Hi,
I am newly user of PNA N5242B and I use 85052D calibration kits to do the calibration.
However, when I finished the calibration wizard (Smart Cal), the signal just went wrong.
For example, the S21 of the thru was not a line but randomly like noise.
The screen did show from the NO COR to C 2port.
Can somebody tell me what happened ?
Thanks.
hard to say without a picture of the S21 trace. is it possible that you might have autoscaled the S21 trace after calibration? at very small scales, even the most flat response will look like random noise. the next diagnostic step is to turn the correction off and see if the measurement improves with correction off. if it does, that means something went wrong during the calibration (like possibly using the wrong standard in one of the steps or having a loose connector or cable during the cal).
Hi Daras,
Thanks for reply.
I think it is not from the scale because it covers the whole smith chart.
Yes, it does look normal when I turned correction off. But I am sure I did not use wrong standard because I got the same result even when I used ISS with probe
Is there any PNA setting wrong ?
Thanks.
When you eliminate the obvious, then you have to look at the details. You'll have to document all the steps you are taking for the cal in order for us to be able to point to something that could be the cause. You say that the S21 is not looking right, but what about the S11 or S22. if you disconnect the thru and reconnect the open, short or the load to port 1, do you see the proper response from S11 (or S22 on port 2)? What is the frequency range, power level and IF Bandwidth of your channel?
Hi Daras,
Thanks.
After digging deep, I found something unusual. When I used port1 or port3 with port2 to do the calibration, it turned out to be bad. But when I used port4 vs. port2, the calibration result was OK. It was quite strange, so I disconnected all the cables and connectors, and I left port1, port2, por3 and port4 unconnected. I think this should be close to the open case.
So, yes, S22 ans S44 were close to 0dB. But S11 was very small, like -50dB, and S33 was noise like that jumped between +20dB/-30dB.
This suggests that there may be something wrong with your PNA-X receivers on port 1 and port 3. there is a diagnostic display that usually helps in spotting issues with the receivers. you can find it under System->Service->Diagnostics->Receiver Display:
with everything disconnected from the test ports, run this test and you should see a display that looks like this one below. All the reference and test receivers should be shown and have a response that should be approximately equal to the preset input power (in my case it is about -5 dBm). if you are getting something drastically different, than this response, then you may want to consider running the "Operator's Check" verification test (also under the service menu). If that verification fails, then I would suggest you call the Keysight contact center (800-829-4444) or get in touch with your local Keysight rep.
Hi Daras,
Yes, that's quite different for my port1 and port3.
Thanks.
This suggests that there may be something wrong with your PNA-X receivers on port 1 and port 3. there is a diagnostic display that usually helps in spotting issues with the receivers. you can find it under System->Service->Diagnostics->Receiver Display:
with everything disconnected from the test ports, run this test and you should see a display that looks like this one below. All the reference and test receivers should be shown and have a response that should be approximately equal to the preset input power (in my case it is about -5 dBm). if you are getting something drastically different, than this response, then you may want to consider running the "Operator's Check" verification test (also under the service menu). If that verification fails, then I would suggest you call the Keysight contact center (800-829-4444) or get in touch with your local Keysight rep.