I suppose once you're in the domain of crystal oscillators, the line between "mechanical" versus "purely electrical" is a bit fuzzy. The mechanical/thermal effe

I suppose once you're in the domain of crystal oscillators, the line between "mechanical" versus "purely electrical" is a bit fuzzy. The mechanical/thermal effects of passing a high-frequency signal through passive components (or a transmission line) might be comparable to the mechanical vibrations of a quartz clock, though somebody better at physics could probably correct me.