Unfortunately "cesium passthru" went away with the advent of the use of frame synchronizers to receive the network signal and then re-clock it to match the local sync generator phase and frequency. The FCC requirement for the color burst signal (3.579545 MHz) is plus/minus 1 Hz... and you can certainly do better than that with most rudimentary oscillators. So, the phase stability of your local network affiliate is only as good as their local sync generator... Some stations do have sync generators with 10MHz EXT REF capability, allowing use of GPS or stabilized oscillators for that input... 73, Don, W4WJ In a message dated 5/25/2009 1:14:45 P.M. Central Daylight Time, hmur...@megapathdsl.net writes:
> Why did TV stations stop broadcasting time signals? HDTV requirements? One thing that may be relevant.... Many years ago, all the TV sources were kept in sync so there wasn't any glitch when they switched feeds. The sync timing was distributed from at atomic clock at network headquarters. The time of day probably piggybacked on that. I remember an old NBS booklet describing it. That was back in the late 70s. (It's probably a valuable collectors item now.) I think HP and NBS used to publish a table of delays for several major TV stations. Somebody on this list will probably recognize that description. The breakthrough that got around the timing requirement was frame buffers. (Thank Moore's law.) > Could a cable company interfere with the time signals? Thanks for the laugh. :) Cable companies do all sorts of strange things. -- These are my opinions, not necessarily my employer's. I hate spam. _______________________________________________ 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. **************A Good Credit Score is 700 or Above. See yours in just 2 easy steps! (http://pr.atwola.com/promoclk/100126575x1222377034x1201454326/aol?redir=http://www.freecreditreport.com/pm/default.aspx?sc=668072&hmpgID=62&bcd= MaystepsfooterNO62) _______________________________________________ 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.
