Please for comparison reasons, repeat the test of noise ground as decribed at post #1330, page 89 and give us the Vp-p value and the capture.
More about:
The "Mainboard" also have a DC/DC connected to ~5.54V it generate noise that goes to the analog power of the input stage. This DC/DC supply power to the entire DAC.
Below the shielding metal sheets of the input stage there is a 5V LDO, connected to ~5.54V (i.e Vdo <0.54). And if Owon did not put any filters (F.Bead) in the input of the analog power for the DAC, less to the input of the analog power for the input stage. This LDO is able to reject only some frequencies <1MHz. Similar for the 7905.
Yes, please for comparison reasons, repeat the test of noise ground as decribed at post #1330, page 89 and give us the Vp-p value and the capture.
More:
- To correct variations between channel 1 and 2 in some oscilloscopes Owon add extra resistors there where Owon think.
- The 5V regulator thermally affects more the channel 1, since it is closer, this explains its greater DC drift.
Now I do not think Owon would like to save money, rather it seems that, did not even know how to make the oscilloscope.
Well done Owon... This is not an oscilloscope, is shit.