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 time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts