How do I get a 5 MHz plot from a spectrum analyzer to a VI?

[ImpInTraining]

I'm attempting to get the spectrum plot data from a Rohde & Schwarz FSU26 Spectrum Analyzer (with no lack of bells and whistles) in order to display a 5 MHz window display that covers two injected tones at 1MHz apart, and the two products of those tones.  I'm having a little bit of a problem determining what I need to do to obtain the plot from the spectrum analyzer (it comes with hundreds of different drivers for a multitude of purposes), and more importantly, I'm not sure what to do with that data once I get it.  The Waveform chart / graph both have one input, but clearly I need two, don't I?  One for amplitude, and the other for frequency.  Should I use the XY graph?  And is there some simple example of how this has been done using a different spectrum analyzer that I could use to get an idea of how to tie it all together?

[juergenstraub]

Hi,

did you try the Read Trace Example to get started: http://www2.rohde-schwarz.com/file/rsspecan_lv82_read_trace_example_1_1_1.zip

This is available at the R&S driver download site for the FSU: http://www.rohde-schwarz.com/driver/FSULabVIEW.html

BR juergen

[ImpInTraining]

Thanks, I'll check it out.

[ImpInTraining]

The problem with that example is 1) it does not display the frequency across the bottom, and 2) it doesn't have the spectrum going all the way across the screen.  So although it does show a nice example of what you're seeing on the spectrum analyzer trace, it's virtually useless.

[juergenstraub]

I'm sorry that this is not meeting your requirements. The example is supposed to be an small routine to get started with fetching traces from the instrument. Unfortunately, the markup is not in the focus of this. For more in-depth support I'd recommend you to contact you local sales, or the R&S customer support.

[ImpInTraining]

Yeah, believe me... I am.  I'm trying several different avenues.  I need something that will take my X-plot data and insert the frequencies along the bottom of the graph to use in conjunction with the Y-plot data.  And hopefully that way not only will it look more professional, but it might actually extend the whole way across the graph.  Seriously... what causes the trace to stop 4/5s of the way across?  How could someone even submit that as a finished product and feel proud about it?

I'm even trying the online support (via email) but findinig is not the most expedient group.  I get one more step closer to the answer each day because that's how long it takes them to respond to my responses.  I was hoping someone on here had used LabVIEW to create a virtual instrument that would actually show frequency across the graph.  I'm sure it's been done.  I've seen it done on one example (Help>>FindExamples>>Hardware Input and Output>>Modular Instruments>>NI-RFSA>>Spectrum Acquisition>>RFSA Frequency Sweep.vi), only it is looking for a cluster of 3, where I only have 2 to input.  

Anyway, been through a bunch of different NI classes for LabVIEW, and none of them really went into any detail on how to effect the X-Axis on these graphs and plots so well.  One did have us adjusting the input frequency so as to make the sinewave larger and smaller, but it was a real-time oscilascope reading and didn't really have the X-band labelled either come to think about it.  Got me looking for a LabVIEW for Dummies book.

[Lea_D]

Hi ImpInTraining,

I see you're having some trouble with the plotting of your spectrum analyzer in LabVIEW. After reading the above information, I do agree with juergenstraub about getting more in-depth support from the R&S customer support since the driver you are using is from them. 

I have some questions for you and some things to try. First of all, for reference, what LabVIEW version and OS are you using? Do you know the actual driver that you're using? Also, do you have a vi set-up, or are you just going from this example. If you're actually using a specific VI, uploading that to this forum would be helpful.

To display more than one trace at a time, you can always bundle the two traces together using the "Bundle" function and then you can create an output cluster. From this point, you can replace the output cluster on the front panel by rightclicking on it and choosing replace>>waveform graph. This can also be used to replace arrays and numbers with waveform graphs. 

Hope this helps,

[Dennis_Knutson]

When you move your mouse over the graph on the block diagram, you are shown one way to format the data in order to set the x axis to display frequency. The x0 is your starting frequency and dx is the frequency increment. The two values may be something you can read from the instrument. Another method to display your x axis is with an XY Graph. You may be able to read the frequency array from the instrument. I have no idea which options are available with that instrument. It is something for which you will have to study the manual.

[IanTheGood]

Dear juergenstraub,

Three years ago, you posted the comment below which includes a link to a zip file containing an example of a reading a trace from a spectrum analyzer. I tried to open the vi, but there are many sub-vis that I did not have and were not in the zip file. Where am I suppose to get those files? Is there something I am missing. Please assist.

Thank you, 

Ian

[Dennis_Knutson]

Did you download the entire driver from the site above?