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US4320474A
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Saturation limited parametric sonar source
Assignee: United States Department of the Navy
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Filing: 1980-11-24
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Granted: 1982-03-16
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Expires: 2000-11-24
Abstract
Abstract A selected increase in the farfield amplitude of the difference frequency am of saturation limited parametric sonar sources is obtained by an array of saturation limited parametric sources having a center-to-center spacing selected such that the primary beams launched by each source coexist in a common region where attenuation has reduced the amplitude of each primary beam to a level which precludes saturation. The selected center-to-center spacing depends upon the number of individual sources implemented and each doubling of the number of selectively spaced sources provides at least a 3 dB increase in the farfield difference frequency amplitude without changing the nominal directivity characteristics of the parametric source.
Inventors
- 👤 John M. Huckabay
- 👤 Reuben H. Wallace
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 13:48
CPC Classifications
B; B06; B06B; B06B1/00; B06B1/02; B06B1/08; B06B1/085
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
144 words
In a saturation limited parametric sonar source operating in a nonlinear medium, that improvement for selectively increasing the farfield difference frequency amplitude of a difference frequency beam of sonic energy produced by said saturation limited parametric sonar source which comprises: a plurality of primary sources having a selected center-to-center spacing each launching a primary beam of sonic energy at least one of said primary beams is a multifrequency beam which is saturation limited, and said center-to-center spacing is selected such that said primary beams first begin to coexist in a common region of said nonlinear medium where spreading and absorption losses reduce the amplitude of said primary beams to a value which precludes saturation; whereby, for each doubling of the number of primary sources implemented, at least a 3 dB increase results in said farfield amplitude of said difference frequency beam of sonic energy.
Claim 2
Dependent Claim
144 words
In a saturation limited parametric sonar source operating in a nonlinear medium, that improvement for selectively increasing the farfield difference frequency amplitude of a difference frequency beam of sonic energy produced by said saturation limited parametric sonar source which comprises: a plurality of primary sources having a selected center-to-center spacing each launching a primary beam of sonic energy at least one of said primary beams is a multifrequency beam which is saturation limited, and said center-to-center spacing is selected such that said primary beams first begin to coexist in a common region of said nonlinear medium where spreading and absorption losses reduce the amplitude of said primary beams to a value which precludes saturation; whereby, for each doubling of the number of primary sources implemented, at least a 3 dB increase results in said farfield amplitude of said difference frequency beam of sonic energy.
Claim 3
Dependent Claim
20 words
The improvement of claim 1, wherein two planar circular transducers of diameter d are spaced apart a distance of 2d.
Claim 4
Dependent Claim
19 words
The improvement of claim 1 wherein 4 circular transducers of diameter d are spaced apart a distance of 4d.
Claim 5
Dependent Claim
36 words
The improvement of claims 2 or 3, wherein each of said transducers is operated in a kd region selected to provide a directive radiation field, where k is the average wave number of the primary frequencies.
Claim 6
Dependent Claim
14 words
The improvement of claim 4, wherein said kd region is greater than about 30.
Claim 7
Independent Claim
72 words
A method providing a selected difference frequency amplitude in the farfield of a saturation limited parametric projector, comprising the steps of: positioning a plurality of parametric sources each of which launches a multifrequency primary beam of sonic energy and at least one of which is saturation limited in a nonlinear medium; and selectively spacing said parametric sources apart in order to preclude saturation in a common region where said primary beams coexist.
Claim 8
Independent Claim
72 words
A method providing a selected difference frequency amplitude in the farfield of a saturation limited parametric projector, comprising the steps of: positioning a plurality of parametric sources each of which launches a multifrequency primary beam of sonic energy and at least one of which is saturation limited in a nonlinear medium; and selectively spacing said parametric sources apart in order to preclude saturation in a common region where said primary beams coexist.
Claim 9
Dependent Claim
24 words
The method of claim 6, further including the step of operating each of said plurality of parametric sources to provide a directional radiation pattern.
Claim 10
Dependent Claim
50 words
Parametric apparatus, comprising: a first circular transducer of diameter d; a second circular transducer of diameter d spaced apart from said first transducer a center-to-center spacing of 2d; and means for driving each of said transducers at at least two selected primary frequencies simultaneously at or just below saturation amplitude.
Claim 11
Dependent Claim
50 words
Parametric apparatus, comprising: a first circular transducer of diameter d; a second circular transducer of diameter d spaced apart from said first transducer a center-to-center spacing of 2d; and means for driving each of said transducers at at least two selected primary frequencies simultaneously at or just below saturation amplitude.
References Cited (Backward Citations)
US3613069A
Cited
US3964013A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-03-15 | 1985-09-14 | 1986-03-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-03-15 | 1989-09-14 | 1990-03-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-03-15 | 1993-09-14 | 1994-03-16 | $7700.00 | Window Closed / Lapsed |