06-13-2018 08:02 PM
Hello All,
The problem is when I checked the measured samples for each measurement I found they are not exactly as I expect. The attached picture shows that I insert a time interval for FOUR measurements each one with 11600 samples but I got a different number of samples for the measurement some of them higher and some of them less than 11600.
I am not sure if there is time resolution limitation! Please if someone has an idea about what is happening I would really appreciate.
06-18-2018 08:54 AM
Hello Thoalfukar,
I will look around a bit and see if I can find anything. Meanwhile:
1) Could you describe your system/setup in its entirety? What other HW, SW etc.
2) 10 000 / 10MHz is 1 ms, not 0.001 micro sec (in case you used this as configuration settings somewhere).
3) What are the units of the axes in the picture you sent?
06-18-2018 11:42 AM
1) Could you describe your system/setup in its entirety? What other HW, SW etc.
I am working on developing measurement system able to perform load-pull measurement and S-parameter of a DUT.
The system is configured by two chassis. One of them includes VSGs and the other one includes the VSAs. The chassis is synchronized by PFI caple and the 10MHz backplane signal. I am using list mode technique for the generation and the acquisition process.
To perform such measurement I set a list of powers and measure the response of the device for each injected power. Because of the list mode setting, the time interval of each power level should be set to receive the required number of samples.
The problem I am facing is the number of samples is not match the time I set, and it is different from power level to another. For example: If I want 10000 samples for each power level at 10MHz sampling rate, the time interval for each power level should be 10000/10MHz = 1 ms, but when I checked the received measured sampled I found they are not exactly 100000, as shown in the previously attached graph, some of them more some of them less for the same time interval.
2) 10000/10MHz is 1 ms, not 0.001 micro sec (in case you used this as configuration settings somewhere).
Yes, sorry Its 1ms
3) What are the units of the axes in the picture you sent?
the X-axis is sample index
the y-axis is recived voltage
Note: in the attached graph the required number of samples is 11600 samples
06-19-2018 05:10 AM
Hi again,
Thanks for the detailed information.
1) Which VSGs and VSAs do you have?
2) Have the measurements in the graph (1-4) been performed with the same VSG/VSA?
06-19-2018 05:18 AM
Hi,
thanks for reply,
the VSG: PXIe 5673E
VSA: PXIe 5663E
YES, actually all these measurement by the same VSA and VSG
06-19-2018 08:58 AM
Hi again,
Thank you.
Would it be possible to post the code that you use?