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Simultaneous capturing pn data-values and spurs

Question asked by agaurav on Feb 24, 2011
Latest reply on Feb 7, 2012 by agaurav

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Hi,
I am having some trouble sending GPIB commands successfully to E502B. (I could successfully reset it but when I try to grab data etc., I am having some trouble. Need to learn a bit more before I can ask specific questions here)
Meanwhile I am trying to dump out phase noise and spurs using the GUI.
I am using segment phase noise as well as phase noise but I have the same trouble in both. How to capture spurs and phase noise data value at the same time instant.
Since I am using GUI, there is a significant lag in time in capturing phase noise using 'save-save data trace' and then pressing 'Trace-spurs-spurious list' . As a result, during post-processing of results, I see that I get peaks in phase noise where there is no data in spurious list and I get spur in spurious list where there is no peak in phase noise. I agree that this issue only arises when you have got moving spurs, but if your DUT is as it is, how to resolve this problem, can anybody help me.
Thanks and Regards,
Anand

FYI, I am using averge number of 16 and correlation number 32

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andyowen Feb 24, 2011 11:06 AM
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I recommend that you turn off the continuous trigger (Trigger > Hold once you have acquired your data). The trace data will be static and you can retrieve the trace then spurious list.

If you are using averaging, turn on Average Trigger in the Trigger menu. When you press Single, it will acquire 16 averages (regardless of how many correlations) then go into Hold mode. Again, grab your data after it goes to hold.
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agaurav Feb 25, 2011 8:13 AM
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Hi Andy,
Thanks a lot for your reply.
Meanwhile, I could make a script that stores phase noise across different segments at different RBWs for more resolution.
But, I am having trouble in automating it.
I am using
STATus:OPERation:CONDition?
to detect the condition so that I can detect when the segment phase noise measurement is complete (in GUI terms, the 'single' measurement moving to 'hold', on completion). Seems, this is not the correct register I should read. Could you please help me with which bit/register to read for this purpose.
Also, I am trying to save the data and spurious list but where in memory is it saving, I couldn't find the output file.
I am using the following command for saving the data
MMEMory:PS1:TRACe1:STORe file.1.csv
and the following for saving the spurs list
CALCulate:PS1:TRACe1:SLISt?

Thanks for your help.
Anand
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andyowen Feb 25, 2011 11:27 AM
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I don't know what the default directory is. I would suggest using the absolute path to where you want it. For example:

MMEM:PS:TRAC:STOR:DATA "C:/Temp/file1.csv"

Be aware that :CALCulate:PS:TRACe:SPURious:SLISt? does not save the spur table to file; it simply returns the spur list to your program as an array. If you want to save it, use :MMEMory:PS:TRACe:STORe:SPURious:OSSPur:FLISt "C:/Temp/file2.csv"

That should be the right register, specifically bit 4 (equals "1" during measurement). When I query it, I get "16" while the measurement is running and "0" when it's done. Is that not what you read?
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agaurav Feb 28, 2011 4:33 AM
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Thanks Andy,
Yes, I could now save things to file. But spur still remains to be dumped into a file.
The command you suggested does write a file but that file doesn't contain anything other than 0 despite the fact that there are spurs I can see and also, when I click in the GUI, on 'Spurious List', I get a list of spurs.
Can you suggest something?

Regards,
Anand
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agaurav Feb 28, 2011 4:57 AM
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I must mention that I am trying to find power of spurs and set it using the command
CALCulate:PS1:TRACe1:SPURious:POWer ON
Is it that I get empty file because OSS in the command MMEMory:PS1:TRACe1:STORe:SPURious:OSSPur:FLISt
means Omit all spurs as I dont have any table for omit specified spurs and I dont want to omit any.
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agaurav Mar 8, 2011 8:34 AM
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Hi,
I could succesfully do all the measurements with segment phasenoise and also dumping out the spur values into a file. But, just today I got the E5052B with the jitter measurement software installed on it. I am surprised that this kit doesn't contain Segement Phase Noise feature. Is it so that only one of the two - Segment Phase Noise or Jitter measurement software - is available in E5052B or is it that the company I am renting the instrument from sent me one which has the software for jitter measurement installed but segment phase noise measurement feature not installed.
Please let me know so that I can contact them and ask for the Segment PN measurement installed.
Another question I have is, how can I dump out the measured jitter value out into a file using remote programming.
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RayH Mar 8, 2011 9:28 AM
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Check the firmware version on the rented E5052B:
System, Product Information

