Some kind of an interim report.
Here compared factory original with "noisy GND" issue and same model but modified.
Compare made parallel so that all other things eliminated. Same time, same enviroment EMI noise level.
Both are same version SDS7102 and both powered using same AC source.
Test setting you see in images. Probe is set for 10:1 so that its freq response is full. All tests used same probe and compensation adjusted only with modified oscilloscope. (you can see small difference becouse scope inputs capasitances are not very exactly same)
These test setup is made so easy that everyone can do this same test without any external equipments.
Note memory selection!
Probe hook and probe own long GND wire (both) connected to Probe Compensation output GND.
(If use probe tip directly + very short GND wire connected to GND it do not show this noise becouse there is not GND wire "high" inductance.)
Unmodified
Modified
Probe 10:1 and tip connected to Probe Comp out and probe own long GND wire connected to probe comp out GND.
Note Offset setting! Whole signal level (5V) from peak to peak is 100 div vertically!
Unmodified
Modified.
Work is not ready. Experiments, tests and work for finding best way for (simple) DIY solution is still under work.
Also waiting Owon official version for solve this problem.