"Dual technology intruder detection system with sensitivity adjustment after ""default"""
US5077548A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 29, 1990 |
| Grant date | Dec 31, 1991 |
| Priority date | — |
| Expiry date | Jun 29, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B13/2494
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A dual-tech intruder detection system includes a pair of intruder-detecting subsystems, each functioning to detect intrusion by a technology different from the other, and apparatus for activating an alarm in response to both subsystems detecting intrusion within a predetermined time interval. A supervisory circuit serves to detect a malfunction in one of the subsystems. Default apparatus, responsive to the output of the supervisory circuit, causes the alarm activating apparatus to activate an alarm in response to the still-functioning subsystem's detection of intrusion. To reduce false alarms from the still-functioning subsystem, circuit apparatus are provided for reducing the sensitivity of such subsystem in response to the output of the supervisory circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.