US4566760A
Expired / Lapsed
US
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Multi-product acousto-optic time integrating correlator
Assignee: United States Department of the Army
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Filing: 1984-04-12
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Granted: 1986-01-28
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Expires: 2004-04-12
Abstract
Abstract A device for processing signals to obtain a multi-product, time integrated, correlated output signal. A laser light beam is expanded and shaped into a sheet beam which is directed across the surface of an acousto-optic medium. Four acoustic transducers are disposed on the acousto-optic medium, two at each end of the medium. Each acoustic transducer is supplied with a signal to be propagated on the surface of the acousto-optic medium. The first two signals diffract the sheet beam to produce a first, product diffracted beam of light containing the product of the first two signals. The second two signals diffract the sheet beam to produce a second product diffracted beam of light containing the product of the second two signals. The two product diffracted beams are rotated so that they are orthogonal to each other, and then combined. A time integrating photodetecting means is disposed in the path of the combined beam for generating a multi-product, time integrated, correlated output signal.
Inventors
- 👤 Irwin J. Abramovitz
- 👤 Norman J. Berg
- 👤 Michael W. Casseday
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 16:08
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/06; G01S13/08; G01S13/10; G01S13/26; G01S13/28; G02; G02F; G02F1/00; G02F1/01; G02F1/11; G06; G06E; G06E3/00; G06E3/001; G06E3/005
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
397 words
A device for processing signals to obtain a multi-product, time integrated, correlated output signal, comprising: (a) means for producing a laser light beam; (b) means for expanding said laser light beam into a first sheet beam; (c) an acousto-optic medium having an axis and a planar surface extending between opposite first and second ends which is disposed in the path of said sheet beam such that the sheet beam traverses the medium between the medium ends along and parallel to the medium; (d) a first acoustic transducer, disposed at the first end of the acousto-optic medium; (e) a second acoustic transducer, disposed at the second end of the acousto-optic medium; (f) a third acoustic transducer, disposed at the first end of the acousto-optic medium; (g) a fourth acoustic transducer, disposed at the second end of the acousto-optic medium; (h) a first signal, supplied to said first acoustic transducer, for propagating said first signal on the surface of said acousto-optic medium in the direction of the second end of the acousto-optic medium; (i) a second signal, supplied to said second acoustic transducer, for propagating said second signal on the surface of said acousto-optic medium in the direction of the first end of the acousto-optic medium; (j) a third signal, supplied to said third acoustic transducer, for propagating said third signal on the surface of said acousto-optic medium in the direction of the first end of the acousto-optic medium; (k) a fourth signal, supplied to said fourth acoustic transducer, for propagating said fourth signal on the surface of said acousto-optic medium in the direction of the first end of the acousto-optic medium; (l) wherein said first and second signals diffract said sheet beam to produce a first, product diffracted beam of light, said first product diffracted beam containing the product of said first signal with said second signal; (m) wherein said third and fourth signals diffract said sheet beam to produce a second, product diffracted beam of light, said second product diffracted beam containing the product of said third signal with said second signal; (n) means for rotating said first product diffracted beam and said second product diffracted beam so that they are orthogonal to each other; (o) means to combine said orthogonal, product diffracted beams; and (p) time integrating photodetecting means disposed in the path of the combined beam for generating a multi-product, time integrated, correlated output signal.
Claim 2
Independent Claim
397 words
A device for processing signals to obtain a multi-product, time integrated, correlated output signal, comprising: (a) means for producing a laser light beam; (b) means for expanding said laser light beam into a first sheet beam; (c) an acousto-optic medium having an axis and a planar surface extending between opposite first and second ends which is disposed in the path of said sheet beam such that the sheet beam traverses the medium between the medium ends along and parallel to the medium; (d) a first acoustic transducer, disposed at the first end of the acousto-optic medium; (e) a second acoustic transducer, disposed at the second end of the acousto-optic medium; (f) a third acoustic transducer, disposed at the first end of the acousto-optic medium; (g) a fourth acoustic transducer, disposed at the second end of the acousto-optic medium; (h) a first signal, supplied to said first acoustic transducer, for propagating said first signal on the surface of said acousto-optic medium in the direction of the second end of the acousto-optic medium; (i) a second signal, supplied to said second acoustic transducer, for propagating said second signal on the surface of said acousto-optic medium in the direction of the first end of the acousto-optic medium; (j) a third signal, supplied to said third acoustic transducer, for propagating said third signal on the surface of said acousto-optic medium in the direction of the first end of the acousto-optic medium; (k) a fourth signal, supplied to said fourth acoustic transducer, for propagating said fourth signal on the surface of said acousto-optic medium in the direction of the first end of the acousto-optic medium; (l) wherein said first and second signals diffract said sheet beam to produce a first, product diffracted beam of light, said first product diffracted beam containing the product of said first signal with said second signal; (m) wherein said third and fourth signals diffract said sheet beam to produce a second, product diffracted beam of light, said second product diffracted beam containing the product of said third signal with said second signal; (n) means for rotating said first product diffracted beam and said second product diffracted beam so that they are orthogonal to each other; (o) means to combine said orthogonal, product diffracted beams; and (p) time integrating photodetecting means disposed in the path of the combined beam for generating a multi-product, time integrated, correlated output signal.
