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Digital Waveform graph with a lot of samples

Hi,
I have to display in a Digital Waveform Graph a lot of data read from a file(2.000.000 of samples for 36 signals). If I read the file and I try to display all the data, the Vi became unusable. For example, to zoom a graph region, it may take 30-40 seconds, scroll is impossible ecc, ecc..
Apparently LV doesn't perform a decimation of points. In measurements studio 8, this problem doesn't exist...but I have to use LV 7.1..
any suggestion ?
At the moment I have developed a DLL in VC++ that perform a decimation of samples, but performance are not very good !
Thank you for any idea.
Regards.
 
 
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Message 1 of 6
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Hi Garraty,

Excuse me but I have several questions for you.

1)     Have you tried some kind of incremental approach, starting from 1 waveform and increasing towards 36? Do you experience some kind of on/off degeneration between, les’s say, 34 and 35 waveforms?

2)     How can you decimate a digital pseudorandom sequence of 2M samples without loosing information?

3)     Is this 2M samples an unavoidable constraint for your application?. Actually, it seems very difficult to extract some kind of visual information from a pseudorandom pattern of this length?

 

Thank you very much.

 

Kind Regards

 

FiloP

 

FiloP
It doesn't matter how beautiful your theory is, it doesn't matter how smart you are. If it doesn't agree with experiment, it's wrong.
Richard P. Feynman
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Hi Garraty,   
I digged a little further. 
It seems that performances of Digital Waveform Graph have been improved in V 8.0.1 with respect to previous ones. 
If LV 7.1 is a constraint I suggest you to avoid loading all data and implement a control that load only small slices of data at a time depending on Zoom Factor and Scroll Position. 
You may tray using shif registrer to have some portion of data immediatly available and load the rest from your file when needed. 
This is the simplest idea that came to me I'm sure you will find better ones!
 
Best Regards
FiloP
It doesn't matter how beautiful your theory is, it doesn't matter how smart you are. If it doesn't agree with experiment, it's wrong.
Richard P. Feynman
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My situation is similar in that I am attempting to display PLD signal outputs into a digital waveform. Any idea where I can find an example where a 16 bit binary string is displayed using the digital waveform? I have been trying for a couple of weeks and no success using Labview 8.0.  Simply looking to relace an external logic analyzer with a LV generated one that can read in and display a 16 bit discrete digital signal.
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Hi,

I suggest you to look at this KB and this forum post.

Hope this helps!

Bye!

 

Licia

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Message 5 of 6
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Labuser123 wrote:
My situation is similar

I also totally agree with all the points of the original poster, esp the (absence of) vertical Scrollbar for Digital Waveform Graphs. You can support me here for this feature. Smiley Happy

 

Maybe you need to look at here and here, particularly for Ben's ideas & suggestions in the second thread, to get started with the Digital Waveform Graph more confidently, that too if you are using LV 8.x.

- Partha ( CLD until Oct 2024 🙂 )
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