Patent · US Expired

Intrusion detection system

US4622541A · kind A · utility

30Cited by
8References
21Claims
0Family size

Assignee

Inventor

Key dates

Filing dateJan 9, 1984
Grant dateNov 11, 1986
Priority date—
Expiry dateJan 9, 2004

Classification

  • Technology area (CPC G)Physics
  • CPC primaryG08B13/1663
  • WIPO fieldControl
  • WIPO sectorInstruments

Abstract

There is disclosed an intrusion detection system employing vibration sensors which are arranged in a series loop consisting of first and second wires and which loop is terminated by a terminating impedance. Coupled to the wires is a processing circuit which supplies a square wave biasing waveform for the loop and a DC voltage determined by the terminating impedance. By detecting the magnitude of the DC level, the processor can determine if the loop has been opened or shorted or if any one of the sensors in the loop has been activated due to an intrusion. Thus the system described employs two wires for supplying both power and sensing of output signals from the loop being monitored.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.