Unwanted spectral peaks in PXIe-5601 with PXIe-5622 digitizer and PXIe-5652 LO

[soumendras]

I am using PXIe-5622 with LO PXIe-5652 and PXIe-5622. I notice some unwanted peaks even in some simple applications where I generate single frequency (with attached signal generator and other non PXI based signal generators). I have no idea what's going on. Your help will be highly appreciated. Please see attached pictures

[NJKirchner]

What you're seeing there is, highly likely, IF Images showing up in the lower bands.

Any spectrum/signal analyzer is suspect to out of band images showing up in strange places and they are part of the spec. 

Now, given that they are less than 500MHz away from carrier and fairly large, I would call into question 2 things.
When is the last time the hardware was calibrated, (both analyzer and generator) 
and do you know if the signals are coming from the generator or analyzer.
When you see strange things happen in loopback, you may not know who the culprit is.

-5663

Also, you can refer to your hardware as the "PXIe-5663 and the PXIe-5673" VSA and VSG respectively