Systems and methods for locating a single reflection on a transmission line

Patent metadata

Field	Value
Publication number	US-10680708-B2
Application number	US-201715481135-A
Country	US
Kind code	B2
Filing date	Apr 6, 2017
Priority date	Apr 6, 2016
Publication date	Jun 9, 2020
Grant date	Jun 9, 2020

Abstract

A system for testing reflections within a data transmission signal includes a data transmission line configured to transmit the signal in a downstream direction, and a test probe configured to electrically contact a contact point on the transmission line and measure a magnitude of a frequency response of the signal therein. The system further includes a spectrum capturing device in operable contact with the test probe, and configured to collect and arrange data of frequency response magnitudes measured by the test probe. The data transmission line includes at least a first impedance mismatch corresponding to a first reflection point along the transmission line, and the spectrum capturing device is configured to determine a severity of the first reflection based on a comparison of a first voltage V1 with a second voltage V2, where V1 represents a DC term, and where V2 represents a reflected energy of a subsequent impulse.

First claim

What is claimed is:

1. A system for testing reflections within an in-service data transmission signal, comprising:
an operational data transmission line configured to transmit the in-service data transmission signal in a downstream direction; and
a test probe configured to electrically contact a contact point on the operational data transmission line, and to measure a magnitude of a frequency response of the in-service data transmission signal from the operational data transmission line;
a spectrum capturing device in operable contact with the test probe, and configured to collect and arrange data of frequency response magnitudes measured by the test probe,
wherein the operational data transmission line includes at least a first impedance mismatch corresponding to a first reflection point along the transmission line, and
wherein the spectrum capturing device is configured to determine a severity of the first reflection based on a comparison of a first voltage V 1 with a second voltage V 2 , where V 1 represents a DC voltage term representing a time domain response of a main impulse of the in-service data transmission signal in the downstream direction, and where V 2 represents a time domain response of a subsequent reflection of the main impulse traveling in the upstream direction.

2. The system of claim 1 , wherein the test probe is disposed at fiber node configured to function as a downstream launch point to make a bi-directional measurement.

3. The system of claim 1 , wherein the operational data transmission line further includes at least one tap, and wherein the test probe is disposed at the at least one tap.

4. The system of claim 3 , wherein the at least one tap comprises a bi-directional directional tap plate.

5. The system of claim 4 , wherein the bi-directional directional tap plate includes one or more of a downstream tap port, and upstream tap port, and a bi-directional tap port.

6. The system of claim 4 , wherein the bi-directional directional tap plate is configured to be removable, and implemented without interfering in the signal being transmitted over the operational data transmission line.

7. The system of claim 1 , wherein the severity of the first reflection is determined according to the formula 20*log(V1/V2).

8. The system of claim 1 , wherein the operational data transmission line further includes at least a second impedance mismatch corresponding to a second reflection point along the transmission line, the second reflection point being different than the first reflection point along the data transmission line.

9. The system of claim 8 , wherein an echo tunnel is formed along the operational data transmission line between the second impedance mismatch and the first impedance mismatch.

10. The system of claim 9 , wherein the test probe is configured to tap the operational data transmission line at point upstream of the echo tunnel.

11. The system of claim 9 , wherein the second reflection from the second impedance mismatch is directly observable by the test probe, and the first reflection from the first impedance mismatch is not directly observable by the test probe.

12. The system of claim 11 , wherein an echo of the first reflection reflecting upstream off of the second impedance mismatch, is observable by the test probe.

Assignees

• Cable Television Laboratories Inc

Inventors

• Williams Thomas H
• Vail Ryan Richard

Classifications

• H04B10/071 Primary

  using a reflected signal, e.g. using optical time domain reflectometers [OTDR] · CPC title

• H04B10/2503

  Electricity · mapped topic

• H04B3/48

  Testing attenuation (H04B3/466 takes precedence) · CPC title

• H04B10/0775

  Performance monitoring and measurement of transmission parameters · CPC title

• H04B10/2589

  Bidirectional transmission · CPC title