Hal Murray wrote: > How do modern pendulum clock geeks measure what their pendulum is doing? I'm > picturing a magnet on the bottom of the pendulum and a coil or hall effect > sensor. > > > > > A variation on this would be optical as in CD reader technology. Put a > pattern on the bottom of the pendulum and then shine a light (IR?) on it and > detect the reflections. How far is the CD read mechanism above the surface > of the CD? Is it "flying" with an air bearing like disk heads? > Hal
A CD head is a non contact device. The head vertical position is servoed so that the recording layer is at the focus of a lens. No air bearings are required. The clearance can be several millimeters. Bruce _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
