Some seem to think AC coupling is just a simple first order high-pass (RC) filter at the scope input, which might be true for simple low-bandwidth designs only. ......
Hello Performa01!
First of all, let me use this opportunity to thank you for your kind sharing of your knowledge. You have a talent of clarity in expression, explain things well and are very professional in both method of approaching problem and in presentation. Your work on testing Siglent scope is superb.. It serves as both a excellent source of information about scope in question, and also about scope theory and use in general and shows method how to do things right...
That being out of the way, I would like to also thank you for this excellent post. It stands in full, and explains some things well..
But I, for one, am aware that scope input path (together with probe and circuit under test) is anything but simple...
It might as well be that something very similar to what you explain is at work here...
My problem with it is that it is almost 10% error, at 50 Hz.. Right there where you would measure if you are looking into linear power supplies or audio......
And it is on a scope that costs 3x more than Rigol Z-box or 2x than Siglent ... That don't have such issues as far as we know...
Which would be OK if 1000x manufacturer's condescending slogan wasn't, and I quote : "Scrap the toys, get a real oscilloscope. Have confidence in your measurements with ............."
I have enormous respect for HP/Agilent/Keysight. I grew up with them being standard of highest quality and corporate ethics all should aspire to.
But at his moment, I honestly believe that not buying Rigol 2000A or Siglent scope for the money they ask for 1000X would be just bad choice.
Only thing that would work for 1000X series would be that their slogan was true.. Which at this point is not so clear..
I hope Keysight will live up to their reputation, and investigate this. If there is an issue, for all affected it should be fixed in warranty..
They paid more money than they would to other manufacturers, because of reputation and expecting better support ..
And if I had to take a wager, i would think the Keysight will sort this out...
Thank you and best regards,
Sinisa