> Hi: > > I've been looking at the 4065B Cesium standard vs. GPS this month. After the > plot showed a slope of 472E-15 the frequency offset was changed from zero to > 472 on 8 May (gambling on the sign). For the next couple of days the points > all were in a box 20 ns high. BUT then the slope changed. It's now got a > positive slope that's very close to 472E-15 and the frequency offset is at > 472 > not zero. See attached plot. > > What might be causing this? For example the 4065B is just sitting on a chest > of drawers and might be moved or rotated a little from time to time. Is > there > a requirement that it be in a temperature controlled room on a concrete > pillar > to get into the E-14 area? > > It just turns on better than 5E-13 and the attached plot seems to indicate > that > it and be manually adjusted to parts in E-14 but so far I've not been able to > do that.
Brooke, At the level of e-14 and e-15 you might need weeks of data to separate the normal flicker noise from any clear frequency offset or drift trends. Yes, it's quite possible that environmental effects are also polluting your data. You can either control temperature, or just collect temperature data and see if there is a correlation with your standard. Do you have a continuous set raw GPS-Cs 1PPS data that I can look at to see if I can help you? /tvb _______________________________________________ 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.
