05453747 is referenced by 140 patents and cites 3 patents.

A method of communicating between an interrogator (10) and at least a first and second transponder (12). The transponders (12)are separately located within a first and a second vehicle (20) travelling within a first and a second traffic lane, respectively. The method has the steps of providing a first and a second LF antenna (16) associated with and proximity to a first and a second traffic lane, respectively. From each of the first and second LF antennas (16) a continuous LF subcarrier is transmitted to serve as a clock signal for each antenna's associated transponder (12). Initially, a wake-up signal is sent by each of the LF antennas (16) to its associated transponder (12). Following the wake-up signal, a unique lane code is sent by each of the LF antennas (16) to its associated transponder (12). The transponder (12) stores its unique lane code in its memory (70). The transponder then sends a UHF response in a pre-determined time period depending on the unique lane code stored in each of the transponders (12). The time period in which the transponder (12) sends its UHF response is unique to that transponder (12) so that interference between responding transponders (12) is avoided. Other devices, systems and methods are also disclosed.

Title
Transponder systems for automatic identification purposes
Application Number
83808
Publication Number
5453747
Application Date
July 18, 1994
Publication Date
September 26, 1995
Inventor
Herbert Meier
Moosburg
DE
Anne Tip
Overdinkel
NL
Loek D Hont
Almelo
NL
Agent
Richard L Donaldson
James C Kesterson
Brian C McCormack
Assignee
Texas Instruments Holland
NL
Texas Instruments Deutschland
DE
IPC
G01S 13/74
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