why NI digital pattern captured result is different from displays in digital scope

[Onezhenji]

Hi guys,

i found that the captured result is not the same as the result displayed in the Digital Scope.

Here is the digital scope results, it shows that the sequence is b'00000000':

digital scope displays the result is b'00000000'zoomed and aligned

but the results shows in capturewaveform is b'00000010'. Here is the screenshot of CaptureWaveform.digicapture:

i have checked the pins in CaptureWaveform.digicap:

pins setup is right

Hoping someone can help me with this, thanks!

[santo_13]

To the basics of Digital Scope feature of Digital Pattern Editor, it is not a "Scope" rather a interleaved sampling and will work only for repeatable patterns i.e., the the response of the DUT will remain the same when bursting the pattern any number of time with same inputs.

The waveform you see is a effect of points from several hundred bursts whereas the capture waveform stores data from only one burst.

So, if you're sure that the technique described above will not affect your pattern or DUT, please check the VOL, VOH to ensure that digital levels are interpreted correctly.