Systems and methods employing a plurality of signal amplitudes to identify an object

Claim 2

In a system including an article having a circuit for receiving an interrogation signal and transmitting a circuit signal, the circuit signal being a function of the interrogation signal, and having a nonlinearity at a first circuit signal frequency, the nonlinearity corresponding to an amplitude level of the interrogation signal, a method comprising the steps of: detecting the amplitude level by varying an amplitude used to transmit the interrogation signal to the circuit; detecting a set of other circuit signal frequencies at which the circuit signal has other nonlinearities corresponding to the amplitude level; and generating, responsive to the set of other circuit signal frequencies, an identification signal for the article.

Claim 3

The method of claim 1 wherein the step of detecting the amplitude level includes causing the interrogation signal to have a first interrogation signal frequency, and the step of detecting a set of other circuit signal frequencies includes causing the interrogation signal to have other interrogation signal frequencies.

Claim 4

The method of claim 1 wherein the generating step includes generating a plurality of digits, each digit corresponding to a respective frequency in the set of other circuit signal frequencies.

Claim 5

The method of claim 2 wherein the generating step includes generating a plurality of digits, each digit corresponding to a respective frequency in the set of other circuit signal frequencies.

Claim 6

In a system including a plurality of articles each having a respective circuit for receiving an interrogation signal and transmitting a respective circuit signal, the circuit signal being a function of the interrogation signal, and having a nonlinearity at a first circuit signal frequency, the nonlinearity corresponding to a respective amplitude level of the interrogation signal, a method comprising the steps of: detecting, for each circuit, the respective amplitude level by varying an amplitude used to transmit the interrogation signal to the plurality of articles; detecting, for each circuit, a respective set of other circuit signal frequencies at which the respective circuit signal has other nonlinearities corresponding to the respective amplitude level; and generating, responsive to the previous step, a respective identification signal for each article.

Claim 7

In a system including a plurality of articles each having a respective circuit for receiving an interrogation signal and transmitting a respective circuit signal, the circuit signal being a function of the interrogation signal, and having a nonlinearity at a first circuit signal frequency, the nonlinearity corresponding to a respective amplitude level of the interrogation signal, a method comprising the steps of: detecting, for each circuit, the respective amplitude level by varying an amplitude used to transmit the interrogation signal to the plurality of articles; detecting, for each circuit, a respective set of other circuit signal frequencies at which the respective circuit signal has other nonlinearities corresponding to the respective amplitude level; and generating, responsive to the previous step, a respective identification signal for each article.

Claim 8

The method of claim 5 wherein the step of detecting the respective amplitude level includes causing the interrogation signal to have a first interrogation signal frequency, and the step of detecting a respective set of other circuit signal frequencies includes causing the interrogation signal to have other interrogation signal frequencies.

Claim 9

The method of claim 5 wherein the generating step includes generating a respective plurality of digits for each article, each digit corresponding to a respective frequency in the respective set of other circuit signal frequencies.

Claim 10

The method of claim 6 wherein the generating step includes generating a respective plurality of digits for each article, each digit corresponding to a respective frequency in the respective set of other circuit signal frequencies.

Claim 11

The method of claim 1 wherein the amplitude level is deemed to be a first amplitude level, and the step of detecting a set of other circuit signal frequencies includes receiving an area signal from an area; detecting a nonlinearity in the area signal, at a second amplitude level; and conditionally detecting another nonlinearity of the circuit signal, depending on a function of the first and second amplitude levels.

Claim 12

The method of claim 9 further including determining the function in accordance with a difference between the first and second amplitude levels.

Claim 13

The method of claim 9 further including determining the function by comparing a number to a difference between the first and second amplitude levels.

Claim 14

The method of claim 9 further including determining the function by comparing a number to a difference between the first and second amplitude levels, the number being greater than zero.

Claim 15

The method of claim 1 wherein the step of detecting the amplitude level includes causing the interrogation signal to have a first interrogation signal frequency at a first time, and the step of detecting a set of other circuit signal frequencies includes causing the interrogation signal to have other interrogation signal frequencies at a time different than the first time.

Claim 16

The method of claim 1 wherein the step of detecting the amplitude level is performed before the step of detecting a set of other circuit signal frequencies.

Claim 17

The method of claim 5 wherein the respective amplitude level is deemed to be a first amplitude level, and the step of detecting a respective set of other circuit signal frequencies includes receiving an area signal from an area; detecting a nonlinearity, in the area signal, at a second amplitude level; and conditionally detecting another nonlinearity of the respective circuit signal, depending on a function of the respective first amplitude level and the second amplitude level.

Claim 18

The method of claim 15 further including determining the function in accordance with a difference between the respective first amplitude level and the second amplitude level.

Claim 19

The method of claim 15 further including determining the function by comparing a number to a difference between the respective first amplitude level and the second amplitude level.

Claim 20

The method of claim 15 further including determining the function by comparing a number to a difference between the respective first amplitude level and the second amplitude level, the number being greater than zero.

Claim 21

The method of claim 5 wherein the step of detecting the respective amplitude level includes causing the interrogation signal to have a first interrogation signal frequency at a first time, and the step of detecting a respective set of other circuit signal frequencies includes causing the interrogation signal to have other interrogation signal frequencies at a time different than the first time.

Claim 22

The method of claim 5 wherein the step of detecting the respective amplitude level is performed before the step of detecting a respective set of other circuit signal frequencies.

