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PNA-X Opt-29 IMDX measurement issue

Question asked by rok on Apr 28, 2015
Latest reply on May 6, 2015 by rok
Hello,

Just wanted to alert folks of a potential issue with Opt-29 based with internal dual sources and combiner PNA-X as it relates to the IMDX measurement channel.

I'm using the win7 version with firmware A.10.25.02.

The problem is with the 'Noise Path Configuration' settings. In another thread, I alluded to the fact that when loading older csa files, it would set all the non-noise figure measurement channels 'Port 1 Noise Tuner Switch' setting to either all 'Tuner' or all 'Bypass' mode, doing so in a seemingly indeterminate fashion. For most measurement channels, (i.e. SMC), as long as you calibrate and measure in that same mode, you should still get the same results. However, for the IMDX measurement channel, it seems you will always get the wrong results (i.e. much lower than expected)  if 'Port 1 Noise Tuner Switch' is set to 'Tuner' mode. 

The way to verify this is to create a 'PowerMainIn' trace that shows the power level of the input tones. If it is set to 'Tuner' Mode, the input tones power level from the trace will be lower by roughly 3 to 5 dB vs what is set in the 'Stimulus' setting. 

If Keysight can verify this issue and work to address it (i.e. firmware will not allow any IMDX channel  'Port 1 Noise Tuner Switch' setting the option to choose 'Tuner' mode, or auto-sets to 'Bypass' mode regardless of what is set in the .csa file), that would be great.

Thanks,
rok  

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