Claim 3
Dependent Claim
29 words
The device of claim 1, wherein only two of said signals contain information to be processed; whereby the photodetecting means generates a two product, time integrated, correlated output signal.
Claim 4
Dependent Claim
29 words
The device of claim 1, wherein only three of said signals contain information to be processed; whereby the photodetecting means generates a three product, time integrated, correlated output signal.
Claim 5
Dependent Claim
28 words
The device of claim 1, wherein each of said signals contain information to be processed; whereby the photodetecting means generates a four product, time integrated, correlated output signal.
Claim 6
Dependent Claim
184 words
The device of claim 1, wherein: (a) said axis defines the z-axis, the axis normal to said surface defines the y-axis, and the axis normal to both the z-axis and the x-axis defines the x-axis; (b) said first acoustic transducer is disposed at an angle relative to the x-axis of the acousto-optic medium which is equal to +2θ B , where θ B is the Bragg angle for the acousto-optic medium; (c) said second acoustic transducer is disposed at an angle relative to the x-axis of the acousto-optic medium which is equal to +2θ B , where θ B is the Bragg angle for the acousto-optic medium; (d) said third acoustic transducer is disposed at an angle relative to the x-axis of the acousto-optic medium which is equal to -2θ B , where θ B is the Bragg angle for the acousto-optic medium; and (e) said fourth acoustic transducer is disposed at an angle relative to the x-axis of the acousto-optic medium which is equal to -2θ B , where θ B is the Bragg angle for the fourth signal in the acousto-optic medium.
Claim 7
Dependent Claim
16 words
The device of claim 1, wherein the time integrating photodetecting means comprises a photodiode area array.
Claim 8
Dependent Claim
16 words
The device of claim 1 wherein the time integrating photodetecting means comprises a vidicon tube camera.
Claim 9
Dependent Claim
20 words
The device of claim 1, wherein the acousto-optic medium comprises a surface acoustic wave device built on Y-Z lithium niobate.
Claim 10
Dependent Claim
43 words
The device of claim 1, wherein the means for expanding said laser beam into a sheet beam comprises: (a) a beam expander disposed in the path of said laser beam; and (b) a lens for forming the expanded beam into a sheet beam.
Claim 11
Dependent Claim
32 words
The device of claim 1, further comprising means for filtering undesired diffractions produced by the interaction of said sheet beam with said acousto-optic medium and said first, second, third, and fourth signals.
Claim 12
Dependent Claim
127 words
The device of claim 10, wherein said means for filtering comprises: (a) first means for forming said first and second product diffracted beams into first and second rectangular beams; (b) second means for forming said first and second rectangular beams into second and third sheet beams, said second and third sheet beams being orthogonal to the plane of said first sheet beam; (c) means to pass only the desired product diffractions within said second and third sheet beams to produce first and second filtered product diffracted sheet beams, said means comprising a pair of slits disposed in the path of said second and third sheet beams; and (d) third means for forming said first and second filtered product diffracted sheet beams into third and fourth rectangular beams.
Claim 13
Dependent Claim
20 words
The device of claim 1, wherein said means for rotating said first and second product diffracted beams comprises dove prisms.
Claim 14
Dependent Claim
25 words
The device of claim 1, wherein: (a) said first product diffracted beam is rotated +90°; and( (b) said second product diffracted beam is rotated -180°.
Claim 15
Dependent Claim
16 words
The device of claim 1, wherein said means to combine said orthogonal comprises a Koester's prism.
Claim 16
Independent Claim
230 words
A method for processing signals to obtain a multi-product, time integrated, correlated output signal, comprising the steps of: (a) expanding a laser light beam into a sheet beam; (b) directing said sheet beam to an acousto-optic medium having an axis and a planar surface extending between opposite first and second ends, so that the sheet beam traverses the medium between the medium ends along and parallel to the medium; (c) propagating a first signal on the planar surface of the acousto-optic medium toward the first end of the acousto-optic medium; (d) propagating a second signal on the planar surface of the acousto-optic medium toward the second end of the acousto-optic medium; (e) propagating a third signal on the planar surface of the acousto-optic medium toward the first end of the acousto-optic medium; (f) propagating a fourth signal on the planar surface of the acousto-optic medium toward the second end of the acousto-optic medium; (g) wherein said first and second signals diffract said sheet beam producing a first, product diffracted beam of light; (h) wherein said third and fourth signals diffract said sheet beam producing a second, product diffracted beam of light; (i) rotating said first product diffracted beam and said second product diffracted beam so that they are orthogonal to each other; (j) combining said orthogonal, product diffracted beams; and (k) directing the combined beam to a time integrating photodetector.
