Placing the trigger 'dot' on a time waveform

[Coryman]

Bob,

I coded your example into my vi and it's a no go.  The sine wave is fine, the maximum peaks are located fine.  I changed the trigger dots to a larger white dot.  They continuously move up and down vertically inside the graph, without sitting on the sine wave.  In other words, they are at the correct position along the X axis, but their amplitude move from -max to + max of the sine wave, and again, as I have said, not on the wave itself.  I'll recheck the code to make sure I didn't miss something.

[Coryman]

Bob,

I have attached my vi.  When you run it, you only have to put in the Motor Speed of 3600.  You will see the trigger pulse is actually riding the sine wave!  It goes from left to right!

Sorry if the code seems crowded and a mess.  It is an experiment in progress and I will clean it all up once it does what I want.  I have left the overlays of the X and Y time signals.  You can also see the code that 'lights up' the beginning of the filtered orbit with a red dot.  Your code now sits in what I will want, a continuous running scope.

[Bob_Schor · Accepted solution]

Yes -- the reason that the Trigger signal appeared to have its own variation is that it was being place at the "zero phase" point of the sine wave, the place where the slope is the steepest and any effect of noise is magnified, so you were really looking at noise, not signal.

You can also run my Demo and crank the Noise Control on the Front Panel up and down and look at the Green Square behavior ...

Bob Schor

P.S. -- oops, this Reply belongs before the last two of your Posts.  Sorry about that.  I sort of thought that we'd finished this topic, and that your Problem had solved ...

[Coryman]

Now I am really confused.  If the sine wave and the trigger both come from a triggered event, then why wouldn't the trigger dot stay at one time distance?  

[Coryman]

Bob,

I added a trigger to the data and also widened the duty cycle so I would catch all of the triggers.  There is also a 135 degree phase shift on the trigger from the sine waves.  And guess what?