Lets try to put this into perspective ! Using the specs from the OLD hp 5061A which says it is intrinsically accurate to 1 part in 10^-11 means the following assuming it is exactly in error by a stable value of 1 x 10^-11 from the agreed upon central value :
1 x 10^-11 = 10 picoseconds offset If all you are doing is trying to keep your clock accurate to the one second level means it will take the following amount of time to accumulate a one second error in 10 picosecond increments: 100,000,000,000 seconds or 1,666,666,666.6667 minutes or 27,777,777.7778 hours or 1,157,407,40741 days or 3,170.97919838 years Plus or minus a little here and there as obviously the minutes, hours, days and years are not even numbers. So the extremely small drift may not even be noticable depending upon what you are doing. Bill....WB6BNQ Hal Murray wrote: > > I have a few GPSDO's (Trimble T-Bolt, Z3801A, TrueTime & HB units). > > How much better can the Cesium be than any of those ?? > > Here is another viewpoint... (I don't own a Cesium (but I'm looking) so my > opinions may not be relevant.) > > What are you after? What is important to you? > > Under the covers, a "Cesium" is just a CesiumDO with the PLL parameters tuned > to take advantage of what the Cesium tube can deliver. The basic time > constant is sub-second vs many-seconds for a GPSDO. > > If you are nutty enough, the GPSDO numbers don't really match what a Cesium > can deliver in the medium term time scale, say 1000-10000 seconds. I'm > pretty sure I've seen graphs of GPS time shifting slightly from night to day > due to atmospheric changes. A Cesium won't do that. > > On the other hand, a GPSDO won't have any long term drift. It's locked to > the best time we can get. If you wait long enough a Cesium will drift. Not > very fast, but it will drift. > > -- > These are my opinions, not necessarily my employer's. I hate spam. > > _______________________________________________ > 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.
