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VMC sweeps

Question asked by miyamky on Jul 13, 2012
Latest reply on Jul 14, 2012 by Dr_joel
I'm performing a VMC measurement.  Immediately after loading my cal file, the analyzer seems to just sit there before starting a sweep (the port 1 light IS active).  After about 1-1.5 mins, the port 2 light goes active and it starts to sweep.  The problem is that if I read the sweep too soon (before at least one sweep is completed - may be just started but I've waited until after the 1st sweep completed) I get a flat trace (close to zero) for a group delay measurement.  I added in a 2min delay prior to start setting all of my instrument adjustments (like changing the measurement type to group delay from the default, etc.) and I get a good trace.  The trace sweep speed itself is fairly slow (about 15-20 seconds) - don't know if that's the impact.

So is the PNA-X waiting for the load to complete before starting the sweep or is the sweep just that slow (I did notice that if I watch the sweeps, a new sweep doesn't start after one sweep completes - again, it's just sitting there w/ the port 1 light active)?

How do I programmatically know when I can actually read the trace?  TIA  

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