Hi You may want to take a look at some of Bill Riley’s (and others) papers on how pre-filtering can lead to errors in an ADEV calculation.
Simply put - the frequency mode is a filter and it is not the right one to have in front of an ADEV calculation. Bob > On Apr 3, 2015, at 5:49 AM, Anders Wallin <[email protected]> wrote: > > Hi all, > > I ran some tests on a new 53230A counter that just arrived: > http://www.anderswallin.net/2015/04/keysight-53230a-noise-floor-test/ > > The time-interval single-shot noise and resulting ADEV seems easy enough to > explain. > > I didn't yet have time to look closely at Enrico Rubiola's notes over here: > http://rubiola.org/pdf-slides/2012T-IFCS-Counters.pdf > There is probably a good explanation for the ADEV-level in standard > (pi-counting?) reciprocal frequency counter mode as well as the roughly > 1/sqrt(10) enhancement in ADEV when increasing the gate-time 10-fold. > > on another note: > The discussion on phase-noise <-> ADEV calculations earlier was > interesting. Datasets (synthetic or real) with known correct ADEVs and > phase-noise-spectra would be a good addition to allantools and a motivation > to add code for the phase-noise <-> ADEV conversion. > > cheers, > Anders > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
