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Title: System and method for simultaneously collecting serial number information from numerous identity tags

A system and method for simultaneously collecting serial number information reports from numerous colliding coded-radio-frequency identity tags. Each tag has a unique multi-digit serial number that is stored in non-volatile RAM. A reader transmits an ASCII coded "D" character on a carrier of about 900 MHz and a power illumination field having a frequency of about 1.6 Ghz. A one MHz tone is modulated on the 1.6 Ghz carrier as a timing clock for a microprocessor in each of the identity tags. Over a thousand such tags may be in the vicinity and each is powered-up and clocked by the 1.6 Ghz power illumination field. Each identity tag looks for the "D" interrogator modulated on the 900 MHz carrier, and each uses a digit of its serial number to time a response. Clear responses received by the reader are repeated for verification. If no verification or a wrong number is received by any identity tag, it uses a second digital together with the first to time out a more extended period for response. Ultimately, the entire serial number will be used in the worst case collision environments; and since the serial numbers are defined as being unique, the final possibilitymore » will be successful because a clear time-slot channel will be available.« less
Inventors:
 [1]
  1. (Manteca, CA)
Issue Date:
OSTI Identifier:
870775
Assignee:
Regents of University of California (Oakland, CA) LLNL
Patent Number(s):
US 5591951
Contract Number:
W-7405-ENG-48
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Country of Publication:
United States
Language:
English
Subject:
method; simultaneously; collecting; serial; information; numerous; identity; tags; reports; colliding; coded-radio-frequency; tag; unique; multi-digit; stored; non-volatile; reader; transmits; ascii; coded; character; carrier; 900; mhz; power; illumination; field; frequency; ghz; tone; modulated; timing; clock; microprocessor; thousand; vicinity; powered-up; clocked; looks; interrogator; digit; time; response; responses; received; repeated; verification; wrong; digital; extended; period; ultimately; entire; worst; collision; environments; defined; final; possibility; successful; time-slot; channel; available; extended period; simultaneously collecting; collecting serial; identity tags; timing clock; identity tag; /340/235/