5122 and scope show video signal in bad resolution

Question

i'm using the 5122 digitizer trying to show a nice clear scope (ni scope front panel) image of an entire video frame (all lines).  some of my settings are 2.0ms/div, 50.0 MS/s; TV trigger; a record length of 1,000,000.
what i see on the scope is far from a million points plotted.  where the points are concentrated it is just solid white.  I know the scope is recorded a million points because i've exported the data and analyzed elsewhere but the issue isn't data analysis, the people i'm working on this for need to be able to view the scope image and determine whether it is a good signal (by eye).
if there are any alternate methods to do this then please elaborate. thanks
Jeff Padham
HBE
[email protected]

Answer 1

You are being limited by the resolution of your monitor.  A nice monitor has about 2000 pixels of horizontal resolution.  If you expanded the NI-SCOPE Soft Front Panel to be the full width of such a monitor, you would get a plot area about 1700 pixels wide.  You are collecting 1 million points.  There is almost three orders of magnitude difference between these two numbers.  The soft front panel is doing the best it can.  Unfortunately, it does not support zoom, which would help with this issue.  You have several options:
Take ten or twenty lines of data at once and cycle through the frame, using the Line Number event and changing the Line # to change your position in the frame.  This will only work if your signal is repetitive.  This essentially does what a zoom would do.
Set up your computer with multiple monitors and stretch the soft front panel window across all of them to give yourself more horizontal resolution.  Two monitors is probably fairly easy, since most modern video cards support that many.  More than that can get expensive, since it will require another video card and probably a new motherboard to support an extra video card (although Matrox has a nice external solution, as well).  I am not sure this will give you enough resolution.
Export the data to NI-HWS and create a viewer to zoom and view all of it at high resolution.  This is fairly easy in LabVIEW.  Let us know if want to pursue this and we can give you some pointers (see the tutorial Managing Large Data Sets in LabVIEW, which has an example which almost does what you need - you would need to add the file I/O to replace the waveform generate code).
Write your own application in LabVIEW to take a frame and allow zoom on the final result.  Once again, this is fairly easy in LabVIEW.  The NI-SCOPE examples and the previously mentioned tutorial should give you the info you need.
Let us know if you need more help.
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