Re: PG506 trig out jitter?


On Thu, 5 Jul 2018 at 15:04 Albert Otten <aodiversen@...> wrote:

The trigger output and the Hi Ampl output are in phase square waves. The
fast up-going edge of the trigger corresponds to the fast up-going edge of
the Hi Ampl when it switches from negative to zero.

Right - same polarity on the edges, thanks. The manual spells this out, I
guess I could have read it rather than speculate. But where's the fun in

The slower down-going edge of the trigger corresponds to the down-going
edge of the Hi Ampl.
Mmmm, slower meaning non-reference. It's not clear to me why this edge
would be slower, but maybe that's just me. The output is driven towards the
negative, but the rising edge is entirely at the mercy of the 600 Ohm
output shunt and any capacitance downstream from there.

If you want to destroy your PG506 then try to"flip" the Hi Ampl output the
way you suggest.
Looks like I've misunderstood the point of the "ground" switching. The
STD/High output connector is insulated, and so doesn't have the shell of
the BNC connected directly to the case. The shell is in fact switched
between two different "grounds" depending on the mode, and I had somehow
assumed from there that the high-amplitude output was not referenced to
On a second reading of the schematics, it appears that this is not the
case. I'm not sure, but perhaps the switching is so that the shell of the
output connector is connected to the very center of a star grounding system
in STD amplitude mode? This would make sense as those are getting to be
quite low-level signals towards the bottom end of the range...

All that being said, flipping the output of the hi ampl output will "just"
short it through the common ground between oscilloscope and the PG. I doubt
this would destroy it - not that I'm about to try it :).

The proper way is to build in a level shifter in your pulse generator. See
the schematics of 067-0681-00.
Yups, that's what I did, but sadly (presumably) the slow rise of the high
ampl output is leading or contributing to jitter from sync out to the fast
edge that's 15 times the rise of the pulser.

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