开云体育

On Tue, May 22, 2018 at 05:58 am, lop pol wrote:

I think he was referring to to video siggi linked. Which indeed does tell you
to adjust the VAR gain control to fit the rise time markers.

Thanks lop pol for correcting me. I didn't think about the link to the video.
It's not one of Alan's best videos I have to say: You can see the edge shape change (causing rise time to change with it) when he uses the variable attenuation which he just ignores, he ignores the fact that the 100 % level isn't set correctly when he uses the cursors and the 10% and 90 % markings on the 2467B and he ignores the (waveforms/second) duty-cycle reduction by using the B-trace, which of course only has the repetition rate of the A-trace. Does the resulting loss of brightness compensate for the lower intensity at the start of the A-trace because of limited unblanking speed? From my experience, scopes like the 485 don't benefit from using the delayed (B-)trace for this. Maybe other or slower 'scopes do.

Raymond