Tunable optical receiver
First Claim
1. A system for determining information on one or more constituents in a medium, the system comprising:
- N light emitters L1 . . . LN, wherein each light emitter Lx is configured to provide an amplitude modulated (AM) light at modulation frequency fx into a flow path of the medium from one side of a containment vessel for the medium, wherein each light emitter Lx uses a different modulation frequency fx, wherein N is an integer greater than 1, and x is an integer greater than or equal to 1 and less than or equal to N, and wherein within the modulation frequencies f1 . . . fN, no two modulation frequencies are harmonically related;
a photodetector configured to receive the AM light from each light emitter after it passes through the flow path of the medium, and convert the AM light to an electrical signal characterized by a summation of frequency components from each modulation frequency fx;
a blocking capacitor configured to remove a DC offset from the electrical signal;
a multiplier configured to generate a mixed output signal by multiplying the electrical signal without DC offset and a matching signal; and
one or more measuring circuits configured to provide information about a concentration of one or more constituents in the medium by processing the mixed output signal to determine log ratios of a pair of amplitudes of fy and fz frequency components in the electrical signal, wherein y and z are integers greater than or equal to 1 and less than or equal to N, and y is not equal to z.
1 Assignment
0 Petitions
Accused Products
Abstract
An embodiment of the disclosure provides a system for determining information on one or more constituents in a medium. The system includes N light emitters L1 . . . LN, wherein each light emitter Lx provides an amplitude modulated (AM) light at modulation frequency fx into a flow path of the medium from one side of a containment vessel for the medium. The system further includes a photodetector, for receiving the AM light from each light emitter after it passes through the flow path of the medium, and converting the AM light to an electrical signal characterized by a summation of frequency components from each modulation frequency fx. The system further includes one or more measuring circuits providing information about a concentration of one or more constituents in the medium determined from log ratios of a pair of amplitudes of fy and fz frequency components in the electrical signal.
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Citations
16 Claims
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1. A system for determining information on one or more constituents in a medium, the system comprising:
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N light emitters L1 . . . LN, wherein each light emitter Lx is configured to provide an amplitude modulated (AM) light at modulation frequency fx into a flow path of the medium from one side of a containment vessel for the medium, wherein each light emitter Lx uses a different modulation frequency fx, wherein N is an integer greater than 1, and x is an integer greater than or equal to 1 and less than or equal to N, and wherein within the modulation frequencies f1 . . . fN, no two modulation frequencies are harmonically related; a photodetector configured to receive the AM light from each light emitter after it passes through the flow path of the medium, and convert the AM light to an electrical signal characterized by a summation of frequency components from each modulation frequency fx; a blocking capacitor configured to remove a DC offset from the electrical signal; a multiplier configured to generate a mixed output signal by multiplying the electrical signal without DC offset and a matching signal; and one or more measuring circuits configured to provide information about a concentration of one or more constituents in the medium by processing the mixed output signal to determine log ratios of a pair of amplitudes of fy and fz frequency components in the electrical signal, wherein y and z are integers greater than or equal to 1 and less than or equal to N, and y is not equal to z. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for determining information on one or more constituents in a medium, the method comprising:
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varying, by a driving circuit, current provided to N light emitters L1 . . . LN in a sinusoidal manner so that each light emitter Lx provides an amplitude modulated (AM) light at modulation frequency fx into a flow path of the medium from one side of a containment vessel for the medium, wherein each light emitter Lx uses a different modulation frequency fx, wherein N is an integer greater than 1, and x is an integer greater than or equal to 1 and less than or equal to N, and wherein within the modulation frequencies f1 . . . fN, no two modulation frequencies are harmonically related; receiving, by a photodetector, the AM light from each light emitter after it passes through the flow path of the medium and converting the AM light to an electrical signal characterized by a summation of frequency components from each modulation frequency fx; removing a DC offset from the electrical signal; generating, by a multiplier, two mixed output signals by multiplying the electrical signal without DC offset and two matching signals; and extracting, by a measuring circuit, log ratios of the amplitudes of fy and fz frequency components in the electrical signal by processing the two mixed output signals to determine information about a concentration of one or more constituents in the medium, wherein y and z are integers greater than or equal to 1 and less than or equal to N, and y is not equal to z. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A non-transient computer readable medium containing program instructions for determining information on one or more constituents in a medium, such that when the instructions are executed by a processor coupled to N light emitters L1 . . . LN and a photodetector, the processor performs the method of:
