claim
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1. A method of pre-processing an acoustic waveform prior to transmission to reduce the peak-to-RMS ratio of the waveform, the method comprising:

  • a. sampling the waveform to obtain a series of discrete samples and constructing therefrom a series of frames, each frame spanning a plurality of samples;

    b. analyzing each frame of samples to extract a set of variable frequency components having individual amplitudes and phases;

    c. removing the natural phase dispersion from said variable frequency components and substituting therefor a desired phase dispersion;

    d. tracking said components from one frame to a next frame; and

    e. interpolating the values of the components from the one frame to the next frame to obtain a parametric representation of the waveform whereby a synthetic waveform having a flattened time-domain envelope can be constructed by generating a set of sine waves corresponding to the interpolated values of the parametric representation.

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