Method and apparatus for optical RF amplitude equalization
First Claim
1. A circuit for performing amplitude 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 optical filtering at points in the plane thereby adjusting the amplitude of each distributed freqeuncy component to form a transformed image; and
means for detecting the transformed image and forming an amplitude-equalized electrical output therefrom.
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Accused Products
Abstract
Amplitude equalization of a distorted multifrequency signal is accomplished by acousto-modulating the signal with a coherent light beam and focusing a resultant image on a Fourier plane where the frequency components of the image are spatially distributed. A control array, positioned in the plane, contains adjacent elements having optical filtering properties variable with respect to each other thereby selectively altering the optical amplitude of each image frequency component passing through the elements. The resultant transformed image then undergoes conversion to an electrical signal having its amplitude equalized relative to the distorted input signal.
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Citations
11 Claims
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1. A circuit for performing amplitude 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 optical filtering at points in the plane thereby adjusting the amplitude of each distributed freqeuncy component to form a transformed image; and means for detecting the transformed image and forming an amplitude-equalized electrical output therefrom. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A circuit for performing amplitude 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 amplitude equalized; the local oscillator light beam being produced by means for selectively varying the optical filtering of different sections of the local oscillator light beam thereby effecting selective amplitude control of the local oscillator beam sections.
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8. A method for performing amplitude 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 filtering at points on the plane thereby adjusting the amplitude of each freqeuncy component and forming a transformed image; and detecting the transformed image and forming an amplitude-equalized electrical output therefrom. - View Dependent Claims (9, 10)
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11. A method for performing amplitude 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 amplitude equalized; the local oscillator light beam produced by selectively varying the optical filtering of respective sections of the local oscillator light beam thereby achieving amplitude control of the local oscillator beam sections.
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Specification