Teledyne LeCroy QPHY-DDR4 - Manual (Page 18)

Once everything is properly set up the oscilloscope display should look similar to the figure below. If there
was no propagation delay due to the probe, and no internal oscilloscope channel propagation delay, the
50% trigger level would be in the middle of the oscilloscope grid.
The channel’s deskew value shall be adjusted so that the 50% rising edge point is centered in time, as
shown below. From the channel setup dialog, enable Sinx/x interpolation and set the averaging to 50
sweeps. To adjust the deskew value, touch the Deskew entry once to highlight it yellow, then use the
Adjust control knob to modify the value. Starting with a timebase of approximately 10 ns/div, adjust the
deskew value to move the rising edge of the trace to the center of the display. Now, decrease the
timebase to around 20 ps/div and adjust the deskew value so that the 50% rising edge point is centered in
time. This process shall be repeated for each probe using the same probe tip.
When QualiPHY is started the deskew values from each channel dialog are saved and stored by QPHY at
the beginning of each run. However, at the end of the testing these values will be erased. By saving a
panel setup it is possible to refer to the deskew values after testing has completed.
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