Random trigger mode
I am confused about this feature of the 7T11, because it further needs a periodic signal to synchronice and predict the next trigger event. So this job can be done in normal sequential mode too.
In the mean time I was able to repair me 7T11 and made some tests therefore.
1. A 100ps pulse train with 30MHz rep. was feed through a S6 head to ext. 50 Ohm. Sequential trigger performed well. But random mode did not work correct, but sometimes a impulse was stable visible with signal portions appearing at "negative" positions, forming loops into the impulse.
2. A 100ps pulse train completely random (noisy, "full period jitter") was then used. Sequential trigger showed a random pattern in time and amplitude, as predicted. Surprisingly in random mode there was a stable impulse visible, but bend to the left, so risetime has to read as 0pS and no samples outside!! This is not declearable, because the internal prediction circuit can not foresee the next event, even with virtually no jitter!!!
Someone an idea about the strange behavior?
--GHz 09:24, 31 March 2010 (UTC)