US3663769A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for testing a communication line
Assignee: Northeast Electronics Corp
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Filing: 1969-07-25
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Granted: 1972-05-16
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Expires: 1989-07-25
Abstract
Abstract Testing of a communication line is accomplished by disposing a voltage controlled oscillator, e.g., a gas tube relaxation type, across the line at a distant point and applying a DC voltage to the line at a near point of sufficient magnitude to initiate oscillator operation, the AC signal generated by the oscillator being detected, and analyzed if desired, at the near point.
Inventors
- 👤 John T Boatwright
- 👤 Donald L Knight
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 19:10
CPC Classifications
H; H04; H04M; H04M3/00; H04M3/22; H04M3/26; H04M3/28; H04M3/30; H04M3/301; H04B; H04B3/00; H04B3/02; H04B3/46
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
128 words
A system for testing between two distant points an interconnecting communication line which is capable of cummunicating therebetween a DC voltage and an AC signal, said system comprising in combination: voltage controlled oscillator means permanently connected across said line at one of said points, said oscillator means being insensitive to low DC voltage but being triggerable into oscillation by the application of a DC voltage thereto from said line in excess of predetermined magnitude for generating and applying a characteristic AC signal to said line, said oscillations continuing so long as said excess DC voltage is applied to said line; and test control means arranged to be coupled to said line at the other of said points, said test control means including means for detecting said characteristic signal.
Claim 2
Independent Claim
128 words
A system for testing between two distant points an interconnecting communication line which is capable of cummunicating therebetween a DC voltage and an AC signal, said system comprising in combination: voltage controlled oscillator means permanently connected across said line at one of said points, said oscillator means being insensitive to low DC voltage but being triggerable into oscillation by the application of a DC voltage thereto from said line in excess of predetermined magnitude for generating and applying a characteristic AC signal to said line, said oscillations continuing so long as said excess DC voltage is applied to said line; and test control means arranged to be coupled to said line at the other of said points, said test control means including means for detecting said characteristic signal.
Claim 3
Dependent Claim
34 words
A system according to claim 1, wherein said oscillator means comprises a relaxation oscillator circuit employing an electron device having a negative resistance characteristic between a breakdown voltage point and a sustaining voltage point.
Claim 4
Dependent Claim
36 words
A system according to claim 2, wherein said oscillator means comprises a parallel resistance and capacitance time constant circuit connected in series with said electron device across said line, said electron device being a semi-conductor device.
Claim 5
Dependent Claim
30 words
A system according to claim 1, wherein said oscillator means comprises a parallel resistance and capacitance time constant circuit connected in series with a gaseous discharge device across said line.
Claim 6
Dependent Claim
55 words
A system according to claim 1, wherein said DC voltage applying means comprises a source of DC voltage in excess of said predetermined magnitude, and means for selectably connecting said source across said line; and wherein said detecting means comprises an AC signal detector, and DC decoupling means for interconnecting said detector across said line.
Claim 7
Dependent Claim
103 words
A system according to claim 1, wherein said test control means comprises a source of DC voltage in excess of said predetermined magnitude, a pair of terminals for connecting the test control means to said line, a separate resistor connected at one end to a corresponding one of said terminals, means for selectably connecting said source of D.C. voltage between the free ends of said resistors, and a series circuit connected between said terminals, said series circuit including in sequence a first capacitor, a parallel network of an A.C. detector and a pair of oppositely poled unidirectionally conductive devices, and a second capacitor.
Claim 8
Dependent Claim
50 words
A system according to claim 1, wherein said DC voltage applying means comprises a stable voltage-regulated current-limited source of DC voltage in excess of said predetermined magnitude, and means for selectably connecting said source across said line; and wherein said detecting means comprises a calibrated AC signal level measuring device.
Claim 9
Dependent Claim
53 words
A system according to claim 7, wherein said oscillator means comprises a relaxation oscillator circuit of the type which shifts from the dormant to the oscillatory state during the application thereto of a DC voltage in excess of said predetermined magnitude and amplitude modulates the current flowing through it while it is oscillating.
Claim 10
Independent Claim
210 words
A system for testing between two distant points an interconnecting communication line which is capable of communicating therebetween a DC voltage and an A.C. signal, said system comprising in combination: voltage controlled oscillator means coupled across said line at one of Said points, said oscillator means being insensitive to low DC voltage but being triggerable into oscillation by the application of a DC voltage thereto from said line in excess of a predetermined magnitude for generating and applying a characteristic AC signal to said line; and test control means arranged to be coupled to said line at the other of said points, said test control means including means for selectably applying to said line a DC voltage in excess of said predetermined magnitude, and means for detecting said characteristic signal, said test control means comprising a stable voltage-regulated current-limited source of DC voltage in excess of said predetermined magnitude, a signal transformer having primary and secondary windings, means connecting said source of DC voltage in series with said primary winding for connection across said line, a high pass filter, an absolute average level measuring circuit, and means coupling said secondary winding to an input of said filter and an output of said filter to an input of said measuring circuit.
