US3889073A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Detection of series-resonant circuits connected across transmission paths
Assignee: AT&T Inc
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Filing: 1974-03-06
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Granted: 1975-06-10
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Expires: 1994-03-06
Abstract
Abstract A method and apparatus are disclosed for determining if a series-resonant circuit is connected across a transmission path. A series of rectangular waves having a fundamental component at the resonant frequency of the circuit is applied to the path. The presence of the circuit is indicated by the path current exceeding a predetermined level during the midportions of the rectangular waves.
Inventors
- 👤 Richard Scott Hoppough
- 👤 Herbert Bryant Walker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 14:38
CPC Classifications
H; H04; H04M; H04M3/00; H04M3/22; H04M3/26; H04M3/28; H04M3/30
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
110 words
In a test circuit for detecting an impedance connected across a transmission path by connecting a source of voltage across said path and a current monitoring means in said path, an improvement to enable the detection of an impedance in the form of a seriesresonant circuit, said improvement comprising, said source producing a series of substantially rectangular waves where said waves have a fundamental component at substantially the same frequency as the resonant frequency of said series-resonant circuit, and said current monitoring means sampleS said current to produce an output in response to said current exceeding a predetermined level during the midportion of at least one of said rectangular waves.
Claim 2
Dependent Claim
110 words
In a test circuit for detecting an impedance connected across a transmission path by connecting a source of voltage across said path and a current monitoring means in said path, an improvement to enable the detection of an impedance in the form of a seriesresonant circuit, said improvement comprising, said source producing a series of substantially rectangular waves where said waves have a fundamental component at substantially the same frequency as the resonant frequency of said series-resonant circuit, and said current monitoring means sampleS said current to produce an output in response to said current exceeding a predetermined level during the midportion of at least one of said rectangular waves.
Claim 3
Dependent Claim
85 words
A circuit in accordance with claim 1 in which said sampling current monitoring means comprises, at least one resistor connected in series between said source and said path, first means for comparing the voltage developed across said resistor with a reference voltage and producing an output when the difference between said voltages exceeds a predetermined level, and second means connected to said first means to produce an output in response to the occurrence of said first means output during the midportion of said rectangular waves.
Claim 4
Dependent Claim
90 words
A circuit for determining if a series-resonant circuit is connected across a transmission path, said apparatus comprising, a source for producing a series of substantially rectangular waves where said waves have a fundamental component with a frequency substantially equal to the resonant frequency of said series-resonant circuit, means for applying said waves to said path, and a sampling current monitoring means connected to produce an output indication in response to the current in said path exceeding a predetermined level during the midportion of at least one of said rectangular waves.
Claim 5
Dependent Claim
90 words
A circuit for determining if a series-resonant circuit is connected across a transmission path, said apparatus comprising, a source for producing a series of substantially rectangular waves where said waves have a fundamental component with a frequency substantially equal to the resonant frequency of said series-resonant circuit, means for applying said waves to said path, and a sampling current monitoring means connected to produce an output indication in response to the current in said path exceeding a predetermined level during the midportion of at least one of said rectangular waves.
Claim 6
Dependent Claim
85 words
A circuit in accordance with claim 3 in which said sampling current monitoring means comprises, at least one resistor connected in series between said source and said path, first means for comparing the voltage developed across said resistor with a reference voltage and producing an output when the difference between said voltages exceeds a predetermined level, and second means connected to said first means to produce an output in response to the occurrence of said first means output during the midportion of said rectangular waves.
Claim 7
Independent Claim
77 words
A method for detecting a series-resonant circuit connected across a transmission path comprising the steps of applying at least one wave of a series of substantially rectangular waves to said path where the fundamental component of said waves has a frequency substantially equal to that at which said series-resonant circuit resonates, and producing an output indication when the current in said path during the midportion of at least one of said rectangular waves exceeds a predetermined level.
Claim 8
Independent Claim
77 words
A method for detecting a series-resonant circuit connected across a transmission path comprising the steps of applying at least one wave of a series of substantially rectangular waves to said path where the fundamental component of said waves has a frequency substantially equal to that at which said series-resonant circuit resonates, and producing an output indication when the current in said path during the midportion of at least one of said rectangular waves exceeds a predetermined level.
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) | 1978-06-09 | 1978-12-09 | 1979-06-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-09 | 1982-12-09 | 1983-06-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-09 | 1986-12-09 | 1987-06-10 | $7700.00 | Window Closed / Lapsed |