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NCJ Number
Essecome International Volume: 3 Issue: 6 Dated: (November 1992) Pages: 26-28
H Berner
Date Published
3 pages
Intelligence may be designed into a security system either in the detectors or in the control units. The need for high sensitivity and decentralization of intelligence dictates the best approach is to design intelligent detectors.
The signal in an ultrasonic detector can identify the speed of the object, the direction of movement, the distance the object has moved, the distance between object and detector, and the number of changes in direction. The signal of a passive infrared detector depends on the temperature difference between target and ambient, wavelength of the IR, and angular target speed and distance. The MATCHTEC detector combines ultrasonic and passive infrared detection and has sufficient intelligence to compare what it sees with what it hears. The detector's logic processor looks at all the relevant criteria from both detection systems and judges the results as an entity. The detector keeps the nuisance alarm rate low by understanding when a certain signal is likely to have been sent by an intruder under specific circumstances.