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Parallel processing pitch detector

  • US 4,879,748 A
  • Filed: 08/28/1985
  • Issued: 11/07/1989
  • Est. Priority Date: 08/28/1985
  • Status: Expired due to Fees
First Claim
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1. A pitch detector system for human speech comprising:

  • means for storing a predetermined number of evenly spaced samples of instantaneous amplitude of said speech as a speech frame;

    means for generating residual samples from said speech samples;

    a plurality of identical means each responsive to an individual predetemined portion of said residual samples of said frame for estimating a pitch value of said frame;

    another plurality of identical means each responsive to an individual predetermined portion of said speech samples of said frame for estimating a pitch value of said frame;

    means for calculating a final pitch value from the estimated pitch values from each of said plurality and said other plurality of estimating means wherein an unvoiced speech frame is indicated by said calculated pitch value being equal to a predefined value and a voiced frame is indicated by said calculated pitch value being equal to a value other than said predefined value;

    said calculating means comprises means responsive to all of said estimated pitch values having a value different than said predefined value for setting said calculated pitch value equal to the arithmetic average of a subset of said estimated pitch values, said subset comprising all of said estimated pitch values except the lowest magnitude value and the highest magnitude value;

    means for constraining said final pitch value so that the calculated pitch value is consistent with calculated pitch values from previous frames;

    said constraining means comprises means responsive to a first sequence of frames comprising a voiced frame and an unvoiced frame and a second voiced frame for generating a new calculated pitch value having an arithmetic relationship to the calculated pitch values of the frames of said first sequence;

    said generating means comprises a new pitch value generating means responsive to a second sequence of frames comprising an unvoiced frame and a voiced frame and a second unvoiced frame for generating a new calculated value indicating an unvoiced frame; and

    said new pitch value generating means further reponsive to a third sequence of frames comprising a voiced frame and a second voiced frame and a third voiced frame for generating a new calculated pitch value having an arithmetic relationship to the calculated pitch values of the frames of said third sequence.

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