0494114-A2 is referenced by 88 patents and cites 5 patents.

An identification system comprises an interrogator and a number of transponders. The interrogator includes a transmitter (10) for transmitting an interrogation signal to the transponder, and a receiver (16,18,20,22) for receiving a response signal from the transponder. A micro-processor (28) identifies the transponder from data in the response signal. Each transponder comprises a receiving antenna (30) for receiving the interrogation signal, a code generator (36), a transmitting antenna (32), and a modulator (40) connected to the code generator. On receipt of the interrogation signal the transponder repeatedly transmits a response signal containing data which identifies the transponder. The interrogator detects successful identification of any transponder and briefly interrupts the interrogation signal to indicate the successful identification.; Each transponder includes a logic circuit (42) responsive to a respective interruption in the interrogation signal to cease transmission of its own response signal.

Title
Electronic identification system.
Application Number
EP19920300041 19920103
Publication Number
0494114 (A2)
Application Date
January 3, 1992
Publication Date
July 8, 1992
Inventor
Lenarcik Andrzej
ZA
Marsh Michael John Camille
ZA
Assignee
Csir
ZA
IPC
G07C 09/00
G06K 07/08
H04L 01/08
G08G 01/017
G08B 21/00
G08B 13/14
G07C 09/00
G07B 15/00
G06K 17/00
G06K 07/00
G01S 13/00
H04L 01/08
G08G 01/017
G08B 21/02
G08B 13/14
G07C 09/00
G07B 15/00
G06K 17/00
G06K 07/00
G01S 13/75
G01S 13/74
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