EP 0556910 A1 19930825 - A remote identification system comprising passive identification devices.
Title (en)
A remote identification system comprising passive identification devices.
Title (de)
Fernidentifikationssystem mit passiver Identifikationsvorrichtung.
Title (fr)
Système d'identification à distance comprenant des dispositifs passifs d'identification.
Publication
Application
Priority
NL 9200304 A 19920219
Abstract (en)
A system for remote identification of objects, comprising a transmitter, a receiver and a set of passive identification devices associated with the objects, which operate as a transponder for a receiver in response to operation of the transmitter. Each passive identification device has an LC-resonance circuit and a quartz crystal inductively coupled thereto. It is possible to use one quartz crystal as well as several quartz crystal having different frequencies, which are connected in parallel. Within a set of passive identification devices it is possible to use passive identification devices each containing one quartz crystal, said quartz cyrstals either having one and the same frequency or different frequencies, or passive identification devices containing 1, 2 and more quartz crystals having different frequencies, or a constant number of quartz crystals having different frequencies. The transmitter and the receiver are switched, whereby a time delay is provided between switching off of the transmitter and switching on of the receiver. The transmitter transmits a transmission signal at every frequency of the quartz crystals used, and the receiver demodulates in as many channels and performs a matched filter operation, after which correlation is carried out for final identification. <IMAGE>
IPC 1-7
IPC 8 full level
G08B 13/24 (2006.01)
CPC (source: EP)
G08B 13/2414 (2013.01); G08B 13/2417 (2013.01); G08B 13/2431 (2013.01); G08B 13/2462 (2013.01)
Citation (search report)
- [Y] EP 0131440 A1 19850116 - MINNESOTA MINING & MFG [US]
- [Y] WO 8800785 A1 19880128 - BI INC [US]
Designated contracting state (EPC)
AT BE CH DE DK ES FR GB GR IE IT LI LU MC NL PT SE
DOCDB simple family (publication)
DOCDB simple family (application)
EP 93200396 A 19930215; NL 9200304 A 19920219