On Sun, Oct 28, 2018 at 8:31 PM Hal Murray <hmur...@megapathdsl.net> wrote:
> > drkir...@kirkbymicrowave.co.uk said: > > I'm feeding a sine wave from a Stanford Research DS345 30 MHz function > > Are the levels set so it triggers at the same point? It doesn't look like > it > in your photo. > > Looks like you are running at 1 MHz. If the stop trigger is a little > lower/earlier than the start trigger, you will have to wait a whole cycle, > so > 950 ns is a reasonable result. > Looked like the levels were on Preset. So, a little difference in what "Preset" means and as Hal says, you wait a whole cycle. One could fiddle with the stop trigger level, but the rise time of the sine at these frequencies is so long, that a small change in the trigger level is going to make a large change in the measurement. I'd try the same experiment with a square wave instead to minimize this effect. Once you get a stable measurement with a square wave, then experiment with the trigger level controls. Going clockwise from Preset, I usually see no trigger, followed by a narrow band where it triggers, followed by no trigger. In the band where it triggers, assuming adjusting a stop trigger that is set to the rising edge, as the trigger level is increased, so does the time interval. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
