US5606322A — Divergent code generator and method

Claim 1

Independent Claim 144 words

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.

Claim 2

Independent Claim 144 words

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.

Claim 3

Dependent Claim 26 words

A method as claimed in claim 1, wherein said generating step comprises a step of generating a first bit stream from a linear feedback shift register.

Claim 4

Dependent Claim 96 words

A method as claimed in claim 1, wherein said combining step includes steps of: rotating said predetermined number through a shift register comprising said memory, said shift register having a series of N many shift register cells coupled to form a continuous closed loop, wherein a number N of cells in said shift register is greater than or equal to a number of bits comprising said predetermined number and at least one of said N many shift register cells includes an output tap; and adding a signal from said output tap to said first bit stream.

Claim 5

Dependent Claim 25 words

A method as claimed in claim 1, wherein said combining step includes a step of exclusive ORing said predetermined number with said first bit stream.

Claim 6

Dependent Claim 32 words

A method as claimed in claim 1, wherein said generating step includes a step of generating said first bit stream from a linear feedback shift register configured to provide a divergent code.

Claim 7

Dependent Claim 39 words

A method as claimed in claim 1, wherein said combining step includes a step of combining a unique serial number chosen from a predetermined set of serial numbers with said first bit stream to provide said second bit stream.

Claim 8

Dependent Claim 34 words

A method as claimed in claim 1, wherein said step of generating a first bit stream from a number generator includes a step of generating a first bit stream from a divergent code generator.

Claim 9

Independent Claim 55 words

An apparatus for generating a number, said apparatus 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.

Claim 10

Independent Claim 55 words

An apparatus for generating a number, said apparatus 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.

Claim 11

Dependent Claim 23 words

An apparatus as claimed in claim 8, wherein said number generator comprises a linear feedback shift register configured to provide a pseudo-random number.

Claim 12

Dependent Claim 21 words

An apparatus as claimed in claim 9, wherein said linear feedback shift register is configured to provide a maximal length sequence.

Claim 13

Dependent Claim 34 words

An apparatus as claimed in claim 9, wherein: said number generator comprises a pseudorandom number generator including M many cells; and wherein M is an integer in a range of from five to twenty.

Claim 14

Dependent Claim 60 words

An apparatus as claimed in claim 8, wherein said memory comprises: a shift register including N many cells; wherein said output of said memory is coupled to an output of an N th cell of said shift register; and wherein an input of a first cell of said shift register is coupled to said output of said N th cell.

Claim 15

Dependent Claim 14 words

An apparatus as claimed in claim 8, wherein said memory comprises a recirculating memory.

Claim 16

Dependent Claim 15 words

An apparatus as claimed in claim 8, wherein said combiner comprises an exclusive OR gate.

Claim 17

Dependent Claim 24 words

An apparatus as claimed in claim 8, wherein said memory is configured to store a unique one of a predetermined set of different numbers.

Claim 18

Independent Claim 92 words

An apparatus comprising: 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.

Claim 19

Independent Claim 92 words

An apparatus comprising: 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.

Claim 20

Dependent Claim 24 words

An apparatus as claimed in claim 16, wherein said number generator comprises a linear feedback shift register configured to provide a maximal length sequence.

Claim 21

Dependent Claim 43 words

An apparatus as claimed in claim 16, wherein said second messages are transmitted at a 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.

Claim 22

Dependent Claim 38 words

An apparatus as claimed in claim 16, wherein said second messages comprise code domain multiple access messages encoded using a code chosen from a predetermined list of codes in accordance with a number obtained from said number generator.

Claim 23

Dependent Claim 26 words

An apparatus as claimed in claim 16, wherein said predetermined number is a serial number identifying a particular remote device of said plurality of remote devices.

Claim 24

Independent Claim 162 words

An apparatus comprising: 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.

Claim 25

Independent Claim 162 words

An apparatus comprising: 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.

Claim 26

Independent Claim 145 words

An apparatus comprising: 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.

Claim 27

Independent Claim 145 words

An apparatus comprising: 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.

Claim 28

Dependent Claim 29 words

An apparatus as claimed in claim 22, wherein said number generation means comprises a linear feedback shift register configured to provide a maximal length sequence at said first port.

Claim 29

Dependent Claim 44 words

An apparatus as claimed in claim 22, wherein said second messages are transmitted at a time chosen in response to a number obtained from said number generation means, said time denoting a time interval measured from a time of receipt of said first message.

Claim 30

Dependent Claim 39 words

An apparatus as claimed in claim 22, wherein said second messages comprise code domain multiple access messages encoded using a code chosen from a predetermined list of codes in accordance with a number obtained from said number generation means.

Claim 31

Dependent Claim 26 words

An apparatus as claimed in claim 22, wherein said predetermined number is a serial number identifying a particular remote device of said plurality of remote devices.

Claim 32

Dependent Claim 80 words

An apparatus as claimed in claim 22, wherein: said predetermined number is a serial number identifying a particular remote device of said plurality of remote devices; said number generation means comprises a linear feedback shift register configured to provide a maximal length sequence; and said second messages are transmitted at a time chosen in response to a number obtained from said number generation means, said time denoting a time interval measured from a time of receipt of said first message.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2000-02-25	2000-08-26	2001-02-25	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2004-02-25	2004-08-26	2005-02-25	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2008-02-25	2008-08-26	2009-02-25	$7700.00	Window Closed / Lapsed

Divergent code generator and method

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