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Method and apparatus for analyzing traffic and a sensor therefor

  • US 5,748,108 A
  • Filed: 01/10/1997
  • Issued: 05/05/1998
  • Est. Priority Date: 01/10/1997
  • Status: Expired due to Term
First Claim
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1. An apparatus for detecting vehicles passing a fixed position, the apparatus comprising:

  • a first magnetic field detector for generating a first analog signal indicative of changes in magnetic field strength adjacent the first detector in response to a vehicle passing thereby;

    a differentiating circuit for differentiating the first analog signal and for producing a first output that changes binary states in response to detecting a predetermined change in the differentiated first analog signal;

    a counter which accumulates values at a predetermined rate; and

    a processor for storing a counter value for each change in the binary state of the first output of the differentiating circuit, for converting into a first time series profile the stored counter values corresponding to the changes in the first output of the differentiating circuit and for accumulating and storing a count of passing vehicles.

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