Would this circuit work?

[calvingloster]

I am generating a fast pulse in the order of 5ns. This pulse travels down a open ended wire and reflects back. Would i be able to switch the return path of the reflection to use on another trigger circuit? as a rough idea i have come up with this rough circuit. The analog switch select pin is triggered by the pulse but is slightly delayed due to the capacitor used. Im guessing that i would need some more logic like a Schmidt trigger to create a clean fast edge on the select pin but would this concept work to divert the reflection?

[Doctorandus_P]

Voltages are always measured as a differential between two points. That is why your DMM has two wires. If you change the switch position, your loose wire end does not have any sort of reference. Apart from that, the switching itself is going to put it's own signal onto the wire.

The normal way for time domain reflecto metering is to have both the signal generator and the meter connected at all time, and then just figure out a way to ignore the initial pulse. In your case, a comparator that triggers at around 3V should work.

https://en.wikipedia.org/wiki/Time-domain_reflectometer