System and method for sample detection based on low-frequency spectral components
First Claim
1. A method for detecting a selected material in a sample, comprisingholding the sample while shielding the sample from ambient electrical and magnetic energy;
- introducing noise into the sample to induce stochastic resonance;
storing, for each of one or more preselected materials including the selected material, a data set containing low-frequency spectral components that are of a selected frequency range approximately above DC;
wherein the data set contains low-frequency spectral components that are of a selected frequency approximately below 50 kHz, and characteristic of the selected material;
producing, adjacent to the sample, a time-domain signal having signal components related to low-frequency electromagnetic radiation produced by the selected material in the sample;
converting the produced signal to an amplified signal from which frequency components above a selected frequency are substantially omitted;
retrieving a data set of low-frequency spectral components characteristic of the selected material;
filtering the produced signal to selectively pass low-frequency spectral components corresponding to low-frequency spectral components of the retrieved data set;
cross-correlating the produced signal with the retrieved data set of low-frequency spectral components to produce a frequency-domain signal, wherein the frequency-domain signal has a frequency approximately above DC;
wherein the frequency-domain signal has a frequency approximately below 50 kHz;
determining whether the frequency-domain signal contains one or more low-frequency signal components that are characteristic of the selected material, and diagnostic of a presence or absence of the selected material in the sample; and
displaying an output associated with whether the frequency-domain signal contains one or more low-frequency signal components that are characteristic of the selected material.
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Accused Products
Abstract
Method and apparatus for detecting a selected material in a sample are disclosed. In the method, the sample is placed adjacent a detector coil, for generating an electromagnetic time-domain signal composed of sample source radiation. The signal is first conditioned to convert the signal to an amplified conditioned signal from which frequency components above a selected frequency have been removed, then filtered to selectively pass low-frequency spectral components that are (i) in a frequency range between dc and 50 khz, and (ii) characteristic of the selected material. The filtered signal is cross-correlated with a data set of low-frequency spectral components that are (i) in a frequency range between dc and 50 khz, and (ii) characteristic of a selected material, to produce a frequency-domain spectrum in the frequency range within DC to 50 khz. This spectrum is then used to determine whether the frequency-domain spectrum contains one or more low-frequency signal components that are characteristic of the selected material, and diagnostic of the presence or absence of such material in the sample.
66 Citations
17 Claims
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1. A method for detecting a selected material in a sample, comprising
holding the sample while shielding the sample from ambient electrical and magnetic energy; -
introducing noise into the sample to induce stochastic resonance; storing, for each of one or more preselected materials including the selected material, a data set containing low-frequency spectral components that are of a selected frequency range approximately above DC; wherein the data set contains low-frequency spectral components that are of a selected frequency approximately below 50 kHz, and characteristic of the selected material; producing, adjacent to the sample, a time-domain signal having signal components related to low-frequency electromagnetic radiation produced by the selected material in the sample; converting the produced signal to an amplified signal from which frequency components above a selected frequency are substantially omitted; retrieving a data set of low-frequency spectral components characteristic of the selected material; filtering the produced signal to selectively pass low-frequency spectral components corresponding to low-frequency spectral components of the retrieved data set; cross-correlating the produced signal with the retrieved data set of low-frequency spectral components to produce a frequency-domain signal, wherein the frequency-domain signal has a frequency approximately above DC; wherein the frequency-domain signal has a frequency approximately below 50 kHz; determining whether the frequency-domain signal contains one or more low-frequency signal components that are characteristic of the selected material, and diagnostic of a presence or absence of the selected material in the sample; and displaying an output associated with whether the frequency-domain signal contains one or more low-frequency signal components that are characteristic of the selected material. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An apparatus for detecting a selected material in a sample, comprising:
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means for placing the sample adjacent a detector coil; means for introducing noise into the sample to induce stochastic resonance; means for detecting an electromagnetic time-domain signal produced in the detector coil by the sample; means for processing the time-domain signal to selectively pass low-frequency spectral components that are of a frequency approximately above DC; wherein the means for processing the time-domain signal selectively pass low-frequency spectral components that are of a frequency approximately below 50 kHz, and characteristic of the selected material; means for cross-correlating the time-domain signal with a data set of low-frequency spectral components that are of a frequency approximately above DC, and of a frequency approximately below 50 kHz, and characteristic of a selected material, to produce a frequency-domain signal in the frequency range of approximately DC to 50 kHz; and means for determining whether the frequency-domain signal contains one or more low-frequency signal components that are characteristic of the selected material, and diagnostic of a presence or absence of the selected material in the sample. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A method for detecting a selected material in a sample, comprising:
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holding the sample adjacent a detector coil, and introducing noise into the sample, to thereby generate an electromagnetic time-domain signal composed of sample source radiation via stochastic resonance; processing the electromagnetic time-domain signal to amplify the electromagnetic time-domain signal, and selectively pass low-frequency spectral components that are in a frequency range of approximately DC to 50 kHz, and characteristic of the selected material; cross-correlating the electromagnetic time-domain signal with a data set of low-frequency spectral components that are in a frequency range of approximately DC to 50 kHz, and characteristic of a selected material, to produce a frequency-domain signal in the frequency range of approximately DC to 50 kHz; and
,determining whether the frequency-domain signal contains one or more low-frequency signal components that are characteristic of the selected material, and diagnostic of the presence or absence of such material in the sample. - View Dependent Claims (16, 17)
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Specification