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Ultrasonic transducer and current loop transmitter

  • US 4,823,600 A
  • Filed: 11/05/1987
  • Issued: 04/25/1989
  • Est. Priority Date: 11/05/1987
  • Status: Expired due to Term
First Claim
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1. A remote ultrasonic sensor and control system comprising:

  • at least one remote ultrasonic sensor means for detecting ultrasonic vibrations in its vicinity and converting them into an electrical signal, said sensor means having a variable gain which can be changed in discrete steps according to a control signal;

    a central control means for analyzing the electrical signal from the sensor means and for generating the control signal for the sensor means; and

    a current loop transmission means connecting said sensor means and central control means, said current loop transmission means including a first current loop continuously delivering the control signals to said sensor means as discrete current levels and a second current loop continuously delivering the electrical signal from said sensor means as a current level.

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