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Patent US3864528A successfully refreshed from Google Patents.
US3864528A
Expired / Lapsed
US
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Fault locating system for a digital transmission system
Assignee: Nortel Networks Technology Corp
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Filing: 1973-08-22
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Granted: 1975-02-04
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Expires: 1993-08-22
Abstract
Abstract A system for testing line repeaters in a digital transmission system in which a limited number of test signal frequencies are available. By providing switched amplifiers appending each of the line repeaters which are responsive to a powering voltage of a selective magnitude and polarity, quadruple the number of line repeaters can be tested using a single test line.
Inventors
- 👤 Jan Heynen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 07:22
CPC Classifications
H; H04; H04B; H04B17/00; H04B17/40; H04B17/401; H04B17/402; H04B17/404
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
277 words
A fault locating system for a bipolar digital transmission system including first and second transmission lines having pairs of line repeaters serially connected in opposite directions at adjacent intervals therealong; a frequency selective filter circuit at each location connected to the outputs of the pair of line repeaters for monitoring the performance thereof, the circuits being divided into two groups which are responsive to corresponding test frequencies, each of the frequencies being unique within a group; means for transmitting a bipolar test signal along said first transmission line having recurrent unipolar pulses at one of said test frequencies; a common fault locate line connected to a signal output of each of said frequency selective filter circuits; means for powering said circuits from said common fault locate line; each of said frequency selective filter circuits including a control means to actuate the circuits in one group only when the powering voltage is below a selected value and to actuate the circuits in the other group only when the powering voltage is above said selected value; each of said frequency selective circuits also including means for selecting the output of one or the other of the pair of line repeaters connected thereto in response to the d-c polarity of the powering voltage connected to said common fault locate line; means for detecting errors in the bipolar signal being received at the end of said first transmission line; means for detecting the d-c powering voltage on the common fault locate line; and means responsive to the error detector and the voltage detector for routing the output of the first transmission line back to the input of the second transmission line.
Claim 2
Dependent Claim
277 words
A fault locating system for a bipolar digital transmission system including first and second transmission lines having pairs of line repeaters serially connected in opposite directions at adjacent intervals therealong; a frequency selective filter circuit at each location connected to the outputs of the pair of line repeaters for monitoring the performance thereof, the circuits being divided into two groups which are responsive to corresponding test frequencies, each of the frequencies being unique within a group; means for transmitting a bipolar test signal along said first transmission line having recurrent unipolar pulses at one of said test frequencies; a common fault locate line connected to a signal output of each of said frequency selective filter circuits; means for powering said circuits from said common fault locate line; each of said frequency selective filter circuits including a control means to actuate the circuits in one group only when the powering voltage is below a selected value and to actuate the circuits in the other group only when the powering voltage is above said selected value; each of said frequency selective circuits also including means for selecting the output of one or the other of the pair of line repeaters connected thereto in response to the d-c polarity of the powering voltage connected to said common fault locate line; means for detecting errors in the bipolar signal being received at the end of said first transmission line; means for detecting the d-c powering voltage on the common fault locate line; and means responsive to the error detector and the voltage detector for routing the output of the first transmission line back to the input of the second transmission line.
Claim 3
Dependent Claim
183 words
A fault locating system for a digital transmission system including first and second transmission lines having pairs of line repeaters serially connected in opposite directions at adjacent intervals along said lines, said system comprising: a frequency selective filter circuit connected to the output of each of said line repeaters for monitoring the performance thereof, the circuits being divided into two groups which are responsive to corresponding test frequencies, each of the frequencies being unique within a group; means for transmitting a test signal along said transmission line at one of said test frequencies; a common fault locate line connected to a signal output of each of said frequency selective filter circuits; means for powering said circuits from said common fault locate line; and means responsive to the detection of a predetermined number of errors on the incoming signal from the first transmission line and to the detection of power on said common fault locate line for gating the signal onto the input of the sEcond transmission line; whereby testing of either of said lines can be accomplished from one terminal of said lines.
Claim 4
Dependent Claim
183 words
A fault locating system for a digital transmission system including first and second transmission lines having pairs of line repeaters serially connected in opposite directions at adjacent intervals along said lines, said system comprising: a frequency selective filter circuit connected to the output of each of said line repeaters for monitoring the performance thereof, the circuits being divided into two groups which are responsive to corresponding test frequencies, each of the frequencies being unique within a group; means for transmitting a test signal along said transmission line at one of said test frequencies; a common fault locate line connected to a signal output of each of said frequency selective filter circuits; means for powering said circuits from said common fault locate line; and means responsive to the detection of a predetermined number of errors on the incoming signal from the first transmission line and to the detection of power on said common fault locate line for gating the signal onto the input of the sEcond transmission line; whereby testing of either of said lines can be accomplished from one terminal of said lines.
Claim 5
Dependent Claim
97 words
A fault locating system as defined in claim 2 in which: each of said frequency selective filter circuits includes control means to actuate the circuits in one group only when the powering voltage is below a selected value and to actuate the circuits in the other group only when the powering voltage is above said selected value; and each filter circuit additionally includes means for selecting the output of one or the other of the two line repeaters connected thereto in response to the d-c polarity of the powering voltage connected to said common fault locate line.
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) | 1978-02-03 | 1978-08-05 | 1979-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-03 | 1982-08-05 | 1983-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-03 | 1986-08-05 | 1987-02-04 | $7700.00 | Window Closed / Lapsed |