I am investigating the use of SA mode on the PNA-X to replace the PXA we usually use. We do Amplitude linearity measurements using 2 tones and in the past I have utilized the IM Spectrum mode to deliver the corrected and balanced two tones required, however, due to the required speed and carrier to noise requirements I have been forced to use a PXA to perform the measurements.
I thought SA Mode would be an ideal way to return to using just a PNA-X for this measurement, however I am struggling to use 2 tones with de-embedding and power compensation in SA mode. The de-embedding function only adjusts the source 1 tone, the src2 tone remains fixed.
I am doing this with back to back cables for development/investigation. In use this will be required to for embedded LO mixer testing eventually. Which until using it I thought SA Mode would work.
Here is some screen shots of the PNA-X
Without power compensation
With power compensation ON
I think that this may be associated with this here
So searched the help file and I thought this may be the issue, it is not combining in the 2nd tone during the CalAll process
I changed this setting to match like this as per the help file
Re calibrated and it made no difference. I have tried the Source power cal function but cant find a way to save the source power cal and combine it into the normal cal so I can recall it in the measurement.
So, my question is this an expected feature of SA mode? I think the tone remain balanced in IM spectrum (and converters) applications because it uses the source CW centre frequency to set the offset level where as the SA mode uses completely independent source settings.
An extra comment is that after all this I tried setting up a IMX Spectrum Channel to see if I could get that working (super slow sweep time and not enough signal to noise performance compared to SA mode) when I tried to apply the power compensation in the fixturing menu it crashes the firmware.
Can any one help?