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Parametric audio system

  • US 7,391,872 B2
  • Filed: 01/11/2001
  • Issued: 06/24/2008
  • Est. Priority Date: 04/27/1999
  • Status: Expired due to Term
First Claim
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1. A parametric audio system for generating at least one airborne audio beam, comprising:

  • at least one audio signal source configured to provide at least one audio signal;

    at least one signal conditioner configured for receiving the at least one audio signal and for nonlinearly processing the audio signal to provide at least one pre-distorted signal;

    a modulator configured to receive the pre-distorted signal and to convert the pre-distorted signal into ultrasonic frequencies; and

    an acoustic transducer array including plurality of acoustic transducers, the array being configured to receive the converted signal and to project the converted signal through the air along a selected path, thereby inverting distortion in the projected signal and regenerating the audio signal along at least a portion of the selected path with reduced net distortion,wherein the acoustic transducer array has a bandwidth greater than 5 kHz, andwherein the acoustic transducer array further includes;

    a backplate having a surface and a succession of depressions formed on the surface, the respective depressions having different depths; and

    a membrane with at least one conductive surface adjacently disposed along the backplate,wherein the membrane and the succession of depressions define the plurality of acoustic transducers, each of the plurality of acoustic transducers having an associated center frequency determined at least in part by the depth of the respective depression;

    wherein the depressions formed on the surface of the backplate alternate in succession between at least one depression having at least one first specified depth and at least one depression having at least one second specified depth, andwherein the spacing between the center frequencies determined at least in part by the at least one first specified depth and the at least one second specified depth is sufficient to obtain an aggregate frequency response of the acoustic transducer array having the bandwidth greater than 5 kHz.

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