Tim, Perhaps a watchmaster G47? Very clever device, and yes, a fine mechanical example of a phase comparator. Google for it and see sites like: http://myplace.frontier.com/~dritland/watchmaster/
/tvb (i5s) > On Feb 10, 2014, at 12:01 PM, Tim Shoppa <tsho...@gmail.com> wrote: > > > IIRC some watch or clock company had a patent on calibrating a wristwatch > > crystal against AC hum. I read it once but can't find it now. Can you hunt > > for it? > > Tom - when I was a kid in the 1970's, before digital watches, the local > jeweler had device with a table on which a watch or clock could be placed, > the table must've been a microphone, and it had a pen recorder. It produced a > chart that looks like the "phase data" charts on yours and other websites; > the jeweler adjusted the clock so the recorded line had no slope. It had a > selector for several common watch/clock gear ratios (don't think it did the > tuning fork watches like the Accutron; I think there was a similar but > different device for checking the tuning fork Accutrons, my dad was enough of > a clock nut that he actually had a tuning fork Accutron, and he is a NAWCC > member still!). Over the course of an hour the adjustment could be fine > trimmed to the point where we knew the movement was good to a few minutes a > month. Don't know if it was locked to mains frequency or had a crystal. Do > you know what this was called? > > Tim N3QE _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
