Electronic identification system confirming valid code
First Claim
1. An identification system comprising:
- an interrogator; and
a plurality of transponders wherein;
the interrogator comprises;
a transmitter for transmitting an interrogation signal to the transponders,a receiver for receiving response signals from the transponders,a processor for identifying the transponders from data in the response signals, andmeans for confirming that a valid code from any one of the transponders is received and for modifying the interrogation signal to indicate confirmation of the valid code, the modifying of the interrogation signal being in response to and just after successful identification of the one of the transponders and being for a predetermined period after successfully identifying the one of the transponders, the predetermined period of time being shorter than a length of a transponder transmission;
each of the transponders comprises;
a receiving antenna for receiving the interrogation signal,a code generator,a transmitting antenna,a modulator connected to the code generator, so that upon receipt of the interrogation signal the transponder transmits a response signal containing data which identifies the transponder,means for repeating a transmission of the response signal at random or pseudo-random intervals to increase a probability of successful reception thereof by the interrogator, andmeans for sensing a modification in the interrogation signal and ceasing transmission of the response signal in response thereto.
2 Assignments
0 Petitions
Accused Products
Abstract
An identification system having an interrogator and a number of transponders. The interrogator includes a transmitter for transmitting an interrogation signal to the transponder, and a receiver for receiving a response signal from the transponder. A micro-processor identifies the transponder from data in the response signal. Each transponder includes a receiving antenna for receiving the interrogation signal, a code generator, a transmitting antenna, and a modulator connected to the code generator. On receipt of the interrogation signal the transponder repeatedly transmits a response signal containing data which identifies the transponder. The interrogator detects successful identification of any transponder and briefly interrupts the interrogation signal to indicate the successful identification. Each transponder includes a logic circuit responsive to a respective interruption in the interrogation signal to cease transmission of its own response signal.
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Citations
25 Claims
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1. An identification system comprising:
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an interrogator; and a plurality of transponders wherein; the interrogator comprises; a transmitter for transmitting an interrogation signal to the transponders, a receiver for receiving response signals from the transponders, a processor for identifying the transponders from data in the response signals, and means for confirming that a valid code from any one of the transponders is received and for modifying the interrogation signal to indicate confirmation of the valid code, the modifying of the interrogation signal being in response to and just after successful identification of the one of the transponders and being for a predetermined period after successfully identifying the one of the transponders, the predetermined period of time being shorter than a length of a transponder transmission; each of the transponders comprises; a receiving antenna for receiving the interrogation signal, a code generator, a transmitting antenna, a modulator connected to the code generator, so that upon receipt of the interrogation signal the transponder transmits a response signal containing data which identifies the transponder, means for repeating a transmission of the response signal at random or pseudo-random intervals to increase a probability of successful reception thereof by the interrogator, and means for sensing a modification in the interrogation signal and ceasing transmission of the response signal in response thereto. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A transponder comprising:
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a receiving antenna for receiving an interrogation signal; a code generator; a transmitting antenna; a modulator connected to the code generator; means for transmitting a response signal containing data which identifies the transponder; and means for controlling a transmission to cause the transmission of a response signal to be repeated at random or pseudo-random intervals to increase a probability of successful reception thereof by an interrogator, the means for controlling being responsive to a modification of the interrogation signal for ceasing transmission of the response signal in response to the modification of the interrogation signal, the modification of the interrogation signal being in response to and just after successful identification of the transponder and being for a predetermined period of time being shorter than a length of a transponder transmission. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. An interrogator for identifying a plurality of transponders, comprising:
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a transmitter for transmitting an interrogation signal to the transponders; a receiver for receiving response signals from the transponders, the response signals from the transponders being repeated at random or pseudo-random intervals; a processor for identifying a transponder from data in the response signal; and means for modifying the interrogation signal to indicate that a valid code of any one of the transponders is received by the interrogator, the modifying of the interrogation signal being in response to and just after successful identification of the transponder and being for a predetermined time after successfully identifying the one of the transponders, the predetermined time being shorter than a length of a transponder transmission. - View Dependent Claims (19)
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20. A transponder for use with an interrogator, the interrogator comprising:
- a transmitter for transmitting an interrogation signal to a plurality of transponders, the interrogation signal being modulated with a code corresponding to data stored in at least one of the transponders;
a receiver for receiving response signals from the transponders, the response signals from the transponders being repeated at random or pseudo-random intervals;
a processor for identifying a transponder from data in the response signal;
means for modifying the interrogation signal to indicate that a valid code of any one of the transponders is received by the interrogator, the modifying of the interrogation signal being in response to and just after successful identification of the transponder and being for a predetermined time after successfully identifying the one of the transponders, the predetermined time being shorter than a length of a transponder transmission, the transponder comprising;means for sensing a modification of the interrogation signal. - View Dependent Claims (21)
- a transmitter for transmitting an interrogation signal to a plurality of transponders, the interrogation signal being modulated with a code corresponding to data stored in at least one of the transponders;
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22. An integrated circuit for use in a transponder, comprising:
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means for generating a response signal at random or pseudo-random intervals, in response to an interrogation signal, the response signal containing data which identifies the transponder; and means for controlling arranged to cause repeated generation of the response signal, the means for controlling being responsive to a modification in the interrogation signal for ceasing generation of the response signal in response to the modification of the interrogation signal, the means for controlling including means for detecting a modification of the interrogation signal of a predetermined period, the modification of the interrogation signal being in response to and just after successful identification of the transponder and the predetermined period being shorter than a length of a transponder transmission. - View Dependent Claims (23, 24, 25)
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Specification