how to read a pulse with a width of 3 microseconds clearly useing E-Series DAQ.

[weizbox]

I can currently see the pulse useing some code i found somewhere (link below if you want to look at it) but the problem is the pulse is somehwat rounded, im not getting enough points. With the .VI i ahve below i set number of points to about 1.25 million (cant go higher then 1.3 or it complains). Is there any other methods i cna use in order to get more points so I can see a square pulse at 3 microseconds, or does it seem like I need a new card (hope not).

PS: the VI given is a SubVI so the interface isnt the best 🙂

Thanks
-Mark

[chutla]

Since the sample rate of the E-series boards is 200KS/s, you are bumping up against the Nyquist sampling criterion with a 3 microsecond pulse. In fact, to reproduce a square wave reasonably well, you need to be able to sample up to the fifth harmonic of the fundamental "frequency", which is DEFINITELY not going to happen with your hardware. I hate to be the bearer of bad news, but alas, I believe a faster card is called for.

Eric

[JB]

Why not using a counter ? The clock frequency (20 MHz) of the internal timebase would be more then enough to measure the length of the pulse.

See attached example that ships with LV.

[weizbox]

I seem to be missing some of the subVIs, if you could mkae a llb out of it with everyhting in it, i would appreciate it 🙂 thanks

[weizbox]

What sample rate would I need in order to see somthing possibly as low as a 2 microsecond pulse clearly? or mabye even one? (not too firmiliar with all this stuff yet, mainly just got into the programming side of it)

Thanks
-Mark

[JB]

The missing vis are probably part of the new counter palette. I recommend you to download and install it.

Anyway, here is the LLB.