Cable diagnostics for Base-T systems

Patent metadata

Field	Value
Publication number	US-9103869-B2
Application number	US-201313914215-A
Country	US
Kind code	B2
Filing date	Jun 10, 2013
Priority date	Dec 10, 2008
Publication date	Aug 11, 2015
Grant date	Aug 11, 2015

Abstract

A method includes generating a pulse, transmitting the pulse on a first cable of a multi-cable communication system, monitoring a second cable of the multi-cable communication system for the pulse or a reflection of the pulse on the second cable, and, if the monitoring detects the pulse or the reflection on the second cable, outputting a notification of a short between the first cable and the second cable.

First claim

The invention claimed is:

1. A method, comprising:
generating a pulse;
transmitting the pulse on a first cable of a multi-cable communication system;
monitoring the first cable to detect a first reflection of the pulse on the first cable, including using a first high-pass filter with a first corner frequency;
determining whether the first cable is faulty based on an amplitude of the first reflection;
monitoring a second cable of the multi-cable communication system to detect whether the pulse or a second reflection of the pulse appears on the second cable of the multi-cable communication system, wherein detecting whether the pulse or the reflection of the pulse appears on the second cable includes using a second high-pass filter with a second corner frequency lower than the first corner frequency of the first high-pass filter; and
responsive to the pulse or the second reflection of the pulse being detected to appear on the second cable of the multi-cable communication system,
outputting a notification of a short between (i) the first cable of the multi-cable communication system and (ii) the second cable of the multi-cable communication system.

2. The method of claim 1 , wherein responsive to the pulse or the second reflection of the pulse being detected to appear on the second cable of the multi-cable communication system, the method further comprises:
calculating a time duration between (i) transmitting the pulse on the first cable of the multi-cable communication system and (ii) receiving the pulse or the second reflection of the pulse on the second cable of the multi-cable communication system; and
calculating a distance to the short based on the time duration and the speed of the pulse within the first cable of the multi-cable communication system.

3. The method of claim 2 , further comprising:
calculating a time duration between transmitting the pulse on the first cable and receiving the first reflection on the first cable; and
calculating a distance to the first cable end or the fault based on (i) the time duration between (a) transmitting the pulse on the first cable and (b) receiving the first reflection on the first cable, and (ii) a speed of the pulse within the first cable.

4. The method of claim 1 , wherein the multi-cable communication system comprises and Ethernet communication system utilizing four twisted pair cables including the first cable and the second cable.

5. The method of claim 4 , further comprising repeating monitoring and outputting for a third cable and a fourth cable in connection with detecting shorts between the first cable and each of the third cable and the fourth cable.

6. The method of claim 5 , further comprising repeating the method for each cable in the four twisted pair cables.

7. The method of claim 1 , wherein the pulse comprises a 100 nanosecond pulse.

8. An apparatus, comprising:
a transmitter configured to couple communicatively to a first cable of a multi-cable communication system;
a receiver configured to couple communicatively to the first cable and a second cable of the multi-cable communication system; and
a processor configured to
cause the transmitter to transmit a pulse on the first cable of the multi-cable communication system,
monitor a first signal received via the first cable to detect a first reflection of the pulse on the first cable, including using a first high-pass filter with a first corner frequency,
determine whether the first cable is faulty based on an amplitude of the first reflection,
monitor a second signal received via the second cable to determine whether the pulse or a second reflection of the pulse is received by the receiver on the second cable of the multi-cable communication system, wherein determining whether the pulse or the reflection of the pulse is received by the receiver on the second cable includes using a second high-pass filter with a second corner frequency lower than the first corner frequency of the first high-pass filter, and
responsive to the receiver receiving the pulse or the second reflection of the pulse on the second cable, output a notification of a short between (i) the first cable of the multi-cable communication system and (ii) the second cable of the multi-cable communication system.

9. The apparatus of claim 8 , wherein, responsive to the receiver receiving the pulse or the second reflection of the pulse on the second cable, the processor is configured to:
calculate a time duration between (i) transmitting the pulse on the first cable of the multi-cable communication system and (ii) receiving the pulse or the second reflection of the pulse on the second cable of the multi-cable communication system, and
calculate a distance to the short based on the time duration and the speed of the pulse within the first cable of the multi-cable communication system.

10. The apparatus of claim 9 , wherein the processor is configured to:
calculate a time duration between transmitting the pulse on the first cable and receiving the reflection on the first cable; and
calculate a distance to the first cable end or the fault based on (i) the time duration between (a) transmitting the pulse on the first cable and (b) receiving the first reflection on the first cable, and (ii) a speed of the pulse within the first cable.

11. The apparatus of claim 8 , wherein the multi-cable communication system comprises and Ethernet communication system utilizing four twisted pair cables including the first cable and the second cable.

12. The apparatus of claim 11 , further comprising a hybrid device, wherein:
the transmitter is configured to couple communicatively to the first cable, the second cable, a third cable, and a fourth cable via the hybrid device,
the receiver is configured to couple communicatively to the first cable, the second cable, the third cable, and the fourth cable via the hybrid device, and
the processor is configured to repeat monitoring and outputting for the third cable and the fourth cable in connection with detecting shorts between the first cable and each of the third cable and the fourth cable.

13. The apparatus of claim 12 , the processor is configured to:
cause a respective pulse to be transmitted on each cable in the four twisted pair cables, and
repeat for each cable in the four twisted pair cables monitoring and outputting.

14. The apparatus of claim 8 , wherein the pulse comprises a 100 nanosecond pulse.

15. The apparatus of claim 8 , wherein the processor comprises a digital signal processor.

16. The apparatus of claim 8 , further comprising a memory device coupled to the processor;
wherein the processor is configured to execute machine readable instructions stored in the memory.

17. The apparatus of claim 8 , further comprising a user interface coupled to the processor;
wherein the processor is configured to output the notification to the user interface.

Assignees

• Marvell Int Ltd

Inventors

• Breed Divya Srinivasan
• Mcclellan Brett A

Classifications

• G01R31/58

  Testing of lines, cables or conductors (testing of electric windings G01R31/72) · CPC title

• G01R31/11 Primary

  using pulse reflection methods · CPC title

• G01R31/021

  Physics · mapped topic