US3626282A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for locating shunt faults in a cable utilizing the fault as a noise source
Assignee: AT&T Inc
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Filing: 1970-03-02
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Granted: 1971-12-07
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Expires: 1990-03-02
Abstract
Abstract Shunt faults are located in a communications cable by turning to account the noise properties of the fault. Bias power supplied to a cable is adjusted to maximize the noise generated at the fault. Noise measurements are made at each of the cable terminals at predetermined frequencies. The noise measurements are utilized in conjunction with the preestablished transmission levels in the cable to obtain a measure of the distance to the fault from a cable terminal.
Inventors
- 👤 Sherman Theodore Brewer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 20:34
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/08
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
104 words
A method for locating shunt faults in a transmission cable system having preestablished transmission levels comprising the steps of, adjusting power supplied to the cable to maximize noise power generated at a shunt fault, making a first noise power measurement during said maximum noise condition at a first predetermined location along said cable, making a second noise power measurement during said maximum noise condition at a second predetermined location along said cable, and utilizing said first and second measured noise power values in conjunction with said preestablished transmission values as a measure of the position of the fault between said first and second locations.
Claim 2
Independent Claim
104 words
A method for locating shunt faults in a transmission cable system having preestablished transmission levels comprising the steps of, adjusting power supplied to the cable to maximize noise power generated at a shunt fault, making a first noise power measurement during said maximum noise condition at a first predetermined location along said cable, making a second noise power measurement during said maximum noise condition at a second predetermined location along said cable, and utilizing said first and second measured noise power values in conjunction with said preestablished transmission values as a measure of the position of the fault between said first and second locations.
Claim 3
Dependent Claim
106 words
The method as defined in claim 1 further including the steps of, adjusting the power supplied to said cable to minimize noise power generated at said fault, making a third noise power measurement during said minimum noise condition at said first location along said cable, making a fourth noise power measurement during said minimum noise condition at said second location along said cable, and utilizing said third and fourth noise power measurements in conjunction with said first and second noise power measurements and said preestablished transmission levels as a measure of the position of said fault between said first and second predetermined locations along said cable.
Claim 4
Dependent Claim
63 words
A method as defined in claim 2 wherein said first and second locations are first and second terminals of the cable, respectively, and wherein said first and third noise power measurements are made at a first predetermined frequency and said second and fourth noise power measurements are made at a second predetermined frequency, said frequencies being in the transmission passbands of said cable.
Claim 5
Dependent Claim
164 words
The method as defined in claim 3 wherein said transmission levels and said noise measurement values represent the position of the fault from said first terminal in accordance with the relationship where D is the distance in nautical miles between the cable terminals, d is the distance in nautical miles from the first terminal to the fault, P1 is the net noise power in the first frequency band measured at said first cable terminal due to the fault (the first noise power measurement minus the third noise powEr measurement), Ph is the net noise power in the second frequency band measured at said second cable terminal due to the fault (the second noise power measurement minus the fourth noise power measurement), L1 and L2 are the cable transmission power levels in the first frequency band at the first and second terminals, respectively, and L3 and L4 are the cable transmission power levels in the second frequency band at the second and first terminals, respectively.
Claim 6
Independent Claim
199 words
A method for locating shunt faults in a communication cable system including a plurality of equally spaced repeaters, each repeater having preestablished signal transmission power levels in first and second frequency bands, comprising the steps of, adjusting the bias power supplied to the cable to minimize noise power generated at a fault, making a first noise power measurement during said minimum fault noise condition at a first predetermined frequency at a first terminal of said cable, making a second noise power measurement during said minimum fault noise condition at a second predetermined frequency at a second terminal of said cable, said second frequency being related to said first frequency by the frequency spacing between the first and second frequency bands, adjusting the bias power supplied to the cable to maximize noise power generated at the fault, making a third noise power measurement during said maximum fault noise condition at said first terminal, making a fourth noise power measurement during said maximum noise condition at said second predetermined frequency at said second terminal, and utilizing said measured noise power values in conjunction with said preestablished transmission levels as a measure of the position of the fault between two adjacent repeaters.
Claim 7
Independent Claim
199 words
A method for locating shunt faults in a communication cable system including a plurality of equally spaced repeaters, each repeater having preestablished signal transmission power levels in first and second frequency bands, comprising the steps of, adjusting the bias power supplied to the cable to minimize noise power generated at a fault, making a first noise power measurement during said minimum fault noise condition at a first predetermined frequency at a first terminal of said cable, making a second noise power measurement during said minimum fault noise condition at a second predetermined frequency at a second terminal of said cable, said second frequency being related to said first frequency by the frequency spacing between the first and second frequency bands, adjusting the bias power supplied to the cable to maximize noise power generated at the fault, making a third noise power measurement during said maximum fault noise condition at said first terminal, making a fourth noise power measurement during said maximum noise condition at said second predetermined frequency at said second terminal, and utilizing said measured noise power values in conjunction with said preestablished transmission levels as a measure of the position of the fault between two adjacent repeaters.
Claim 8
Dependent Claim
170 words
The method as defined in claim 5 wherein said transmission power levels and said measured noise power values represent the position of the fault in a cable section between first and second successive repeaters in accordance with the relationship where D is the distance in nautical miles between the successive repeaters, d is the distance in nautical miles from the first repeater to the fault, P1 is the net noise power in the first frequency band due to the fault measured at the first cable terminal (third noise power measurement minus first noise power measurement), Ph is the net noise power in the second frequency band due to the fault measured at the second cable terminal (the fourth noise power measurement minus the second noise power measurement), L1 and L2 are the cable transmission power levels in the first frequency band at the first and second repeaters, respectively, and L3 and L4 are the cable transmission power levels in the second frequency band at the second and first repeaters, respectively.
References Cited (Backward Citations)
US2580097A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-06 | 1975-06-07 | 1975-12-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-06 | 1979-06-07 | 1979-12-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-06 | 1983-06-07 | 1983-12-07 | $7700.00 | Window Closed / Lapsed |