Data delay PXIe-6363

[ster]

Is it possible to change when the PXIe-6363 samples (aka strobes) digital data?  I am sampling a digital system that has significant skew (think: triangle wave) and I'd like to delay the data sample slightly so that it captures it at a higher point.  I know the HSDIO is capable of this, but I am curious what options the PXIe-6363 has in this regard.

Thanks!

Gary

[Anthony_F]

Hello ster,

I'm not sure we have enough information to really get to the bottom of your problem but I can make a few suggestions none-the-less.

I think you really are talking about the slew rate of the signal being fairly high, as opposed to skew which is usually a time difference.

If you are just looking for a change on the line you could use change detection

If possible you could insert an opamp and double the voltage (non-inverting opamp with gain of 2).  This would decrease the rise and fall times and introduce some clipping, which could give you a little more time to read the waveform.

Could you give us a little more information about this setup?  Whats generating the slewing digital signal?

[ster]

Slew rate.  I don't have the ability the manipulate the incoming signal, but would like to delay when it is samples.  I'm using a PXIe-6363 DAQ.  What sort of data delay options do I have?  Basically, I'd like to sample a small (but finite) amount of time after the leading edge.  Speeds are in the 5-10MHz range if that makes a difference.

Thanks,

[John_P1]

Hi Gary,

The sample clock is derived from the internal 100 MHz timebase.  There is a Start.Delay property which can be set in terms of timebase ticks or in terms of seconds.  So, in theory you could tweak when the first sample occurs in 10 ns increments.  The minimum value is 20 ns (i.e. you actually can't have a delay of "0").

However, this delay has to occur relative to a start trigger.  So, you would need to have a TTL signal with a sharp rise time that is in synch with the triangle wave that you can use as a start trigger.

Best Regards,