imagine if Rigol enforce "proper design" according to our friend's definition, that requires probing at 1MSps need to cutoff analog BW to 500kHz, that will be a total screw up imho.
I presume this was addressed to me. This is again you saying something completely invented and then blatantly lie I said that..
I will repeat again what I said:
While any scope can be made to undersample by user driving it wrong/ without proper knowledge, there is no 4 ch + MSO scope out there (including Hanteks and Owon and UNI-T) that will try to sell you 200Mhz scope that samples at maximum of 156.25 MS/s when all channels are on.
My problem is not that DHO900 will
sometimes undersample
(like the rest of the scopes). Problem is that
unless you use it like you have bought 2 ch scope,
it CANNOT satisfy Nyquist at any setting of memory and time base.
That is either bad design (which it cannot be because Rigol does know better) or deliberate, very unsavoury, marketing scam.
You know ones that tell you something with big letters on first page, followed by 3 pages of disclaimers explaining how it applies in only certain special cases...
EDIT: This undersampling problem does not apply to DHO800 in it's factory form 100 MHz. They did that one right as far as sampling goes. It is still a bit marginal with more than 150MHz front end BW, but that is probably OK. It should work OK. Except short memory in 4ch mode that will also drop sampling rate very quickly as you go longer timebases.