Generating TTL clock using an ARB

[old_man]

I am trying to set up a TTL clock at 14.33mhz in a test set using a PXI-5421.  I program a 5v squarewave with a 2.5v offset.  It complains about the offset being too large.  I though maybe it was worried about the output voltage swing so I went to 2.5v and a 1.25 offset just to see what happened.  I get the same error.  Apparently you can't take a square wave and make it go from 0v to some arbitrary voltage level (ie, 5v).

I have the output Z set to high.

Is there a way to get this to work?

Message Edited by old_man on 03-21-2006 08:24 PM

[Travis_W]

As per page 3 of the 5421 specs, the maximum DC offset that can be applied is 25% of the output range of the signal.  Creating a 0-5V signal with a standard function is not possible.

Although you cannot accomplish this using a Standard Function, you're in luck that you have an Arbitrary Waveform Generator.  When using arbitrary waveform mode, you can load a waveform that is a 0-5V square wave, and you should be able to generate it with no problem.

Have a great day!

Travis

[old_man]

I ended up building an array with levels of 0 and +1 instead of +1 & -1.  I was able to get it that way.