Divergent code generator and method
First Claim
1. A method for generating a divergent code, said divergent code, for example, for ensuring that a population of transponders in devices such as RF tags having nominally identical apparatus for generating a delay will generate different delays, said apparatus being responsive to said divergent code, said delay being introduced prior to responding to an interrogation signal for polling said population of transponders, said method comprising steps of:
- generating a first bit stream from a number generator;
combining, via a combiner having a first input coupled to an output of a memory, a second input coupled to an output of said number generator and an output coupled to an input of said number generator, a predetermined number from said memory with said first bit stream to provide a second bit stream; and
feeding said second bit stream into a feedback port of said number generator.
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Accused Products
Abstract
A method and corresponding apparatus (10) for generating a pseudo-random number. The method has steps of generating a first bit stream from a number generator (16, 35), combining a predetermined number with the first bit stream to provide a second bit stream and feeding the second bit stream into a feedback port (32) of the number generator (16, 35).
97 Citations
27 Claims
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1. A method for generating a divergent code, said divergent code, for example, for ensuring that a population of transponders in devices such as RF tags having nominally identical apparatus for generating a delay will generate different delays, said apparatus being responsive to said divergent code, said delay being introduced prior to responding to an interrogation signal for polling said population of transponders, said method comprising steps of:
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generating a first bit stream from a number generator; combining, via a combiner having a first input coupled to an output of a memory, a second input coupled to an output of said number generator and an output coupled to an input of said number generator, a predetermined number from said memory with said first bit stream to provide a second bit stream; and feeding said second bit stream into a feedback port of said number generator. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An apparatus for generating a number, said apparatus comprising:
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a memory for storing a predetermined number; a number generator; and a combiner having a first input coupled to an output of said memory, a second input coupled to an output of said number generator and an output coupled to an input of said number generator. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. An apparatus comprising:
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a control device having a capability for sending a first message and receiving second messages; and a plurality of remote devices having a capability for receiving said first message and for transmitting said second messages, each of said plurality of remote devices comprising; a memory for storing a predetermined number; a number generator; and a combiner having a first input coupled to an output of said memory, a second input coupled to an output of said number generator and an output coupled to an input of said number generator. - View Dependent Claims (17, 18, 19, 20)
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21. An apparatus comprising:
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a control device having a capability for sending a first message and receiving second messages; and a plurality of remote devices having a capability for receiving said first message and for transmitting said second messages, each of said plurality of remote devices comprising; a memory for storing a predetermined number, wherein said predetermined number is a serial number identifying a particular remote device of said plurality of remote devices; a number generator comprising a linear feedback shift register configured to provide a maximal length sequence; a combiner having a first input coupled to an output of said memory, a second input coupled to an output of said number generator and an output coupled to an input of said number generator; and wherein said second messages are transmitted at a time, said time chosen in response to a number obtained from said number generator, said time denoting a time interval measured from a time of receipt of said first message.
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22. An apparatus comprising:
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a control device having a capability for sending a first message and receiving second messages; and a plurality of remote devices having a capability for receiving said first message and for transmitting said second messages, each of said plurality of remote devices comprising; memory means for storing a predetermined number; means for number generation, said number generation means having an input port and an output port, said number generation means for providing a first bit stream comprising a random number at said input port; and means for combining, said combining means having a first input coupled to an output of said memory and a second input coupled to an output of said number generation means, said combining means for combining said predetermined number with said first bit stream to provide a second bit stream at an output coupled to said input port. - View Dependent Claims (23, 24, 25, 26, 27)
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Specification