Segment Phase Noise requires FW version A.03.20 or above.
You can update the firmware yourself. See the information at this website

E5052B Signal Source Analyzer Firmware Update

The latest version is A.03.22
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agaurav Mar 9, 2011 1:36 AM
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Hi Ray
Thanks for your inputs. I'll check that today.
Could you please help me with the way to capture jitter results using GPIB commands.
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agaurav Mar 9, 2011 2:03 AM
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Another important thing, if I update the firmware, will the Jitter Evaluation Kit still work or will it be erased?
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RayH Mar 9, 2011 8:00 AM
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The jitter functions in the SSA-J jitter application (Macro Setup, Application, Jitter) are not programmable.

If you just do a simple phase noise trace integration (Marker Function, Analysis Type, Integration) then
:CALCulate:PN[1-1]:TRACe[1-1]:FUNCtion:INTegral:DATA?
will return the calculated jitter.

The SSA-J jitter application will not be affected by the firmware update.
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agaurav Mar 10, 2011 3:26 AM
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Hi Ray,
Thanks a lot for your invaluable information. it solves my problems.
I want to measure jitter based on phase noise power lying between 12 Khz and 70 Khz. The options for Stop frequencies > 10 Mhz, in phase noise measurement is 40 Mhz, or 100 Mhz. My carrier is at 150 MHz. Is there anyway I can change the stop frequency to 70 Mhz, instead of 40 Mhz so that the jitter is calculated based on power between the freuqncy of my interest. Presently I am using start frequency of 1 Khz and stop frequency of 40 Mhz and calculating the jitter between 12 Khz and 40 Mhz by placing the the x-markers at those points. Is there a way to extend it. I can't choose 100 Mhz for obvious reasons that my carrier is less than 200 Mhz.

I must say that this forum, I discovered just a few days back, is extremely helpful. Thanks to you folks for that.
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RayH Mar 10, 2011 1:12 PM
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sorry -- the maximum offset frequency is controlled by the frequency band. For a 150MHz carrier, you must be in the 99MHz-1.5GHz band. This limits you to 40MHz, as you already know.

This is from the Help file:
         Sweep stop values that are selectable differ depending on the selection of the carrier frequency band.
              *
                  For 10 M - 41 MHz
                  100 kHz, 1 MHz, 5 MHz
                *
                  For 39 M -101 MHz
                  100 kHz, 1 MHz, 5 MHz, 10 MHz, 20 MHz
                *
                  For 99M - 1.5GHz
                 100 kHz, 1MHz, 5MHz, 10MHz, 20MHz, 40MHz
                *
                  For frequency bands other than above
                  100 kHz, 1 MHz, 5 MHz, 10 MHz, 20 MHz, 40 MHz, 100MHz

Sorry, but I do not have a way to work around this.
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agaurav Feb 7, 2012 3:35 AM
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Hi,
I find a big difference in jitter calculation from phase noise data and the jitter which SSA returns when I use phase noise trace integration.
The phase noise data I grab is with Average of 4 datas with correlation=4. But, the phase noise trace integration, I observed, seems measurement based on every single plot. So, does it mean my jitter calculation is more accurate? I am getting a huge difference in the values and hence this question. When I cacluate in matlab, from the phase noise plot, I get jitter = X ps and the phase noise trace integration of SSA gives 1.4X ps as jitter value in the same band. I also have SSA-J jitter application which returns similar value as SSA phase noise trace integration.
Which is most accurate way of measurement?
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Simultaneous capturing pn data-values and spurs

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