Claim 23

An identification system for a system including an article having a circuit for receiving an interrogation signal and transmitting a circuit signal, the circuit signal being a function of the interrogation signal, and having a nonlinearity at a first circuit signal frequency, the nonlinearity corresponding to an amplitude level of the interrogation signal, the identification system comprising: a detector that detects the amplitude level by varying an amplitude used to transmit the interrogation signal to the circuit, and that detects a set of other circuit signal frequencies at which the circuit signal has other nonlinearities corresponding to the amplitude level; and a generator that generates responsive to the set of other circuit signal frequencies, an identification signal for the article.

Claim 24

An identification system for a system including an article having a circuit for receiving an interrogation signal and transmitting a circuit signal, the circuit signal being a function of the interrogation signal, and having a nonlinearity at a first circuit signal frequency, the nonlinearity corresponding to an amplitude level of the interrogation signal, the identification system comprising: a detector that detects the amplitude level by varying an amplitude used to transmit the interrogation signal to the circuit, and that detects a set of other circuit signal frequencies at which the circuit signal has other nonlinearities corresponding to the amplitude level; and a generator that generates responsive to the set of other circuit signal frequencies, an identification signal for the article.

Claim 25

The identification system of claim 21 wherein the detector includes circuitry that causes the interrogation signal to have a first interrogation signal frequency, and circuitry that causes the interrogation signal to have other interrogation signal frequencies.

Claim 26

The identification system of claim 21 wherein the detector includes circuitry that causes the interrogation signal to have a first interrogation signal frequency at a first time, and includes circuitry that causes the interrogation signal to have other interrogation signal frequencies at a time different than the first time.

Claim 27

The identification system of claim 23 wherein the generator includes logic that generates a plurality of digits, each digit corresponding to a respective frequency in the set of other circuit signal frequencies.

Claim 28

The identification system of claim 21 wherein the generator includes a logic that generates a plurality of digits, each digit corresponding to a respective frequency in the set of other circuit signal frequencies.

Claim 29

The identification system of claim 21 wherein the detector includes a receiver that receives an area signal from an area, and the detector acts to detect a nonlinearity, in the area signal, at a second amplitude level, and conditionally determine that the circuit signal has another nonlinearity, depending on a function of the first and second amplitude levels.

Claim 30

The identification system of claim 26 further including logic that determines the function in accordance with a difference between the first and second amplitude levels.

Claim 31

The identification system of claim 26 further including logic that determines the function by comparing a number to a difference between the first and second amplitude levels.

Claim 32

The identification system of claim 26 further including logic that determines the function by comparing a number to a difference between the first and second amplitude levels, the number being greater than zero.

Claim 33

The identification system of claim 21 wherein the detector detects the amplitude level before the detector detects the set of other circuit signal frequencies.

Claim 34

An identification system for a system including a plurality of articles each having a respective circuit for receiving an interrogation signal and transmitting a respective circuit signal, the circuit signal being a function of the interrogation signal, and having a nonlinearity at a first circuit signal frequency, the nonlinearity corresponding to a respective amplitude level of the interrogation signal, the identification system comprising: a detector that detects, for each circuit, the respective amplitude level by varying an amplitude used to transmit the interrogation signal to the plurality of articles, and that detects respective sets of other circuit signal frequencies at which the respective circuit signals have other nonlinearities corresponding to the respective amplitude levels; and a generator that generates, responsive to each respective set, a respective identification signal for each article.

Claim 35

An identification system for a system including a plurality of articles each having a respective circuit for receiving an interrogation signal and transmitting a respective circuit signal, the circuit signal being a function of the interrogation signal, and having a nonlinearity at a first circuit signal frequency, the nonlinearity corresponding to a respective amplitude level of the interrogation signal, the identification system comprising: a detector that detects, for each circuit, the respective amplitude level by varying an amplitude used to transmit the interrogation signal to the plurality of articles, and that detects respective sets of other circuit signal frequencies at which the respective circuit signals have other nonlinearities corresponding to the respective amplitude levels; and a generator that generates, responsive to each respective set, a respective identification signal for each article.

Claim 36

The identification system of claim 31 wherein the detector includes circuitry that causes the interrogation signal to have a first interrogation signal frequency, and circuitry that causes the interrogation signal to have other interrogation signal frequencies.

Claim 37

The identification system of claim 31 wherein the detector includes circuitry that causes the interrogation signal to have a first interrogation signal frequency at a first time, and circuitry that causes the interrogation signal to have other interrogation signal frequencies at a time different than the first time.

Claim 38

The identification system of claim 31 wherein the generator includes logic that generates a respective plurality of digits for each article, each digit corresponding to a respective frequency in the respective set of other circuit signal frequencies.

Claim 39

The identification system of claim 31 wherein the generator includes logic that generates a respective plurality of digits for each article, each digit corresponding to a respective frequency in the respective set of other circuit signal frequencies.

Claim 40

The identification system of claim 31 wherein the amplitude level is deemed to be a first amplitude level, and the detector includes a receiver that receives an area signal from an area, and the detector acts to detect a nonlinearity, in the area signal, at a second amplitude level corresponding to a second frequency of the interrogation signal, and conditionally determine that the respective circuit signal has another nonlinearity, depending on a function of the respective first amplitude level and the second amplitude level.

Claim 41

The identification system of claim 36 further including logic that determines the function in accordance with a difference between the respective first amplitude level and the second amplitude level.

Claim 42

The identification system of claim 36 further including logic that determines the function by comparing a number to a difference between the respective first amplitude level and the second amplitude level.

Claim 43

The identification system of claim 36 further including logic that determines the function by comparing a number to a difference between the respective first amplitude level and the second amplitude level, the number being greater than zero.

Claim 44

The identification system of claim 31 wherein the detector detects the respective amplitude level before the detector detects the respective set of other circuit signal frequencies.