Claim 11
Independent Claim
210 words
A system for testing between two distant points an interconnecting communication line which is capable of communicating therebetween a DC voltage and an A.C. signal, said system comprising in combination: voltage controlled oscillator means coupled across said line at one of Said points, said oscillator means being insensitive to low DC voltage but being triggerable into oscillation by the application of a DC voltage thereto from said line in excess of a predetermined magnitude for generating and applying a characteristic AC signal to said line; and test control means arranged to be coupled to said line at the other of said points, said test control means including means for selectably applying to said line a DC voltage in excess of said predetermined magnitude, and means for detecting said characteristic signal, said test control means comprising a stable voltage-regulated current-limited source of DC voltage in excess of said predetermined magnitude, a signal transformer having primary and secondary windings, means connecting said source of DC voltage in series with said primary winding for connection across said line, a high pass filter, an absolute average level measuring circuit, and means coupling said secondary winding to an input of said filter and an output of said filter to an input of said measuring circuit.
Claim 12
Independent Claim
233 words
A system for testing between two distant points an interconnecting communication line which is capable of communicating therebetween a DC voltage and an AC signal, said system comprising in combination: voltage controlled oscillator means coupled across said line at one of said points, said oscillator means being insensitive to low DC voltage but being triggerable into oscillation by the application of a DC voltage thereto from said line in excess of a predetermined magnitude for generating and applying a characteristic AC signal to said line; and test control means arranged to be coupled to said line at the other of said points, said test control means including means for selectably applying to said line a DC voltage in excess of said predetermined magnitude, and means for detecting said characteristic signal, said oscillator means being of the type that oscillates at a frequency which is a function of the applied DC voltage, and wherein said test control means comprises an adjustable source of DC voltage coupled across said line, a local oscillator, means for comparing the phase said characteristic AC signal as received at said other point of said line with an output from said local oscillator and controlling said source of voltage in a direction to maintain a substantially fixed phase relationship between AC signal and said output from the local oscillator, and means for measuring a parameter of said received AC signal.
Claim 13
Independent Claim
233 words
A system for testing between two distant points an interconnecting communication line which is capable of communicating therebetween a DC voltage and an AC signal, said system comprising in combination: voltage controlled oscillator means coupled across said line at one of said points, said oscillator means being insensitive to low DC voltage but being triggerable into oscillation by the application of a DC voltage thereto from said line in excess of a predetermined magnitude for generating and applying a characteristic AC signal to said line; and test control means arranged to be coupled to said line at the other of said points, said test control means including means for selectably applying to said line a DC voltage in excess of said predetermined magnitude, and means for detecting said characteristic signal, said oscillator means being of the type that oscillates at a frequency which is a function of the applied DC voltage, and wherein said test control means comprises an adjustable source of DC voltage coupled across said line, a local oscillator, means for comparing the phase said characteristic AC signal as received at said other point of said line with an output from said local oscillator and controlling said source of voltage in a direction to maintain a substantially fixed phase relationship between AC signal and said output from the local oscillator, and means for measuring a parameter of said received AC signal.
Claim 14
Dependent Claim
30 words
A system according to claim 10, wherein a phase measuring circuit is provided for measuring the phase difference between said received AC signal and said output from the local oscillator.
Claim 15
Dependent Claim
22 words
A system according to claim 10, wherein an amplitude measuring circuit is provided for measuring the amplitude of said received AC signal.
Claim 16
Dependent Claim
29 words
A system according to claim 11, wherein an adjustable bandpass filter is interposed between said line and said phase measuring circuit for restricting the measurement to a selectable frequency.
Claim 17
Dependent Claim
29 words
A system according to claim 12, wherein an adjustable bandpass filter is interposed between said line and said amplitude measuring circuit for restricting the measurement to a selectable frequency.
Claim 18
Independent Claim
178 words
A system for testing a telephone line between a near test point and a distant telephone set without interfering with the normal communication traffic thereon comprising in combination voltage controlled oscillator means connected across said line at said telephone set, said oscillator means being insensitive to low DC voltage but being triggerable into oscillation by the application of a DC voltage thereto from said line in excess of a predetermined magnitude for generating and applying a characteristic AC signal to said line, said predetermined magnitude being in excess of the maximum voltage normally present on the line and said characteristic AC signal being incapable of initiating a ringing function in said teLephone set; and test control means arranged to be coupled to said line at said near test point, said test control means including a source of DC voltage in excess of said predetermined magnitude, means for coupling said source to said line, and means for detecting said characteristic signal, the arrangement being such that an off-hook condition of said telephone set prevents triggering of said oscillator means.
Claim 19
Independent Claim
178 words
A system for testing a telephone line between a near test point and a distant telephone set without interfering with the normal communication traffic thereon comprising in combination voltage controlled oscillator means connected across said line at said telephone set, said oscillator means being insensitive to low DC voltage but being triggerable into oscillation by the application of a DC voltage thereto from said line in excess of a predetermined magnitude for generating and applying a characteristic AC signal to said line, said predetermined magnitude being in excess of the maximum voltage normally present on the line and said characteristic AC signal being incapable of initiating a ringing function in said teLephone set; and test control means arranged to be coupled to said line at said near test point, said test control means including a source of DC voltage in excess of said predetermined magnitude, means for coupling said source to said line, and means for detecting said characteristic signal, the arrangement being such that an off-hook condition of said telephone set prevents triggering of said oscillator means.
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) | 1975-05-16 | 1975-11-15 | 1976-05-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-16 | 1979-11-15 | 1980-05-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-16 | 1983-11-15 | 1984-05-16 | $7700.00 | Window Closed / Lapsed |