@audioengr
Just looking at your oscilloscope plots, I would say you have plenty of triggering issues - this would explain why you get bimodal distributions and distributions that look a mirror image of each other.
You would be much better served by analysis of the final analog output of the DAC - any jitter will show up as distortion of the known digital input signal.
The APx555 by Audio Precision is designed to robustly test for jitter by injecting known signals.
https://youtu.be/2ac1bJih05k
Just looking at your oscilloscope plots, I would say you have plenty of triggering issues - this would explain why you get bimodal distributions and distributions that look a mirror image of each other.
You would be much better served by analysis of the final analog output of the DAC - any jitter will show up as distortion of the known digital input signal.
The APx555 by Audio Precision is designed to robustly test for jitter by injecting known signals.
https://youtu.be/2ac1bJih05k