This is exactly why we have disciplined oscillators: the short term stability of an OCXO steered with the long term stable accuracy of GNSS, Cs beam/fountain or H maser.
On Thu, Feb 20, 2020 at 7:41 PM Taka Kamiya via time-nuts <time-nuts@lists.febo.com> wrote: > > I have a question concerning frequency standard and their Allen deviation. > (to measure Allen Dev in frequency mode using TimeLab) > > It is commonly said that for shorter tau measurement, I'd need OCXO because > it's short tau jitter is superior to just about anything else. Also, it is > said that for longer tau measurement, I'd need something like Rb or Cs which > has superior stability over longer term. > Here's the question part. A frequency counter that measures DUT basically > puts out a reading every second during the measurement. When TimeLab is well > into 1000s or so, it is still reading every second; it does not change the > gate time to say, 1000s. > That being the case, why this consensus of what time source to use for what > tau? > I recall reading on TICC, in time interval mode, anything that's reasonably > good is good enough. I'm aware TI mode and Freq mode is entirely different, > but it is the same in fact that measurement is made for very short time span > AT A TIME. > I'm still trying to wrap my small head around this. > > --------------------------------------- > (Mr.) Taka Kamiya > KB4EMF / ex JF2DKG > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
