GW Instek GDS-2000E teardown /short review, comparison with Rigol DS2000(A)

[nctnico]

I think you should first check what the error percentage is of what you are seeing and then compare to the specs. You can expect the DC error of an oscilloscope to be in the ballpark of 1% to 2%. 1% of 5V is 50mV so seeing an offset error of 1 division at 50mV while looking at a 5Vpp signal doesn't seem out of the ordinary to me.

Yes, you're right. That's within specification limit.
I wanted to use this scope to average 8-bit digitized waveforms on a PC so I can effectively see more bits of information. But since (at least for me) the error is so 'large' with this scope, it can't be used for that.

One thing you can do is use a reference and calibrate your oscilloscope against it. If the error remains constant over time and the temperature is kept fairly constant, you should be able to get more accuracy but likely you'll need to recalibrate regulary (before & after doing a series of measurements).

[Krisztián]

'There are small lies, big lies and then there is what is on the screen of your oscilloscope.' - nctnico

Especially true for these low frequency errors mentioned in the last couple posts.