If you are simply talking about the rings that pulsate outwards, here’s how to set up the Emitter.
Set the Shape to Circle and the Arrangement to Outline.
Set the Emission Range to zero.
On the first frame set the Birth Rate to a large number like 1000.
Keyframe the value.
Step forward a couple of frames and set the value to zero.
Step forward about one second and set another keyframe (again at zero).
Open up the Keyframe editor and with the Birth Rate parameter selected, click on the tiny dropdown to the right of the control and select After Last Keyframe/Repeat.
That will create a set of continuously pulsing rings.
Test project here: 14105_pulastingrings.motn.zip
The oscillating rings are a bit more tricky but you didn’t ask about those.
Simon Ubsdell
hawaiki