Frequency hopping spread spectrum passive acoustic wave identification device
First Claim
1. A system for interrogating a passive acoustic transponder, producing a transponder signal having characteristic set of signal perturbations in response to an interrogation signal, comprising:
- (a) a signal generator, producing an interrogation signal having a plurality of differing frequencies;
(b) a receiver, for receiving the transponder signal;
(c) a mixer, for mixing said transponder signal with a signal corresponding to said interrogation signal, to produce a mixed output;
(d) an integrator, integrating said mixed output to define an integrated phase-amplitude response of the received transponder signal for each of said differing frequencies; and
(e) an analyzer, receiving a plurality of integrated phase-amplitude responses corresponding to said plurality of differing frequencies, for determining the characteristic set of signal perturbations of the passive acoustic transponder.
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Abstract
A system and method for interrogating a passive acoustic transponder, producing a transponder signal having characteristic set of signal perturbations in response to an interrogation signal, comprising a signal generator, producing an interrogation signal having a plurality of differing frequencies; a receiver, for receiving the transponder signal; a mixer, for mixing the transponder signal with a signal corresponding to the interrogation signal, to produce a mixed output; an integrator, integrating the mixed output to define an integrated phase-amplitude response of the received transponder signal; and an analyzer, receiving a plurality of integrated phase-amplitude responses corresponding to the plurality of differing frequencies, for determining the characteristic set of signal perturbations of the passive acoustic transponder.
96 Citations
42 Claims
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1. A system for interrogating a passive acoustic transponder, producing a transponder signal having characteristic set of signal perturbations in response to an interrogation signal, comprising:
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(a) a signal generator, producing an interrogation signal having a plurality of differing frequencies;
(b) a receiver, for receiving the transponder signal;
(c) a mixer, for mixing said transponder signal with a signal corresponding to said interrogation signal, to produce a mixed output;
(d) an integrator, integrating said mixed output to define an integrated phase-amplitude response of the received transponder signal for each of said differing frequencies; and
(e) an analyzer, receiving a plurality of integrated phase-amplitude responses corresponding to said plurality of differing frequencies, for determining the characteristic set of signal perturbations of the passive acoustic transponder. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A method for interrogating a passive acoustic transponder, producing a transponder signal having characteristic set of signal perturbations in response to an interrogation signal, comprising:
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(a) producing an interrogation signal having a plurality of differing frequencies;
(b) receiving the transponder signal from the passive acoustic transponder;
(c) mixing the transponder signal with a signal corresponding to the interrogation signal, to produce a mixed output;
(d) integrating the mixed output to define an integrated phase-amplitude response of the received transponder signal; and
(e) analyzing a plurality of integrated phase-amplitude responses corresponding to the plurality of differing frequencies, to determine the characteristic set of signal perturbations of the passive acoustic transponder.
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30. A method for identifying a passive acoustic transponder, having a set of characteristic signal perturbations selected from a signal perturbation space having a plurality of degrees of freedom, and producing a perturbed signal in response to an interrogation, comprising the steps of:
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(a) interrogating the passive acoustic transponder with a frequency hopping spread spectrum signal, having a psueodorandom sequence of a plurality of different frequencies, and a stationary frequency dwell period;
(b) receiving and demodulating the perturbed signal based on a representation of the frequency hopping spread spectrum signal;
(c) determining an average phase-amplitude response of the demodulated perturbed signal during a plurality of dwell periods; and
(d) analyzing the average phase-amplitude response from the plurality of dwell periods to determine the values of the plurality of degrees of freedom. - View Dependent Claims (31, 32, 33)
(e) providing a plurality of passive acoustic transponders;
(f) storing in a database an association of an identification of each passive acoustic transponder with values identifying the values of the plurality of degrees of freedom; and
(g) based on the determined values of the plurality of degrees of freedom, retrieving an identification of a passive acoustic transponder from the database.
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32. The method according to claim 30, further comprising the steps of providing a plurality of passive acoustic transponders, each physically associated with an object;
- storing in a database an association of each passive acoustic transponder with the object, including the values identifying the values of the plurality of degrees of freedom; and
based on the determined values of the plurality of degrees of freedom, retrieving an identification of an object associated with the transponder from the database.
- storing in a database an association of each passive acoustic transponder with the object, including the values identifying the values of the plurality of degrees of freedom; and
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33. The method according to claim 30, wherein said frequency hopping spread spectrum signal further comprises a quiet period during which no signal is emitted.
