[EMAIL PROTECTED] wrote: > > In a message dated 4/7/2007 04:08:20 Pacific Daylight Time, > [EMAIL PROTECTED] writes: > > > The Wavecrests are wonderful tools, but they address a different problem > than > what normal time-nuts usually care about, so they are not a given perfect > counter for long term comparision. It is aimed at jitter. > > > Hi Magnus, > > that's true for the SIA/SRT series of Wavecrest instruments. > > But the DTS series (DTS-2070, 2075 etc) have features that your SRT does not > have, for example cable-length measurement with picosecond resolution. > > The DTS units also have sophisticated external Arming features the SRT > doesen't have (two ARM inputs). > > They also have A to B time intervall measurements so one can do a DUT to > Cs/Rb comparison for example with +-25ps accuracy per measurement, at 40000 > measurements per second. Visi allows long-term high-resolution drift plots > that > can be turned into ADEV plots. > > Theoretically, this means +-25E-012 / rt(40000) = +-1.25E-013 measurement > accuracy per second if it's internal accuracy-noise is gaussian (I am not > sure > it is) so it would average out when comparing one 10MHz against another > 10MHz source. > > I don't have the Visi software so I cannot use the HiPer 40Ks/s option so > the above remains theory until I can find the software. > > Also, I don't think the SRT3000 can do two-input A to B measurements if I > remember correctly. > > As of today, there is a DTS-2070 on Ebay (search for "Wavecrest Digital Time > System") for $900 buy-it-now from a known-good vendor. > > In summary, I think the SRT is perfect for many-input parallel jitter > analysis, while the DTS is more of a traditional time-intervall-analyzer > suitable > for time-nuts usage. BTW: I think they both are not very good as true > frequency counters. > > bye, > Said > > > > ************************************** See what's free at http://www.aol.com. > _______________________________________________ > time-nuts mailing list > [email protected] > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > Said
Your theoretical resolution seems somewhat awry see: http://www.femto-st.fr/~rubiola/conference-articles/2005fcs%28rubiola%29-counters.pdf <http://www.femto-st.fr/%7Erubiola/conference-articles/2005fcs%28rubiola%29-counters.pdf> Bruce _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
