05500651 is referenced by 147 patents and cites 11 patents.

A system and method for communicating between an identification reader 12 and a transponder unit 10 is disclosed herein. A first interrogation signal is transmitted from the reader 12. This first interrogation signal having a first read range. A first response signal is then received at the reader 12 after which a second interrogation signal is transmitted from the reader 12. The second interrogation signal has a second read range which is different than said first read range. The read range can be varied by varying either the amplitude or duration of the power level of the interrogation signal. A second response signal is then received at the reader 12. These consecutive responses are then compared determine a correct response signal which can be displayed.

Title
System and method for reading multiple RF-ID transponders
Application Number
8/265545
Publication Number
5500651
Application Date
June 24, 1994
Publication Date
March 19, 1996
Inventor
Josef Schuermann
Oberhummel
DE
Agent
Richard L Donaldson
Ira S Matsil
Thomas G Eschweiler
Assignee
Texas Instruments Incorporated
TX, US
IPC
G01S 13/75
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