Help w/ Eye Diagrams and Mask Tests

[Arsenic]

I could use some experienced help here 🙂

So i have a scope capture of a representative signal that will be used in this VI.

I have several problems which i could use some help with.

1) Trying to create an EYE diagram out of this waveform.  Because it is repeating i have already have the algorithm to chop it up into seperate 'waveforms', how would i go about displaying something like this as an eye diagram with the LV graphs?  I have tried everything i can think of, i cant just use build waveform or hardwire anything because the # of Voltage arrays will differ every time in real usage.

What i did is create a waveform chart, i build a waveform type w/ dt and the Y values and plug it in.  I was hoping to use the 'scope' setup as from the description in help seemed to do what i wanted, but it does not seem like it overlays onto the graph.

Basically i need a way to create a multiplot graph from X,Y coordinates and dynamically increment the number of plots until its done. Hopefully that makes sense.

2) Eventually i also need to do a multi part mask test on this 'infinite persistence' signal if you were.  This shouldnt be too hard as i will have the arrays of voltage at my disposal from above that i can loop through.  My question regarding Mask tests is this, for this particular mask test there are 4 actual masks.  An upper & lower and 2 'eyes' that it must clear, it seems LV's express mask testing only lets you do a top/bottom mask.

What would be the best way to do mask tests like this?  Use the express VI and split it into 2 parts and 'and' them together?  Or would doing it more manually with some of the non express mask stuff prove to be easier?

I got many more questions but i'll stick with that for now 🙂  Thanks in advance!

[Evan]

I would be happy to help you, though I may need some of your code to show you how I did it.  I am trying to track down the code i used for an eye diagram VI.

Basically for graphing it I would suggest an intensity graph.  It leads to really nice graphs that have the persistance.  The challenge is deciding how to scale the intensity ranges.  I did not use an XY because you get a lot of overlaid plots, but not the intensity of how often a value was hit.

I imagine you will need to write some custom mask code, but yo-u may be able to see hwo teh express blocks did the test to get some good idea.  Attach what you have and we can go from there.

[Arsenic]

Yea any help you can give would help..

[Arsenic]

I am really confused when it comes to Intensity charts/graphs, it doesnt seem to want to actually graph the x,y coordinates that i put in..can it be used for that(Similiar to infinite persistence on a newer scope).

[Evan]

Take a look at this example.  You can see where I am creating the waveforms you would obviously use your files there.

[Arsenic]

Doh im still working in 7.1..is there any way you can downgrade it for me to take a looksy?

[Arsenic]

Hmmm well hopefully you read this thread again because i cant open those files and i have a feeling they could help alot..

We do own 8.2 but our current SW is 7.1 so i dont want to upgrade and cause possible conflicts...

[Evan]

Here they are... Note that in the SubVI I use an interpolate 1d that is available in 8.0.  I do that to stretch the points out some.

I would also suggest taking a look at http://forums.ni.com/ni/board/message?board.id=170&message.id=183506&requireLogin=False

[Arsenic]

Well that sort of helps, atleast in learning how the intensity graphing works.

The biggest hurdle i have is making a signal 'loop' over itself.

So i have this long aquisition in X,Y coordinates in a txt file.  It is a long sequence of semi random data.  What i need to do is chop that data up into 115ns portions, and stack those on top of eachother.  The problem is i am not sure what the best method to do this is, because the number of sections that get created from this chop up probably wont always be the same.

[Evan]

Go ahead and attach any code you have already started working with and an example txt file.  We cna then look at that.