US3745353A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Bragg angle collinear heterodyning filter
Assignee: United States Department of the Navy
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Filing: 1971-10-26
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Granted: 1973-07-10
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Expires: 1991-10-26
Abstract
Abstract A Bragg angle matched filter wherein the light rays reflected by the delay cell are combined with the modulated rays which rebound from the wave plate and travel back through the delay cell. The combined rays are converged by a lens onto an aperture. A photodetector beyond the aperture yields an output proportional to the intensity of the converged wave. Planar waves entering the lens give a maximum output from the photodetector and, therefore, indicate a correlation peak.
Inventors
- 👤 J Jernigan
- 👤 Neill T O
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 14:09
CPC Classifications
G; G02; G02F; G02F2/00; G02F2/002
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
93 words
A matched filter system for recognizing a coded pulse of a given character, comprising: a source of monochromatic spatially coherent light; means for modulating saId light in response to a first modulating signal, including an ultrasonic delay cell positioned so that said light impinges on the cell at the Bragg angle; a wave plate to intercept the modulated wave; means for combining the monochromatic spatially coherent light inherently reflected by the surface on which said light impinges with the intercepted, modulated wave; and means for focusing the combined light waves onto a photodetector.
Claim 2
Dependent Claim
93 words
A matched filter system for recognizing a coded pulse of a given character, comprising: a source of monochromatic spatially coherent light; means for modulating saId light in response to a first modulating signal, including an ultrasonic delay cell positioned so that said light impinges on the cell at the Bragg angle; a wave plate to intercept the modulated wave; means for combining the monochromatic spatially coherent light inherently reflected by the surface on which said light impinges with the intercepted, modulated wave; and means for focusing the combined light waves onto a photodetector.
Claim 3
Dependent Claim
24 words
The matched filter system of claim 1 wherein said systems further comprises; means for modulating said light in response to a second modulating signal.
Claim 4
Dependent Claim
36 words
The matched filter system of claim 2 wherein; said second modulating signal is applied to said ultrasonic delay cell, and said first modulating signal includes the output of said photodetector responsive to said second modulating signal.
Claim 5
Dependent Claim
70 words
The matched filter system of claim 3 wherein; said second modulating signal is coupled to one end of said cell and said first modulating signal is coupled to the other end of said cell, such that ultrasonic waves in response to said second signal propagate substantially longitudinally in said cell from said one end and ultrasonic waves in response to said first signal propagate substantially longitudinally from said other end.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-09 | 1977-01-08 | 1977-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-09 | 1981-01-08 | 1981-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-09 | 1985-01-08 | 1985-07-10 | $7700.00 | Window Closed / Lapsed |