Transponder for proximity identification system
First Claim
1. A transponder for use in an object identification system including an interrogator which transmits a continuous interrogation signal and detects a responsive identification signal transmitted by the transponder, said transponder comprising:
- means for receiving and detecting said interrogation signal;
means, responsive to receipt of said interrogation signal, for continuously producing an identification signal having a frame with a fixed number of binary bits including a start bit corresponding to a first binary value, an identification data portion of a specified number of bits less than one half of said fixed number of bits, and a following synchronization portion including first, second and third consecutive bits of alternating binary values, with said first and said third bits being of said first binary value and said second bit being of a second binary value, followed by a sequence of bits which are all of said second binary value to complete said frame;
means for producing a carrier signal; and
means for modulating said carrier signal with said identification signal and for transmitting the modulated carrier signal.
5 Assignments
0 Petitions
Accused Products
Abstract
A transponder for use in an object identification system including an interrogator which transmits a continuous interrogation signal and detects a responsive identification signal transmitted by the transponder. The transponder receives and detects the interrogation signal and, in response to receipt of the interrogation signal, produces a repeating identification signal having a fixed number of binary bits consisting of an identification data portion of a specified number of consecutive bits less than one half of the fixed number of bits, and a synchronization pattern of consecutive bits consisting of first, second and third bits of alternating binary values, a consecutive sequence of a plurality of bits which are all of the same binary value as the second bit, and a single bit of the same binary value as the first and third bits. The identification signal is modulated onto a carrier signal and transmitted. Preferably, the first, second and third bits and the sequence of a plurality of bits constitute one half of the fixed number of binary bits of the identification signal, with the binary value of the first bit being a binary 1.
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Citations
14 Claims
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1. A transponder for use in an object identification system including an interrogator which transmits a continuous interrogation signal and detects a responsive identification signal transmitted by the transponder, said transponder comprising:
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means for receiving and detecting said interrogation signal; means, responsive to receipt of said interrogation signal, for continuously producing an identification signal having a frame with a fixed number of binary bits including a start bit corresponding to a first binary value, an identification data portion of a specified number of bits less than one half of said fixed number of bits, and a following synchronization portion including first, second and third consecutive bits of alternating binary values, with said first and said third bits being of said first binary value and said second bit being of a second binary value, followed by a sequence of bits which are all of said second binary value to complete said frame; means for producing a carrier signal; and means for modulating said carrier signal with said identification signal and for transmitting the modulated carrier signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A transponder for use in an object identification system including an interrogator which transmits a continuous interrogation signal and detects a responsive identification signal transmitted by the transponder, said transponder comprising:
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means for receiving and detecting said interrogation signal; means, responsive to receipt of said interrogation signal, for producing a repeating identification signal having a fixed number of binary bits consisting of an identification data portion of a specified number of consecutive bits less than one half of said fixed number of bits, and a synchronization pattern of consecutive bits consisting of first, second and third bits of alternating binary values, a consecutive sequence of a plurality of bits which are all of the same binary value as said second bit, and a single bit of the same binary value as said first and third bits; means for producing a carrier signal; and means for modulating said carrier signal with said identification signal and for transmitting the modulated carrier signal. - View Dependent Claims (11, 12)
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13. In a method of identifying an object comprising the steps of transmitting a continuous interrogation signal from an interrogator installation, detecting said interrogation signal at a transponder in the proximity of said interrogator installation, and producing an encoded identification signal in the transponder and transmitting same to a reader at the interrogator installation;
- the improvement wherein;
said step of producing an encoded identification signal comprises continuously generating an identification signal having a fixed number of binary bits consisting of an identification data portion of a specified number of consecutive bits less than one half of said fixed number of bits, and a synchronization pattern of consecutive bits consisting of first, second and third bits of alternating binary values, a consecutive sequence of a plurality of bits which are all of the same binary value as said second bit, and a single bit of the same binary value as said first and third bits. - View Dependent Claims (14)
- the improvement wherein;
Specification