Hantek DSO5202BM: A bug with voltage measurement was detected

Oleg10011001

I have a constant voltage with a small variable component:



With the channel settings can be found in the menu of its settings present on the screen. Next, I want to cut off the constant component of the signal and study only its variable component and for this purpose the parameter Coupling from DC mode is switched to the AC mode. Now see how the measured voltage (pk-pk) changes on the oscilloscope screen for different sweep time:







The main focus is on the screenshot with the installed sweep time: 800us. Look at how the measured voltage (pk-pk) differs in the variable signal component from that which can be seen in other screenshots. All screenshots show a signal shot from one point for different sweep time.

Even during the study of the variable component of this signal, I somehow could not switch the depth of the memory used by the oscilloscope. When I press the F5 button, I hear a confirmation button click (I have the appropriate setting enabled), but at the same time I do not switch the used memory depth, which is evident both in the corresponding setting of Mem Depth and the fact that the oscilloscope does not start to freeze as it Usually when using a large memory depth. No matter how much I press the F5 button, the corresponding settings will remain as shown in the following screenshot:



Still it is not clear why when viewing the variable component of this signal on the screen, synchronization was lost every second, no matter how I set the trigger level... Sometimes synchronization lasts longer sometimes less, but in any case it breaks very often.

P.S: Sorry my bad english.

Oleg10011001

Looks like I found the cause of the wrong voltage measurement. I was personally to blame for not doing the "Self Calibration" procedure. I did not notice that the temperature in the room noticeably changed in this case. The amount of memory used also began to switch normally; Apparently there was just a short-term failure that disappeared after the oscilloscope restart. Sorry for the false alarm.