Patent US4579421A successfully refreshed from Google Patents.
US4579421A
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Optical adaptive filter
Assignee: National Security Agency
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Filing: 1983-10-05
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Granted: 1986-04-01
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Expires: 2003-10-05
Abstract
Abstract An electrooptic apparatus is disclosed for linear predictive adaptive filtering. The apparatus combines the desirable filtering effects of a correlation cancellation loop method of linear prediction with the parallelism and large bandwidth capabilities of optical processing.
Inventors
- 👤 Douglas E. Brown
- 👤 Joanne F. Rhodes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 08:38
CPC Classifications
G; G06; G06E; G06E3/00; G06E3/001; G06E3/005
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
202 words
An electrooptic signal processing apparatus, comprising: a source of an electrical information signal; a first source of coherent light; first modulating means for intensity modulating the output of said first light source in response to an electrical signal to produce a first intermediate optical signal; second modulating means for modulating said first intermediate optical signal in response to delayed samples of said information signal to produce a second intermediate optical signal; means for integrating said second intermediate optical signal; a second source of coherent light; third modulating means for modulating the output of said second light source in accordance with the integrated values of said second intermediate optical signal to produce a third intermediate optical signal proportional to the integrated signals; fourth modulating means for modulating said third intermediate optical signal in response to delayed samples of said information signal to provide a fourth intermediate optical signal comprising a plurality of weighted samples; means for converting said fourth intermediate optical signal into an electrical output representative of the sum of said weighted samples; means for producing an electrical signal representing the difference of said electrical output and said information signal; and means for providing said difference signal to said first modulating means.
Claim 2
Dependent Claim
202 words
An electrooptic signal processing apparatus, comprising: a source of an electrical information signal; a first source of coherent light; first modulating means for intensity modulating the output of said first light source in response to an electrical signal to produce a first intermediate optical signal; second modulating means for modulating said first intermediate optical signal in response to delayed samples of said information signal to produce a second intermediate optical signal; means for integrating said second intermediate optical signal; a second source of coherent light; third modulating means for modulating the output of said second light source in accordance with the integrated values of said second intermediate optical signal to produce a third intermediate optical signal proportional to the integrated signals; fourth modulating means for modulating said third intermediate optical signal in response to delayed samples of said information signal to provide a fourth intermediate optical signal comprising a plurality of weighted samples; means for converting said fourth intermediate optical signal into an electrical output representative of the sum of said weighted samples; means for producing an electrical signal representing the difference of said electrical output and said information signal; and means for providing said difference signal to said first modulating means.
Claim 3
Dependent Claim
14 words
The apparatus of claim 1 wherein said first and second light sources are lasers.
Claim 4
Dependent Claim
14 words
The apparatus of claim 2 wherein said first modulating means is an electrooptic modulator.
Claim 5
Dependent Claim
14 words
The apparatus of claim 3 wherein said second modulating means is a Bragg cell.
Claim 6
Dependent Claim
19 words
The apparatus of claim 4 wherein said integrating means is the photodetector side of a liquid crystal light valve.
Claim 7
Dependent Claim
21 words
The apparatus of claim 5 wherein the third modulating means is the liquid crystal side of a liquid crystal light valve.
Claim 8
Dependent Claim
14 words
The apparatus of claim 6 wherein said fourth modulating means is a Bragg cell.
Claim 9
Dependent Claim
13 words
The apparatus of claim 7 wherein said converting means is a photomultiplier tube.
Claim 10
Dependent Claim
14 words
The apparatus of claim 8 wherein said difference producing means is a differential amplifier.
References Cited (Backward Citations)
US3592527A
Cited
US3744879A
Cited
US4368386A
Cited
US4225938A
Cited
US4310894A
Cited
US4389092A
Cited
US4440472A
Cited
US4468093A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-03-31 | 1989-09-30 | 1990-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-03-31 | 1993-09-30 | 1994-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-03-31 | 1997-09-30 | 1998-04-01 | $7700.00 | Window Closed / Lapsed |