In that test I was just capturing the ADEV table from the TSC-5120 so don't have raw phase data.
I'm curious where you got the noise data for the TBolt gps engine -- that's far better than I've seen quoted before. The Trimble data sheet that I found specs the system PPS accuracy at 20 nanoseconds one sigma; they don't separately spec the GPS engine. (The data sheet for the current Thunderbolt E data sheet says 15 nanoseconds.) The USNO says that their filtered, linear fit time transfer measurements over a two day period, over the entire constellation, have an RMS residual of 4 to 10 nanoseconds without SA (http://tycho.usno.navy.mil/gpstt.html). That may not be apples-to-apples methodology, but it implies that sub-nanosecond results may be difficult to obtain. John ---- On Oct 7, 2011, at 4:16 PM, "ws at Yahoo" <[email protected]> wrote: > John > What was the RMS and PP phase noise for your 8e-14 test? > > Something to keep in mind is that although the Z3801 has a better Osc than > the typical Tbolt. > Long term, really low noise is all about the quality of the GPS signal and > engine. > > The Z3801's GPS engine is far inferior and not even close to the 10 to 100 > ps, 1 sec noise that a Tbolt engine has. > So how much does that effect the mid term GPS Phase noise which is highly > dominated by how good of antenna system one has. > Sounds like comparison is needed. > > ws > ************* > > Some test like these are on my list for this winter. I am planning to look > at a Z3801A versus a couple of 5061 class units: one with a high stability > tube that I think is in very good condition, and another with an FTS > replacement tube of probably typical surplus quality. I can also add a TBolt > into the mix. I'm hoping to lash up multiple 5334 counters in TIC mode so I > can do several comparisons simultaneously. > > In an early test of the 004 tube vs. Z3801A over a week or so, I saw what > looked like a floor in the 8e14 range. > > John > > _______________________________________________ > 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.
