On Feb 12, 2012, at 11:36 PM, Dave Hart wrote: >> Agreed, temperature swings will have a major impact on the crystal frequency. > > Well, I know what you're saying but we're talking on the order of 1 > PPM / degree C.
Yeah, on that order. It's noticeable, or can be anyway, but also well within the tolerances that ntpd will handle just fine. >> You might be able to improve the stability of the crystal by ensuring good >> airflow and cooling via HVAC as needed. And I suppose you could adjust the >> rate by changing the HVAC set-point, but I don't think the benefit is worth >> it. >> >> I'd be more likely switch to an OXCO + GPS on a PCI/PCIe card if such as >> needed. > > That's OCXO, oven controlled crystal oscillator. Why X for crystal? > Christ if I know. There's a great article at > > http://en.wikipedia.org/wiki/Crystal_oscillator > > that includes a table of abbreviations you can refer to. Yes, "OCXO". Electronic schematic diagrams use single or two letter abbreviations, and "C" was already taken (for "Capacitor"). I seem to recall a crystal is actually "Y" if using a single letter, or "XO" for two letters.... Regards, -- -Chuck _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
