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Optical sensor arrangement for presence detection with variable pulse repetition frequency

  • US 5,416,316 A
  • Filed: 01/10/1994
  • Issued: 05/16/1995
  • Est. Priority Date: 12/14/1992
  • Status: Expired due to Fees
First Claim
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1. The method of operating an optical sensor arrangement for detecting articles present in a monitored region, said method comprising the steps of:

  • emitting a plurality of light signals from a light transmitter into said monitored region, each of said light signals comprising a number of pulses, forming a pulse sequence, which follow each other at a pulse repetition frequency;

    varying said pulse repetition frequency between any two successive emitted light signals;

    receiving said light signals at a light receiver as received light signals;

    processing said received light signals in a received signal processing stage, said received signal processing stage comprising a filter arrangement permeable to frequency components of the pulse sequence;

    producing an article detection signal when said received light signals indicates the presence of an article in said monitored region.

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