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Intrusion detection devices employing multiple scan zones

  • US 3,958,118 A
  • Filed: 02/03/1975
  • Issued: 05/18/1976
  • Est. Priority Date: 02/03/1975
  • Status: Expired due to Term
First Claim
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1. For use in an intrusion monitoring device of the type which has a group of radiation detectors, each of which monitors a segment of a primary scan zone, and which produces an alarm signal when energy being emitted from bodies as they move among said segments is received by more than one of said detectors within a pre-determined time span, wherein no two adjacent segments are associated with the same detectora scan zone multiplier device for increasing the scan zone capability of said monitoring device to cover at least one secondary zone in addition to said primary scan zone comprisingmeans for directing radiation energy being emitted from bodies in each of said secondary scan zones to said detectors whereby each of said zones will have at least one segment thereof monitored by a detector, and wherein no two adjacent segments within any of said secondary zones or between any of said secondary zones or between any of said secondary zones and said primary zone are monitored by the same detector.

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