Electronic article surveillance system utilizing synchronous integration
US4812822A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 31, 1987 |
| Grant date | Mar 14, 1989 |
| Priority date | — |
| Expiry date | Aug 31, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B13/2488
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
An electronic article surveillance system employs a resonant tag attached to an article being protected. An interrogation transmitter whose transmission frequency is periodically swept through the resonant frequency of the tag is positioned near an exit of the protected area. The resonant tag is periodically energized by the transmitter as the transmitter frequency passes through the resonant frequency of the tag to cause the tag to emit a periodic tag signal at the sweep rate of the transmitter. The tag signal is received by a receiver that generates an alarm upon the detection of a tag signal. The receiver employs synchronous integration in the form of a dual channel synchronous video integrator to independently process positive and negative pulses of the tag signal in order to differentiate the tag signal from extraneous signals and noise.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.