[time-nuts] High-end GPSDO's

[Ralph Devoe]

     I've seen several spec sheets on high end GPSDO's that seem to have
performance approaching a low-noise cesium standard, but only cost $3-6$K
new. One is the SRS FS740 which appears to combine a GPSDO with the
interpolator of the SR620 counter. This gets down below 10(-13) in one day
and drops below 10(-14) for longer times.  The other is the EndRun
Technology  Meridian II, which has been tested at NIST, as shown in
https://www.endruntechnologies.com/pdf/NISTReport-EndRun-MeridianII-US-Rb.pdf
.  This shows a TDEV <2 ns (according to NIST) and and ADEV that gets into
the 10(-15)'s for times longer than 1 day.
      Has anyone had any experience with these?

Ralph DeVoe