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HEARING TESTING METHOD AND AUDIOMETER

  • US 3,799,146 A
  • Filed: 10/06/1971
  • Issued: 03/26/1974
  • Est. Priority Date: 10/06/1971
  • Status: Expired due to Term
First Claim
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1. An instrument for the testing of the hearing of a subject, including means to make audible to the subject a series of tones at selected frequencies and loudness levels;

  • a contact adapted to be worn by the subject to detect his brain waves;

    an electroencephalograph amplifier having an input and output whose input is connected to said contact;

    a signal detector having an input and an output and whose input is connected to said amplifier output, said signal detector comprising an absolute value circuit having its input connected to the input of said signal detector;

    a polarity shifting circuit whose input is connected to the output of said absolute value circuit, an integrator whose input is connected to the output of said shifting circuit, and a comparator whose input is connected to said integrator and whose output is connected to the output of said signal detector;

    a single-input multi-output switch whose input is connected to said signal detector output;

    a plurality of memory section counters connected to said switch outputs;

    a display device connected to said memory sections; and

    a programmer connected to said tone means and to said switch to direct the evoked responses at each tone to one of the memory sections.

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