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

A system and method are disclosed 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, themore » final possibility will be successful because a clear time-slot channel will be available. 5 figs.« less
Inventors:
Issue Date:
OSTI Identifier:
415749
Assignee:
Univ. of California, Oakland, CA (United States) PTO; SCA: 055001; PA: EDB-97:012598; SN: 97001714574
Patent Number(s):
US 5,591,951/A/
Application Number:
PAN: 8-542,214
Contract Number:
W-7405-ENG-48
Resource Relation:
Other Information: PBD: 7 Jan 1997
Research Org:
University of California
Country of Publication:
United States
Language:
English
Subject:
05 NUCLEAR FUELS; IDENTIFICATION SYSTEMS; INFORMATION RETRIEVAL; RADIOWAVE RADIATION; SEMICONDUCTOR STORAGE DEVICES; DATA TRANSMISSION; SECURITY