Linear swept frequency generator
First Claim
1. A linear swept frequency generator comprising:
- a signal generator operable to generate an output signal having a frequency that sweeps between a first frequency and a second frequency;
a delay element configured to receive the output signal and operable to produce a delayed version of the output signal;
a mixer configured to receive the output signal and the delayed output signal and operable to combine the output signal and the delayed output signal to produce a reference signal indicative of a difference therebetween; and
a feedback path between the mixer and the signal generator, receiving a fixed frequency reference signal and operable to produce a control signal according to the fixed frequency reference signal and the reference signal;
wherein the signal generator controls an aspect of the frequency of the output signal in response to the control signal.
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Accused Products
Abstract
A linear swept frequency generator includes a signal generator that generates an output signal having a frequency that varies between a first frequency and a second frequency. A delay element, such as an optical fiber having a reflector at one end, is configured to receive the output signal and to produce a delayed version of the output signal. This delayed version of the output signal is provided, along with the output signal, to a mixer that combines the signals to produce a reference signal. Finally, a feedback path between the mixer and the signal generator provides the reference signal to the signal generator so that the signal generator controls the frequency of the output signal in response to the reference signal.
92 Citations
31 Claims
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1. A linear swept frequency generator comprising:
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a signal generator operable to generate an output signal having a frequency that sweeps between a first frequency and a second frequency; a delay element configured to receive the output signal and operable to produce a delayed version of the output signal; a mixer configured to receive the output signal and the delayed output signal and operable to combine the output signal and the delayed output signal to produce a reference signal indicative of a difference therebetween; and a feedback path between the mixer and the signal generator, receiving a fixed frequency reference signal and operable to produce a control signal according to the fixed frequency reference signal and the reference signal; wherein the signal generator controls an aspect of the frequency of the output signal in response to the control signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A system for measuring sweep linearity of a swept frequency signal, comprising:
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an optical delay element configured to receive a swept frequency signal having a frequency that varies between a first frequency and a second frequency, and to produce a delayed version of the swept frequency signal; and a mixer configured to receive the swept frequency signal and the delayed version of the swept frequency signal and operable to combine the swept frequency signal and the delayed version of the swept frequency signal to produce a reference signal indicative of a linearity at which the frequency of the swept frequency signal varies from the first frequency to the second frequency. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A sensor querying system comprising:
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an optical fiber; at least one sensor positioned along the optical fiber and configured to reflect light at a level corresponding to a value sensed by the at least one sensor; a signal generator operable to generate a swept frequency signal having a frequency that varies between a first frequency and a second frequency and configured to provide the swept frequency signal to the optical fiber; a mixer configured to receive the swept frequency signal and a signal produced by the optical fiber in response to the swept frequency signal, and operable to combine the swept frequency signal and the signal produced by the optical fiber to produce an output signal; and a processor configured to receive the output signal and operable to produce a measure of the value sensed by the at least one sensor in response thereto. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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22. A method of producing a signal having a frequency that linearly sweeps from a first frequency to a second frequency, comprising:
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generating an output signal having a frequency that varies between the first frequency and the second frequency; generating a delayed version of the output signal; combining the output signal and the delayed output signal to produce a reference signal; producing a control signal by correlating the reference signal and a fixed frequency reference signal; and controlling the frequency of the output signal using the control signal. - View Dependent Claims (23, 24)
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25. A method of measuring sweep linearity of a swept frequency signal, comprising:
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producing a optically delayed version of a swept frequency signal having a frequency that varies between a first frequency and a second frequency; and combining the swept frequency signal and the delayed version of the swept frequency signal to produce a reference signal indicative of the linearity at which the frequency of the swept frequency signal varies from the first frequency to the second frequency. - View Dependent Claims (26, 27)
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28. A method of measuring a value sensed by at least one sensor that is positioned along an optical fiber and configured to reflect light at a level corresponding to the value sensed by the sensor, comprising:
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generating a swept frequency signal having a frequency that varies between a first frequency and a second frequency; providing the swept frequency signal to the optical fiber; combining the swept frequency signal and a signal produced by the optical fiber in response to the swept frequency signal to produce an output signal; and producing a measure of the value sensed by the at least one sensor in response to the output signal. - View Dependent Claims (29, 30, 31)
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Specification