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US 6,580,064 B1Granted
Background rejection circuit
AssigneeThe United States of America as represented by the Secretary of the Navy
InventorsMarkam F. Stenger, Alan D. Woodson
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Abstract
A background rejection circuit uses the harmonic content of an angularly narrow target to produce a signal. The signal is used to modulate an externally derived audio signal to produce a target indication signal free of background noise.
Claims10
A photo-electric processing system comprising:
- an acceptance optical system for passing radiation therethrough;
- a reticle positioned with respect to said optical system to chop radiation passed thereby;
- an electro-optical transducer positioned with respect to said reticle to produce an electrical analog of said chopped radiation;
- a processing circuit connected to said electro-optical transducer for enhancing a signal from a source of radiation of small angular dimensions and including,
- a first filter having an input connected to said electro-optical transducer and having an output,
- a first source of audio frequency electrical energy,
- a summing circuit having an input connected to the output of said first filter and an input connected to said first source of audio frequency electrical energy and having an output,
- a second filter having an input connected to the output of said summing circuit and having an output,
- a second source of audio frequency electrical energy, and
- an audio circuit connected to the output of said second filter and said second source of audio frequency energy.
7 more elements
Dependencies are inferred from the claim text.