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34. A system for determining characteristics of an acoustic wave transponder, producing a transponder signal having characteristic set of signal perturbations in response to an interrogation signal and an internal reference, comprising:
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(a) an interrogation signal generator, producing a non-stationary interrogation signal hopping to a plurality of differing frequencies;
(b) a receiver, for receiving the transponder signal;
(c) a demodulator, for demodulating a signal dependent on characteristics of the transponder from said interrogation signal, to produce a demodulated output;
(d) a phase-amplitude detector, detecting a phase-amplitude relationship of said demodulated output with respect to the reference; and
(e) an analyzer, sequentially receiving a plurality of detected phase-amplitude relationships corresponding to said plurality of differing frequencies, for determining the characteristic set of signal perturbations of the acoustic wave transponder. - View Dependent Claims (35, 36)
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37. A method for analyzing a frequency hopping spread spectrum interrogated passive acoustic transponder comprising the steps of:
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receiving a transponder signal;
demodulating the transponder signal with a representation of the interrogation signal;
integrating the demodulated transponder signal from a frequency hop with an effective integration time constant smaller than a duration of the respective frequency hop;
determining a relative phase-amplitude shift of the demodulated signal due to interrogation signal perturbations within the transponder, based on the integrated demodulated transponder signal, over a plurality of frequency hops; and
analyzing the determined phase-amplitude shifts to determine a set of component delays within the transponder.
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38. A method for analyzing a frequency hopping spread spectrum interrogated passive acoustic transponder comprising the steps of:
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exciting a transponder with a spread spectrum interrogation signal in a plurality of differing excitation states;
receiving modified signals from the transponder under the plurality of differing excitation states;
demodulating the received signals;
filtering the demodulated received signals with a wide bandwidth filter;
determining a characteristic perturbation of the demodulated received signals for each differing excitation state; and
analyzing the determined characteristic perturbations to determine a set of component perturbation elements within the transponder.
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39. A method for interrogating a passive acoustic transponder with a non-narrow band frequency interrogation signal having a plurality of differing excitation states, comprising the steps of:
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receiving modified signals from the transponder under the plurality of differing excitation states;
demodulating the received signals;
filtering the demodulated received signals with a wide bandwidth filter, having a time constant which is small with respect to the period between transitions of differing excitation states;
determining a characteristic perturbation of the demodulated received signals for each differing excitation state; and
analyzing the determined characteristic perturbations to determine a set of component perturbation elements within the transponder.
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40. A passive radio frequency transponder method for reading information encoded into a passive device, having a maximum time constant, as a set of phase-amplitude variations of signals having respective variation time constants shorter than said maximum time constant, comprising the steps of:
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exciting the passive device with a set of signals having differing frequency components;
receiving a modified set of signals from the passive device with phase-amplitude variations; and
filtering the received signals with a filter having a time constant comparable in magnitude to the maximum time constant of the passive device.
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41. A passive acoustic transponder interrogation system, comprising:
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a transponder, producing a transponder signal having characteristic set of signal perturbations in response to an interrogation signal;
a signal generator, producing an interrogation signal having a plurality of differing frequencies;
a receiver, for receiving the transponder signal;
a mixer, for mixing the transponder signal with a signal corresponding to the interrogation signal, to produce a mixed output;
an integrator, integrating the mixed output to define an integrated phase-amplitude response of the received transponder signal; and
an analyzer, receiving a plurality of integrated phase-amplitude responses corresponding to the plurality of differing frequencies, for determining the characteristic set of signal perturbations of the passive acoustic transponder.
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42. A method for identifying a passive acoustic transponder or an object associated therewith, comprising:
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placing a passive acoustic transponder in proximity to the object, the transponder having a set of characteristic signal perturbations selected from a signal perturbation space having a plurality of degrees of freedom, and producing a perturbed signal in response to an interrogation;
interrogating the passive acoustic transponder with a pseudorandom order, frequency hopping spread spectrum signal, having a sequence of a plurality of different frequencies, and a dwell period;
receiving and demodulating the perturbed signal based on a representation of the pseudorandom order, frequency hopping spread spectrum signal;
determining an average phase-amplitude response of the demodulated perturbed signal during a plurality of dwell periods; and
analyzing the average phase-amplitude response from the plurality of dwell periods to determine the values of the plurality of degrees of freedom.
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Specification