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varying driving current provided to the N light emitters in a sinusoidal manner so that each light emitter Lx provides an amplitude modulated (AM) light at modulation frequency fx into a flow path of the medium from one side of a containment vessel for the medium, wherein each light emitter Lx uses a different modulation frequency fx, wherein N is an integer greater than 1, and x is an integer greater than or equal to 1 and less than or equal to N, and wherein within the modulation frequencies f1 . . . fN, no two modulation frequencies are harmonically related; receiving an electrical signal without DC offset from a blocking capacitor coupled to the photodetector, wherein the electrical signal without DC offset is generated from an electrical signal representing the AM light from each light emitter received at the photodetector after the AM light passes through the flow path of the medium; providing two matching signals with frequencies fy and fz to a multiplier, so that the multiplier generates two mixed output signals by multiplying the electrical signal without DC offset and the two matching signals; and extracting log ratios of amplitudes of fy and fz frequency components in the electrical signal by processing the two mixed output signals to determine information about a concentration of one or more constituents in the medium, wherein y and z are integers greater than or equal to 1 and less than or equal to N, and y is not equal to z; wherein the electrical signal is characterized by a summation of frequency components from each modulation frequency fx. - View Dependent Claims (14)
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15. A system for determining information on one or more constituents in a medium, the system comprising:
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N light emitters L1 . . . LN, wherein each light emitter Lx is configured to provide an amplitude modulated (AM) light at modulation frequency fx into a flow path of the medium from one side of a containment vessel for the medium, wherein each light emitter Lx uses a different modulation frequency fx, and wherein N is an integer greater than 1, and x is an integer greater than or equal to 1 and less than or equal to N; a photodetector configured to receive the AM light from each light emitter after it passes through the flow path of the medium, and convert the AM light to an electrical signal characterized by a summation of frequency components from each modulation frequency fx; and one or more measuring circuits configured to; provide information about a concentration of one or more constituents in the medium determined from log ratios of a pair of amplitudes of fy and fz frequency components in the electrical signal, wherein y and z are integers greater than or equal to 1 and less than or equal to N, and y is not equal to z, provide a phase difference between a phase of an fx frequency component of the electrical signal and a phase of a current driving the Lx emitter, and determine a change in the phase difference, wherein the change in the phase difference provides information about a change in the composition of the medium.
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16. A method for determining information on one or more constituents in a medium, the method comprising:
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varying, by a driving circuit, current provided to N light emitters L1 . . . LN in a sinusoidal manner so that each light emitter Lx provides an amplitude modulated (AM) light at modulation frequency fx into a flow path of the medium from one side of a containment vessel for the medium, wherein each light emitter Lx uses a different modulation frequency fx, and wherein N is an integer greater than 1, and x is an integer greater than or equal to 1 and less than or equal to N; receiving, by a photodetector, the AM light from each light emitter after it passes through the flow path of the medium and converting the AM light to an electrical signal characterized by a summation of frequency components from each modulation frequency fx; extracting, by a measuring circuit, log ratios of the amplitudes of fy and fz frequency components in the electrical signal to determine information about a concentration of one or more constituents in the medium, wherein y and z are integers greater than or equal to 1 and less than or equal to N, and y is not equal to z; determining, by the measuring circuit, a phase difference between a phase of an fx frequency component of the electrical signal and a phase of a current driving the Lx emitter; and determining, by the measuring circuit, a change in the phase difference, wherein the change in the phase difference provides information about a change in the composition of the medium.
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Specification