[sdiy] Tap Tempo

[D A F]

Hi all,

sorry if this might be a little off-topic, but here goes:

I was wondering if anyone knows how the more recent effects with "tap tempo"
(where the period of an LFO is synched automatically with the taps from a
foot switch) is implemented?  Does this have to be done with a processor of
some kind, or could it be done in analog?

thanks,

Dave