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Differential AC anemometer

  • US 5,263,380 A
  • Filed: 02/18/1992
  • Issued: 11/23/1993
  • Est. Priority Date: 02/18/1992
  • Status: Expired due to Term
First Claim
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1. An apparatus for providing an airflow output signal indicative of a measurement of airflow, comprising:

  • a sensor including a heater, an upstream detector and a downstream detector;

    means for exciting the heater to generate propagating heat signals that are received by the upstream and downstream detectors;

    first signal means for providing a first output signal responsive to the propagating heat signals received by the first detector;

    second signal means providing a second output signal responsive to the propagating heat signals received by the downstream detector;

    means for subtracting the first and second signals to obtain a difference signal; and

    means for providing the airflow output signal responsive to the difference signal, the airflow output signal comprising a first component and a second component, the first component representative of a magnitude difference of the first and second output signals and the second component representative of a phase difference between the first and second output signals wherein the airflow output signal is indicative of a measure of mass airflow past the sensor, thereby providing increased sensor sensitivity.

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