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US 4,546,241 AGranted
Electronic proximity identification system
OwnerCharles A. Waltoninventor
Life of this patent
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Abstract
An electronic identification and recognition system including a portable card having a circuit therein for generating and transmitting and identifying signal comprising predetermined frequency pulses. The card functions in cooperation with a reader which radiates a radio frequency carrier signal received by an antenna in the card. This signal is used both to power the circuit of the card and to provide the basic frequency signal which is modified to generate secondary frequency signals which are transmitted back to the reader in a predetermined sequence identifying the card.
Claims8
An electronic identification system comprising:
- a reader including means to generate, radiate and identify a carrier frequency signal;
- and
- an identification card having an electronic circuit and comprising;
- means to receive said carrier frequency signal radiated by said reader;
- means to generate power from said carrier frequency signal to energize said card electronic circuit;
- a counter to receive and generate secondary radio frequency signals by dividing said carrier frequency signal;
- a data memory for recording an identification code identifying said card;
- means to access said data memory and select said secondary radio frequency signals responsive to said identification code;
- and
- an antenna connected to receive and radiate said selected secondary radio frequency signals to said reader to allow said reader to identify said card.
7 more elements
Dependencies are inferred from the claim text.