Page History

...

In LCLS-I, the 476MHz MO provides an RF source to the timing system.  This signal is combined with a 360Hz signal derived from a sequencer chassis (i.e. derives a 360Hz signal coincident with the zero crossings from the 3-phase AC power line).  The 476MHz and the 360Hz signals are routed to the inputs of the VME-based Master Trigger Generator (VMTG).  The VMTG samples a 71.4kHz signal (a sub-harmonic of LCLS-I & LCLS-II MO frequencies) and generates a 360Hz fiducial that is aligned with the 71.4KHz signal.

(Borrowed from Timing for LCLS slide deck - see References section below)

...