I'm checking on this - will update ASAP.
-Rich
Thanks.
I'm sure there is some very deliberate technical reason for it, will be interesting to find out.
Hi Dave - here's the response from R&D. As you suspected, there is a deliberate reason for it:
For this matter, the ratio between sampling rate and pixel per div are important. For 50 ns and 100 ns timebase, the result would non-integer numbers for the pixel per div, e.g. 0.63 for 50 ns at 1,25GSa/s. In principle this could be displayed, but it just would not look very good. For 40 ns and 80 ns the pixel per div are integers, so displaying the measurements looks better.
-Rich