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NFX Measurement using PNAX

Question asked by cwhoh on Jun 10, 2013
Latest reply on Jun 10, 2013 by Dr_joel
Hi,I'm measuring noise figure of a passive mixer using PNA-X (Firmware: A.09.85.05 with 029 and 083 options). LO=15dBm using external source of ESG. Theoretically noise figure should equal to conversion loss of ~6dB. SC21 looks fine in the same measurement window. However i found >15dB/unstable noise figure with errors of *compression in noise receiver: excess signal* and *compression in noise receiver: gain has been limited*. 

I tried methods below but the errors remain:
1. I realized the errors are caused by the gain settings thus i tried with all 3 (High,Medium,Low) options
2. Change from noise receiver to NA receiver
3. Vector Noise to Scalar Noise Measurement

Please advise is there anything i can do to improve the measurement accuracy. Thanks for your support.