[time-nuts] Is there any way to use a TIC to measure time of > reflection on a PCB?

[Grant Hodgson]

Dave

Couple of thoughts here :-

1)  A 'real' TDR measurement would require a pulse generator with a  
fast rise/fall time.  The faster the rise/fall, the better.  A  
directional coupler could be used to separate the forward and  
reflected signals, or you may be able to get away with a 3dB splitter  
and use the forward pulse to start the TIC and the reflected pulse to  
stop it.  However - this will only give you a measurement of the  
propagation time of the pulse - using the VNA with a short at the end  
of the microstrip (as has already been described) would give a much  
better result.

So yes, you could use a TIC, but you would need a pulse generator and  
you wouldn't have a better measurement than that already.  Actually, a  
fast 'scope would be better than a TIC as you would be able to see the  
shape of the reflected pulse, which is somewhat more useful than a  
simple time measurement.

2)  Given that the student doesn't have the TDR option on his VNA, it  
would be possible to simulate this using Matlab, Mathcad or one of the  
other analysis packages which are now freely available.  The formatted  
data (in the frequency domain) from the VNA can be read via GPIB,  
inverse FFT'ed, time-gated and FFT'ed back into the frequency domain.   
Excellent learning task for a keen student.

regards
Grant