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Ultrasonic temperature measuring apparatus

  • US 5,360,268 A
  • Filed: 11/01/1993
  • Issued: 11/01/1994
  • Est. Priority Date: 11/02/1992
  • Status: Expired due to Fees
First Claim
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1. A temperature measuring apparatus for measuring the temperature of a medium according to the propagation time of ultrasonic waves propagated for a predetermined distance through the medium, comprising:

  • transmission means for transmitting ultrasonic waves having a fixed frequency at predetermined timing;

    reception means for receiving the ultrasonic waves and providing a received signal;

    means for detecting, in response to the received signal, a delay time between the transmission and reception of the ultrasonic waves;

    means for calculating an integral wave number according to the delay time and a period of the ultrasonic waves;

    means for detecting a phase difference between the transmitted and received ultrasonic waves by modulating the received signal with a frequency sufficiently higher than the frequency of the ultrasonic waves; and

    means for calculating the propagation time of the ultrasonic waves according to the wave number and phase difference, and according to the propagation time, the temperature of the medium.

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