Microwave oscillator with noise degeneration feedback circuit
First Claim
1. A signal source comprising:
- (a) an oscillator having an output and a control port; and
(b) a feedback circuit disposed between the output and the control port of the oscillator, the feedback circuit comprising;
(i) a modulated laser, having an input and an output, the input coupled to the output of the oscillator;
(ii) a fiber-optic cable having a first end and a second end, the first end connected to the output of the modulated laser; and
(iii) a photo detector having an input and an output, the input connected to the second end of the fiber-optic cable.
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Accused Products
Abstract
A microwave oscillator is shown to include an oscillator having an output and a control port and a feedback circuit disposed between the output and the control port of the oscillator. The feedback circuit includes a modulated laser, having an input and an output, the input responsive to a portion of a signal from the output of the oscillator and a photo detector having an input and an output, the input of the photo detector responsive to a signal from the output of the modulated laser delayed by a predetermined amount of time. The feedback circuit further includes a detector having a first and a second input and an output, the first input of the detector responsive to a signal from the output of the photo detector, the second input responsive to a portion of the signal from the output of the oscillator shifted in phase to be in phase quadrature with the signal at the first input of the detector and the output of the detector coupled to the control port of the oscillator. With such an arrangement, a microwave oscillator having improved FM noise performance than known microwave oscillators is provided.
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Citations
16 Claims
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1. A signal source comprising:
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(a) an oscillator having an output and a control port; and (b) a feedback circuit disposed between the output and the control port of the oscillator, the feedback circuit comprising; (i) a modulated laser, having an input and an output, the input coupled to the output of the oscillator; (ii) a fiber-optic cable having a first end and a second end, the first end connected to the output of the modulated laser; and (iii) a photo detector having an input and an output, the input connected to the second end of the fiber-optic cable. - View Dependent Claims (2, 3, 4)
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5. A microwave oscillator comprising:
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(a) means, responsive to a control signal, for providing an output signal with an output frequency; and (b) means, responsive to a portion of the output signal, for providing the control signal to reduce variation of the frequency of the output signal, wherein the control signal providing means comprises; (i) a modulated laser, having an input and an output, the input coupled to the output signal; (ii) a fiber-optic cable having a first end and a second end, the first end connected to the output of the modulated laser; and (iii) a photo detector having an input and an output, the input connected to the second end of the fiber-optic cable. - View Dependent Claims (6, 7, 8)
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9. A microwave frequency signal source comprising:
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(a) means, responsive to a control signal, for providing a microwave frequency output signal; (b) means, responsive to a portion of the microwave frequency output signal, for providing a modulated optical signal, the modulated optical signal time delayed by a predetermined amount of time; (c) means, responsive to the time delayed modulated optical signal, for providing a microwave feedback signal; (d) means, responsive to the microwave feedback signal and a portion of the microwave frequency output signal, for providing the control signal for the microwave frequency output signal providing means. - View Dependent Claims (10, 11, 12)
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13. A signal source comprising:
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(a) an oscillator having an output and a control port; and (b) a feedback circuit disposed between the output and the control port of the oscillator, the feedback circuit comprising; (i) a first modulated laser, having an input and an output, the input coupled to the output of the oscillator; (ii) a second modulated laser, having an input and an output, the input coupled to the output of the oscillator; (iii) a first photo detector having an input and an output; (iv) a second photo detector having an input and an output; (v) a first fiber-optic cable having a first end and a second end, the first end connected to the output of the first modulated laser and the second end connected to the input of the first photo detector; and (vi) a second fiber-optic cable having a first end and a second end, the first end connected to the output of the second modulated laser and the second end connected to the input of the second photo detector. - View Dependent Claims (14, 15, 16)
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Specification