CORRELATION MEASUREMENT APPARATUS
First Claim
1. An analog signal correlation apparatus for determining correlation between an unknown signal and a known signal according to the equation
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Accused Products
Abstract
An analog correlation measurement apparatus provides a relative correlation figure of merit between an unknown and a known signal. The known signal is photographically stored on a film strip having a plurality of contiguous areas of varying image density. An optical system having a light emitting gallium arsenide diode interrogates the film strip synchronously with the tracing or generation of the unknown signal. As a result of the interrogation, an accumulated voltage value is generated that is equivalent to the mathematical process of summation of a plurality of products. This value is used with a similar value derived from an autocorrelation of the known signal to provide a relative correlation number representing the correlation coefficient.
13 Citations
13 Claims
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1. An analog signal correlation apparatus for determining correlation between an unknown signal and a known signal according to the equation
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2. The analog signal correlation apparatus according to claim 1 wherein said scanning means is an electro-optical transducer.
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3. The analog signal correlation apparatus according to claim 1 wherein said radiant energy means is a light emitting diode.
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4. The analog signal correlation apparatus according to claim 1 wherein the strip of variable translucent material is a strip of photographic film.
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5. The analog signal correlation apparatus according to claim 1 wherein said integrator means is an MOS device having two P regions formed in an N substrate with a superimposed insulated gate electrode extending between said P regions and at least one of said P regions being responsive to radiant energy.
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6. The analog signal correlation apparatus according to claim 5 further including switch means electrically connected to said gate electrode and operable to electrically connect said P regions to a source of potential to charge the capacitance between said radiant energy responsive P region and said substrate.
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7. The analog signal correlation apparatus according to claim 1 wherein said scanning means is an electro-magnetic transducer.
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8. An analog signal correlation apparatus for indicating correlation between an unknown signal and a plurality of known signals, said apparatus comprising:
- scanning means for scanning said unknown signal, generating an electrical equivalent of said unknown signal and for generating a synchronizing signal;
radiant energy means responsive to the output of said scanning means for producing a radiant energy output of varying intensity, said intensity varying according to the output of said scanning means;
a plurality of strips of variable transparency material with each of said strips comprising a plurality of in-line adjacent translucent areas representative of one of said plurality of known signal;
synchronizing means responsive to said synchronizing signal from said scanning means for moving said adjacent translucent areas of said plurality of strips past the varying radiant energy output of said radiant energy means to generate a plurality of second varying radiant energy outputs, each second varying radiant energy output representing the product of one of said plurality of known signals and said unknown signal;
integrator means responsive to said plurality of second varying radiant energy outputs for integrating the products of each of said plurality of known signals and said unknown signal and for storing electrical signals representative thereof, said electrical signals being representative of the correlation values of said unknown signal and said plurality of known signals.
- scanning means for scanning said unknown signal, generating an electrical equivalent of said unknown signal and for generating a synchronizing signal;
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9. The analog signal correlation apparatus according to claim 8 wherein said plurality of strips of variable transparency material comprises a plurality of photographic film strips each representing a different known signal.
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10. The analog signal correlation apparatus according to claim 9 wherein said photographic film strips have contiguous areas of varying image densities each area representing a portion of the total signal.
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11. The analog signal correlation apparatus according to claim 10 wherein said radiant energy means is a light emitting semiconductor.
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12. The analog signal correlation apparatus according to claim 11 wherein said integrator means is an MOS device having at least one light responsive region formed in the substrate.
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13. A signature identification system for determining the relative correlation between a standard signature and a new signature and utilizing a credit card having a photographic strip of varying image density thereon, said image density being a representation of the standard signature, said system comprising:
- a guideway along which said credit card is moved, writing means including a pressure responsive stylus and an indexing table for writing the new signature, said indexing table generating a first electrical signal indicating the horizontal position of the stylus with respect to one end of said table and said pressure responsive stylus generating a second electrical signal indicating the pressure applied thereto, first amplifier means responsive to the electrical signal generated by said indexing table for moving said credit card along said guideway in synchronism with the transverse movement of said stylus along said table during the writing of the new signature, a variable light source positioned along and to one side of said guideway for interrogating said photographic strip of said credit card, second amplifier means responsive to said second electrical signal for varying the current applied to said light source to vary the light intensity thereof on said photographic strip as said strip is moved along said guideway, and a light energy responsive circuit responsive to the light emitting from said light source passing through said photographic strip for generating a voltage value as a result of thE electro-optical multiplication of said light intensity and said image density at predetermined intervals.
Specification