Various "time-nuts" start off with GPS disciplined rubidium clocks, or radio clocks like WWVB, and derive a phase-locked 60Hz to run the old-fashioned 120VAC continuous-hand-movement analog and flip clocks (in my circle known as "NUMECHRON"s although I think the most applicable trademark was TYMETER). One example is: http://leapsecond.com/pages/atomic-nixie/ Obviously an HP 3325B is overkill as a 60Hz synthesizer but you get the idea. If you have WWVB carrier, 60Hz is just dividing by 1000, no funny numerator/denominator stuff.