US3617880A
Expired / Lapsed
US
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Time domain reflectometer
Assignee: Nortel Networks Ltd
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Filing: 1970-05-15
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Granted: 1971-11-02
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Expires: 1990-05-15
Abstract
Abstract A typical sampling time domain reflectometer (T.D.R.) apparatus is modified by the addition of an integrator which can be selectively switched into and out of the vertical signal path. The integrator is utilized to integrate signals reflected from any reactive discontinuity in a transmission line under test. The amplitude of the integrated signal is utilized to enable the accurate determination of the reflection coefficient. The derived results are substantially unaffected by variations in the rise time of the step function signal. In addition, the apparatus'' independence from the step function signal rise time enables the use of a longer rise time and thus the system''s bandwidth requirement is lessened to the point where a real time T.D.R. apparatus may be utilized.
Inventors
- 👤 George D Cormack
- 👤 Ronald P Manning
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:18
CPC Classifications
H; H04; H04B; H04B3/00; H04B3/02; H04B3/46; G; G01; G01R; G01R27/00; G01R27/28; G01R27/32; G01R31/00; G01R31/08; G01R31/11
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
130 words
A time domain reflectometer apparatus for measuring the reflection coefficient of at least one reactive discontinuity in a transmission line, the apparatus comprising: means for applying an incident step function signal to one end of the transmission line, means for integrating at least one signal reflected from the transmission line, means for displaying the incident step function signal and integrated signal so as to determine the reflection coefficient from the formula where: Gamma is the reflection coefficient of the discontinuity, f is the frequency at which the reflection coefficient measurement is desired, As iS the amplitude of the incident step function signal, Ai is the amplitude of the integrated signal, Zo is the characteristic impedance of the transmission line, Zg is the impedance of the incident step function signal source.
Claim 2
Dependent Claim
130 words
A time domain reflectometer apparatus for measuring the reflection coefficient of at least one reactive discontinuity in a transmission line, the apparatus comprising: means for applying an incident step function signal to one end of the transmission line, means for integrating at least one signal reflected from the transmission line, means for displaying the incident step function signal and integrated signal so as to determine the reflection coefficient from the formula where: Gamma is the reflection coefficient of the discontinuity, f is the frequency at which the reflection coefficient measurement is desired, As iS the amplitude of the incident step function signal, Ai is the amplitude of the integrated signal, Zo is the characteristic impedance of the transmission line, Zg is the impedance of the incident step function signal source.
Claim 3
Dependent Claim
174 words
A time domain reflectometer apparatus for measuring the reflection coefficient of at least one reactive discontinuity in a transmission line, the apparatus comprising: means for applying incident step function signals to one end of the transmission line, means for sampling the incident step function signals and for sampling signals reflected from the transmission line, means for integrating the samples of the signals reflected, means for displaying the samples of the incident step function signal and for displaying the integration of the samples of the signals reflected from the reactive discontinuity in the transmission line so as to determine the reflection coefficient from the formula where: Gamma is the reflection coefficient of at least one discontinuity, f is the frequency at which the reflection coefficient measurement is desired, As is the amplitude of the incident step function signal, Ai is the amplitude of the integrated signal, Zo is the characteristic impedance of the transmission line, Zg is the impedance of the incident step function signal source, tr is real time, ts is horizontal sweep time.
Claim 4
Dependent Claim
174 words
A time domain reflectometer apparatus for measuring the reflection coefficient of at least one reactive discontinuity in a transmission line, the apparatus comprising: means for applying incident step function signals to one end of the transmission line, means for sampling the incident step function signals and for sampling signals reflected from the transmission line, means for integrating the samples of the signals reflected, means for displaying the samples of the incident step function signal and for displaying the integration of the samples of the signals reflected from the reactive discontinuity in the transmission line so as to determine the reflection coefficient from the formula where: Gamma is the reflection coefficient of at least one discontinuity, f is the frequency at which the reflection coefficient measurement is desired, As is the amplitude of the incident step function signal, Ai is the amplitude of the integrated signal, Zo is the characteristic impedance of the transmission line, Zg is the impedance of the incident step function signal source, tr is real time, ts is horizontal sweep time.
Claim 5
Independent Claim
125 words
A method of measuring the reflection coefficient of at least one reactive discontinuity in a transmission line, comprising the steps of: a. applying an incident step function signal to one end of the transmission line, b. integrating at least one signal reflected from the transmission line, c. displaying the incident step function signal and the integrated signal to determine the reflection coefficient from the formula where: Gamma is the reflection coefficient of the reactive discontinuity, f is the frequency at which the reflection coefficient measurement is desired, As is the amplitude of the incident step function signal, Ai is the amplitude of the integrated signal, Zo is the characteristic impedance of the transmission line, Zg is the impedance of the incident step function signal source.
Claim 6
Independent Claim
125 words
A method of measuring the reflection coefficient of at least one reactive discontinuity in a transmission line, comprising the steps of: a. applying an incident step function signal to one end of the transmission line, b. integrating at least one signal reflected from the transmission line, c. displaying the incident step function signal and the integrated signal to determine the reflection coefficient from the formula where: Gamma is the reflection coefficient of the reactive discontinuity, f is the frequency at which the reflection coefficient measurement is desired, As is the amplitude of the incident step function signal, Ai is the amplitude of the integrated signal, Zo is the characteristic impedance of the transmission line, Zg is the impedance of the incident step function signal source.
Claim 7
Independent Claim
165 words
The method of measuring the reflection coefficient of at least one discontinuity in a transmission line, comprising the steps of: a. applying incident step function signals to one end of the transmission line, b. sampling the incident step function signals and signals reflected from the reactive discontinuity in the transmission line, c. integrating the samples of signals reflected from the transmission line, d. displaying the samples of the incident step function signals and the integrated samples of the signals reflected from the reactive discontinuity in the transmission line to determine the reflection coefficient from the formula where: Gamma is the reflection coefficient of the reactive discontinuity, f is the frequency at which the reflection coefficient measurement is desired, As is the amplitude of the incident step function signal, Ai is the amplitude of the integrated signal, Zo is the characteristic impedance of the transmission line, Zg is the impedance of the incident step function signal source, tr is real time, ts is horizontal sweep time.
Claim 8
Independent Claim
165 words
The method of measuring the reflection coefficient of at least one discontinuity in a transmission line, comprising the steps of: a. applying incident step function signals to one end of the transmission line, b. sampling the incident step function signals and signals reflected from the reactive discontinuity in the transmission line, c. integrating the samples of signals reflected from the transmission line, d. displaying the samples of the incident step function signals and the integrated samples of the signals reflected from the reactive discontinuity in the transmission line to determine the reflection coefficient from the formula where: Gamma is the reflection coefficient of the reactive discontinuity, f is the frequency at which the reflection coefficient measurement is desired, As is the amplitude of the incident step function signal, Ai is the amplitude of the integrated signal, Zo is the characteristic impedance of the transmission line, Zg is the impedance of the incident step function signal source, tr is real time, ts is horizontal sweep time.
References Cited (Backward Citations)
US2649570A
Cited
US3535628A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-01 | 1975-05-03 | 1975-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-01 | 1979-05-03 | 1979-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-01 | 1983-05-03 | 1983-11-02 | $7700.00 | Window Closed / Lapsed |