US3860899A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Strum noise reducing device
Assignee: United States Department of the Navy
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Filing: 1968-10-08
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Granted: 1975-01-14
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Expires: 1988-10-08
Abstract
Abstract A device for reducing noise in a towed hydrophone system caused by cable strum is provided by producing a signal that is proportional to the strum signal but is uninfluenced by the acoustic signal. A geophone, an accelerometer or a strain gauge may be suitably positioned to be sensitive only to the distortion caused by cable strum. The strum signal thus detected is introduced in opposition to the combined acoustic and strum signal received by the hydrophone so that strum noise in the acoustic signal is erased or substantially deleted.
Inventors
- 👤 Francis W Watlington
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 12:27
CPC Classifications
G; G01; G01V; G01V1/00; G01V1/16; G01V1/20; G01V1/201; G01S; G01S1/00; G01S1/72; Y; Y10; Y10S; Y10S367/00; Y10S367/901
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
161 words
A noise reducing device for substantially reducing or eliminating strum noise occasioned by towing by ship of underwater objects comprising: a tow cable secured at one end to a towing ship; a hydrophone housing secured at the other end of said tow cable, said housing having a centrally disposed cavity and a viscous fluid in said cavity; a hydrophone positioned axially in said cavity by a forwardly extending conductive connector and a rearwardly extending nonconductive connector, said conductive connector extending to said ship through the forward end of said housing, said nonconductive connector connected to the aft end of said housing; cable strum sensing and transducing means in said cavity connected to said hydrophone and said housing for producing an electric signal proportional to the strum of said cable; and means for introducing said electric signal in opposition to the electric signals generated in said hydrophone so that strum noise signals in the signal output of said hydrophone are substantially eliminated.
Claim 2
Dependent Claim
161 words
A noise reducing device for substantially reducing or eliminating strum noise occasioned by towing by ship of underwater objects comprising: a tow cable secured at one end to a towing ship; a hydrophone housing secured at the other end of said tow cable, said housing having a centrally disposed cavity and a viscous fluid in said cavity; a hydrophone positioned axially in said cavity by a forwardly extending conductive connector and a rearwardly extending nonconductive connector, said conductive connector extending to said ship through the forward end of said housing, said nonconductive connector connected to the aft end of said housing; cable strum sensing and transducing means in said cavity connected to said hydrophone and said housing for producing an electric signal proportional to the strum of said cable; and means for introducing said electric signal in opposition to the electric signals generated in said hydrophone so that strum noise signals in the signal output of said hydrophone are substantially eliminated.
Claim 3
Dependent Claim
40 words
The device as defined in claim 1 wherein said sensing means is connected in series between said hydrophone and said ship; and means in said cavity isolating said sensing means from the acoustic signals which are received by said hydrophone.
Claim 4
Dependent Claim
82 words
The device as defined in claim 2 wherein said sensing means is positioned in the forward end of said cavity, said hydrophone housing including a nose sectiOn and a tail section spaced apart by an intermediate sleeve member all of compliant material, said sleeve member and said nose and tail sections forming said cavity, said sheath disposed adjacent the interior surface of said sleeve and extending rearward from the aft end of said nose section so as to encircle said sensing means.
Claim 5
Dependent Claim
14 words
The device as defined in claim 3 wherein said sensing means is a geophone.
Claim 6
Dependent Claim
14 words
The device as defined in claim 3 wherein said sensing means is an accelerometer.
Claim 7
Dependent Claim
28 words
The device as defined in claim 3 wherein said sensing means is a strain gauge positioned so as to be sensitive to the distortion caused by cable strum.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-01-13 | 1978-07-15 | 1979-01-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-13 | 1982-07-15 | 1983-01-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-13 | 1986-07-15 | 1987-01-14 | $7700.00 | Window Closed / Lapsed |