Claim 17
Independent Claim
230 words
A method for processing signals to obtain a multi-product, time integrated, correlated output signal, comprising the steps of: (a) expanding a laser light beam into a sheet beam; (b) directing said sheet beam to an acousto-optic medium having an axis and a planar surface extending between opposite first and second ends, so that the sheet beam traverses the medium between the medium ends along and parallel to the medium; (c) propagating a first signal on the planar surface of the acousto-optic medium toward the first end of the acousto-optic medium; (d) propagating a second signal on the planar surface of the acousto-optic medium toward the second end of the acousto-optic medium; (e) propagating a third signal on the planar surface of the acousto-optic medium toward the first end of the acousto-optic medium; (f) propagating a fourth signal on the planar surface of the acousto-optic medium toward the second end of the acousto-optic medium; (g) wherein said first and second signals diffract said sheet beam producing a first, product diffracted beam of light; (h) wherein said third and fourth signals diffract said sheet beam producing a second, product diffracted beam of light; (i) rotating said first product diffracted beam and said second product diffracted beam so that they are orthogonal to each other; (j) combining said orthogonal, product diffracted beams; and (k) directing the combined beam to a time integrating photodetector.
Claim 18
Dependent Claim
33 words
The method of claim 15, further comprising the step of filtering undesired diffractions produced by the interaction of said sheet beam with said acousto-optic medium and said first, second, third, and fourth signals.
Claim 19
Independent Claim
278 words
A method of obtaining a two-dimensional four product correlation by processing spread spectrum radar signals comprising the steps of: (a) expanding a laser light beam into a sheet beam; (b) directing said sheet beam to an acousto-optic medium having an axis and a planar surface extending between opposite first and second ends, so that the sheet beam traverses the medium between the medium ends along and parallel to the medium; (c) sampling a transmitted radar signal transmitted by a radar transmitter; (d) propagating the sampled transmitted radar signal on the planar surface of the acousto-optic medium toward the first end of the acousto-optic medium; (e) receiving a reflected signal portion of the transmitted radar signal reflected from a target; (f) propagating the reflected signal on the planar surface of the acousto-optic medium toward the second end of the acousto-optic medium; (g) propagating a first linear FM chirp signal on the planar surface of the acousto-optic medium toward the first end of the acousto-optic medium; (h) propagating a second linear FM chirp signal on the planar surface of the acousto-optic medium toward the second end of the acousto-optic medium; (i) wherein said sampled transmitted radar signal and said received reflected signal diffract said sheet beam producing a first, product diffracted beam of light; (j) wherein said first linear FM chirp signal and said second linear FM chirp signal diffract said sheet beam producing a second, product diffracted beam of light; (k) rotating said first product diffracted beam and said second product diffracted beam so that they are orthogonal to each other; (l) combining said orthogonal, product diffracted beams; and (m) directing the combined beams to a time integrating photodetector.
Claim 20
Independent Claim
278 words
A method of obtaining a two-dimensional four product correlation by processing spread spectrum radar signals comprising the steps of: (a) expanding a laser light beam into a sheet beam; (b) directing said sheet beam to an acousto-optic medium having an axis and a planar surface extending between opposite first and second ends, so that the sheet beam traverses the medium between the medium ends along and parallel to the medium; (c) sampling a transmitted radar signal transmitted by a radar transmitter; (d) propagating the sampled transmitted radar signal on the planar surface of the acousto-optic medium toward the first end of the acousto-optic medium; (e) receiving a reflected signal portion of the transmitted radar signal reflected from a target; (f) propagating the reflected signal on the planar surface of the acousto-optic medium toward the second end of the acousto-optic medium; (g) propagating a first linear FM chirp signal on the planar surface of the acousto-optic medium toward the first end of the acousto-optic medium; (h) propagating a second linear FM chirp signal on the planar surface of the acousto-optic medium toward the second end of the acousto-optic medium; (i) wherein said sampled transmitted radar signal and said received reflected signal diffract said sheet beam producing a first, product diffracted beam of light; (j) wherein said first linear FM chirp signal and said second linear FM chirp signal diffract said sheet beam producing a second, product diffracted beam of light; (k) rotating said first product diffracted beam and said second product diffracted beam so that they are orthogonal to each other; (l) combining said orthogonal, product diffracted beams; and (m) directing the combined beams to a time integrating photodetector.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-01-27 | 1989-07-29 | 1990-01-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-01-27 | 1993-07-29 | 1994-01-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-01-27 | 1997-07-29 | 1998-01-28 | $7700.00 | Window Closed / Lapsed |