Method and apparatus for optical RF phase equalization
First Claim
1. A circuit for performing phase equalization on frequency components of an electrical signal, the circuit comprising:
- means for modulating a coherent light beam with a multifrequency electrical input signal to form an image;
means for forming a Fourier plane and spatially distributing the frequency components of the image on the plane;
means located in the Fourier plane for controlling the optical path length at points in the plane thereby shifting the phase of each distributed frequency component to form a transformed image; and
means for detecting the transformed image and forming a phase-equalized electrical output therefrom.
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Accused Products
Abstract
Phase equalization of a phase-distorted multifrequency signal is accomplished by acousto-optic modulating a coherent light beam with the signal taking the optical Fourier transform with the resultant Fourier plane containing all frequency components spatially distributed. A control array, positioned in the Fourier plane and/or local oscillator, contains adjacent elements having their birefringence variable with respect to each other thereby selectively altering the light path length and/or amplitude of each frequency component passing through the element. The resultant transformed image then undergoes optical down conversion to obtain the electrical signal having its phase equalized relative to the distorted input signal.
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Citations
11 Claims
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1. A circuit for performing phase equalization on frequency components of an electrical signal, the circuit comprising:
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means for modulating a coherent light beam with a multifrequency electrical input signal to form an image; means for forming a Fourier plane and spatially distributing the frequency components of the image on the plane; means located in the Fourier plane for controlling the optical path length at points in the plane thereby shifting the phase of each distributed frequency component to form a transformed image; and means for detecting the transformed image and forming a phase-equalized electrical output therefrom. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A circuit for performing phase equalization on frequency components of an electrical signal, the circuit comprising:
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means for modulating a coherent light beam with a multifrequency electrical input signal to form an image; means for forming a Fourier plane and spatially distributing the frequency components of the image on the plane; means for combining the spatially distributed image with a local oscillator light beam for down converting the image; photodetector means for changing the down converted image to an electrical signal which is phase equalized; the local oscillator light beam being produced by means for selectively varying the light path of different sections of the local oscillator light beam thereby effecting selective phase control of the local oscillator beam sections.
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8. A method for performing phase equalization on frequency components of an electrical signal, the circuit comprising:
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modulating a coherent light beam with a multifrequency electrical input signal to form an image; forming a Fourier plane and spatially distributing the frequency components of the image; controlling the optical path length at points on the plane thereby shifting the phase of each frequency component and forming a transformed image; and detecting the transformed image and forming a phase-equalized electrical output therefrom. - View Dependent Claims (9, 10)
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11. A method for performing phase equalization on frequency components of an electrical signal, the circuit comprising:
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modulating a coherent light beam with a multifrequency electrical input signal to form an image; forming a Fourier plane and spatially distributing the frequency components of the image; combining the spatially distributed image with a local oscillator light beam for down converting the image; and changing the down-converted image to an electrical signal which is phase equalized; the local oscillator light beam produced by selectively varying the optical path of respective sections of the local oscillator light beam thereby achieving phase control of the local oscillator beam sections.
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Specification