Digital canals with timing offset

[flbauer]

When recording square signals with Analog and Digital canals I observe a constant distance between the edges. This distance is in all time resolutions the same number of pixels.

Firmware version rev. 134664233
Git hash 3ef4bf4
Jul 31 2013 22:42:53

[flbauer]

I installed the firmware: 134664313
Git hash 605f1e2
Apr 1 2016

To demonstrate the effect I made screenshots of measurements of the same signal with analog CH2 and digital canal CH3:

[flbauer]

3 more observations:

1. the distance is constant until Timebase 50us.
   From Timebase 20us on the distance begins to change

2. at Timebase 5us the distance is 0 (correct)

3. from Timebases <5us the distance is approx. 1.5 us

Could this be an effect introduced with the timing update we made several years ago?

[flbauer]

Could this be source of the problem?
It seems that the constant offset appears if no resampling takes place when Time correction value is 1024 (except 5us where the offset is 0)

[flbauer]

If I use BIOS::ADC::GetAt(nIndex-4>0 ? nIndex-4 : 0 ) in GraphOsc.cpp for the digital canals CH3 and CH4 the offset is vanishing for the slow channels.