Well you've got at least two options to do this with the current driver.
1) create and download an arbitrary waveform that contains the "pulse" pattern that you need and run that pattern and execute the arb function for each trigger
2) if a standard function (e.g. square wave at x hz) could generate the pulse, use burst mode to trigger a burst of one cycle of the waveform for every trigger.
The "Quick programming referance" for the 33120A and the user's guide explain a lot about how the AWG works Agilient should have these available for download but, you may need to call them as the 33120A is an obsolete unit.
"Should be" isn't "Is" -Jay
