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Apparatus for monitoring opening of sealed containers

  • US 5,939,982 A
  • Filed: 06/08/1998
  • Issued: 08/17/1999
  • Est. Priority Date: 06/09/1997
  • Status: Expired due to Term
First Claim
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1. Apparatus for monitoring opening of an electromagnetically shielded enclosure, comprising a radio receiver unit having at least one antenna for reception of radio signals, the receiver unit to be housed within the enclosure and comprising means for scanning a predetermined band of radio frequencies, periodically or continuously, and detecting a predetermined radio signal level;

  • and means operable in dependence upon such radio signal level detection to generate a signal indicating opening of the enclosure.

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