How to measure the length of network cable

Thread Starter

speed1

Joined Mar 9, 2012
16
Hi all,
wishing you nice weekend :D
I have a project to do a network cable tester, I need to add a function of measuring the length of the network cable how to do that.
please if you have any idea please share it we may get benefit.
thank you
 

n1ist

Joined Mar 8, 2009
189
Look up Time Domain Reflectometry or TDR. Basically, send a pulse down the cable and time how long it takes for the reflection from the far end to come back.
/mike
 

vpoko

Joined Jan 5, 2012
267
I don't want to hijack this thread, but I'm curious about TDR. How would you measure the echo with enough time precision to get an accurate reading? With the speed of light being about 300 million meters per second, would you need a device capable of sampling at 300 MHz to be able to get accuracy to within a meter, or are there other tricks that can be used to enable slower devices to take this measurement?

Edit: Never mind, I looked it up and it appears it's not just measuring return time (reflection magnitude, shape, and duration are involved, at least according to the Wikipedia article).
 

Thread Starter

speed1

Joined Mar 9, 2012
16
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