Hacking the Rigol DHO800/900 Scope

[Fungus]

We don't know if it's a bug or a curiosity yet.

Getting the answer to that question is exactly why I suggested that other DHO800 owners check whether it's a systematic issue. I was not interested in a "mine is better than yours" competition -- although I am pleased enough with the result now that you asked for it.

Ok, I just hooked all four probes up to a crocodile clip coming out of my pulse generator, and... nada.

All traces line up perfectly on the rising edge.



Test setup:

[ebastler]

Ok, I just hooked all four probes up to a crocodile clip coming out of my pulse generator, and... nada.
All traces line up perfectly on the rising edge.

Thanks for checking. But with all four channels enabled (and prior to any skew adjustments), all channels were well-aligned for Slavius too. Could you please retry with only CH1 and CH2 enabled?

[shapirus]

Could you please retry with only CH1 and CH2 enabled?

Ideally, every possible combination of more than 1 enabled channels.

[Slavius]

That’s right, this is most likely a firmware bug or a flaw in the Rigol DHO800-900 series!

I carried out the same test measurements on the Rigol DS1054Z and the maximum phase deviation, regardless of whether 2, 3 or 4 channels were included, was about 1.2 degrees on the test signal - Sine 70 MHz.

Here is the phase shift of the signals when two channels are turned on:


And here is the phase shift of the signals when all four channels are turned on:

[mrisco]

New 0.3.3 version
Added "x log" button which allows toggle the X axis between linear and logarithmic scale
Added Y value to the peak annotation
https://github.com/mriscoc/RIGOL_DHO800_DHO900_GUI/releases/latest

[Slavius]

Who knows which calibration point is responsible for what?


And why doesn't the "ADC Phase" calibration work?

It seems to me that this is precisely the “ADC Phase” calibration, with the help of which the phase shift of the channels is calibrated.

Who knows how to calibrate this item? If you select this item, the calibration ends with an error (Failed)