Method and apparatus for measuring low power signals
First Claim
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1. An apparatus for use in measuring low power signals, the apparatus comprising:
- an integrator, wherein the integrator receives an original low power signal from a signal source and integrates the signal over multiple integration periods;
an analog-to-digital converter having an analog input coupled to an output of the integrator, wherein the converter digitally samples the integrator output more than two times during each integration period to obtain multiple digital samples; and
a processor coupled to a digital output of the analog-to-digital converter, wherein the processor determines the original low power signal using the multiple digital samples.
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Abstract
A method and apparatus for measuring very low light signals including integrating a signal from a photo diode, avalanche photo diode, photomultiplier tube or the like, digitally sampling the integrator output more than two times during each integration period, fitting a curve to the multiple digitized readings to calculate the integration slope for each integration period and determining the original signal from the calculated integration slope.
277 Citations
31 Claims
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1. An apparatus for use in measuring low power signals, the apparatus comprising:
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an integrator, wherein the integrator receives an original low power signal from a signal source and integrates the signal over multiple integration periods; an analog-to-digital converter having an analog input coupled to an output of the integrator, wherein the converter digitally samples the integrator output more than two times during each integration period to obtain multiple digital samples; and a processor coupled to a digital output of the analog-to-digital converter, wherein the processor determines the original low power signal using the multiple digital samples. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An apparatus for use in measuring low power light-based signals in a detection region in a first one of at least two intersecting microchannels, the apparatus comprising:
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a photo diode located proximal the detection region which detects a low power light-based signal in the detection region and outputs a photo diode signal; an integrator having an input coupled to an output of the photo diode, wherein the integrator receives and integrates the photo diode signal over multiple integration periods to produce an integrator output signal; a low pass filter having an input coupled to an output of the integrator, wherein the low pass filter operates to filter out frequencies above a selected level in the integrator output signal; an analog-to-digital converter having an analog input coupled to an output of the low pass filter, wherein the converter digitally samples the filtered integrator output signal more than two times during each integration period to obtain multiple digital samples; and a processor coupled to a digital output of the analog-to-digital converter, wherein the processor calculates the integration slope for each integration period using the multiple digital samples, and wherein the processor determines the original low power signal from the calculated integration slopes.
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14. A method of measuring low power signals, comprising the steps of:
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receiving an original signal from a signal source; integrating over multiple integration periods the original signal with an integrator to produce an integrator output signal; digitally sampling the integrator output signal more than two times during each integration period of the integrator output signal with an analog-to-digital converter coupled to the integrator to obtain multiple digital samples; and determining the original signal from the multiple digital samples. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A method of measuring low power light-based signals in a detection region in a first one of at least two intersecting microchannels, the method comprising the steps of:
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locating a photo diode proximal the detection region, wherein the photo diode detects an original low power light-based signal in the detection region and outputs a photo diode signal; integrating the photo diode signal over multiple integration periods to produce an integrator output signal using an integrator having an input coupled to an output of the photo diode; filtering out frequencies above a selected level in the integrator output signal using a low pass filter having an input coupled to an output of the integrator; digitally sampling the filtered integrator output signal more than two times during each integration period with an analog-to-digital converter having an analog input coupled to an output of the low pass filter to obtain multiple digital samples; calculating the integration slope for each integration period using the multiple digital samples; and determining the original low power signal from the calculated integration slopes.
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25. A system for measuring low power signals, the system comprising:
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means for detecting an original low power signal; means for integrating the original low power signal over multiple integration intervals to produce an integration output signal; digital sampling means for digitally sampling the integration output signal more than two times during each integration interval to obtain multiple digital samples; and a processor coupled to the digital sampling means, the processor including; means for calculating the integration slope for each integration interval using the multiple digital samples; and means for determining the original low power signal from the calculated integration slopes. - View Dependent Claims (26, 27, 28, 29, 30, 31)
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Specification