= Сообщение: 6795 из 12550 ====================================== ENET.SYSOP = От : Gerrit Kuehn 2:240/12 16 Jun 18 21:51:20 Кому : Markus Reschke 16 Jun 18 21:51:20 Тема : Fiber connection to every household. FGHI : area://ENET.SYSOP?msgid=2:240/12+5a80ab54 На : area://ENET.SYSOP?msgid=2:240/1661+5b1d6a53 = Кодировка сообщения определена как: LATIN1 ================================= Ответ: area://ENET.SYSOP?msgid=2:203/2+5b257190 ============================================================================== Hello Markus!
16 Jun 18 20:41, Markus Reschke wrote to Björn Felten:
MR> I think you're talking about quartz crystals, i.e. the classic MR> 32.768kHz watch crystal. A quartz oscillator is the crystal plus an MR> oscillator circuit. For a precision time source you would take a TCXO MR> or go for a rubidium standard which aren't used for typical watches. MR> Of course quartz crystals got different tolerances based on the MR> quality and type of cut, but the frequency drifts with temperature. MR> Hence the TCXO. It doesn't make much sense to buy a quartz crystal MR> with a very low tolerance at a specific temperature when the MR> temperature can't be controlled, like in a wrist watch.
However, an TXCO is only a temperature compensated oscillator. For a precision application you will want to use a temperature controlled oscillator (OCXO). Beyond that, there are rubidium and caesium clocks. Or you just hook your device up to one of these by GPS, DCF, NTP...
