Hi Jim: With just 2 standards you don't know which is the best. Someone has to make an additional box so there's at least 3 to test. This way you can rank them.
A timing grade GPS receiver is very handy for this sort of thing. By measuring the time interval between the GPS 1 PPS output and your local standard you can see how well your local standard is doing. A good way is to make an Allan plot. Have Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Jim Palfreyman wrote: >Hello, > >Let me introduce myself. I've always been interested in time and more and more >accurate clocks. I have built myself a GPS disciplined HP10811 clock (Murray >Greenman's design) and it all works very nicely. I have acquired the old >Australian "Speaking Clock" hardware and am driving it from my GPS clock. So >it's "Pretty accurate". I broadcast the speaking clock output within a few >100m of home on FM 107.7 using a very lower power (hence legal) transmitter. A >great hobby and impresses the friends. > >However I have a general question and I don't really know the answer. And I >bloody should! > >If one of you walk into my workshop with your caesium clock and we plonk it >down and make comparisons to my HP10811 clock we could compare the two, look >at drift, phase noise etc. We would know the caesium is better and we would >watch my clock drift with respect with that. No arguments. > >So I walk into your workshop with black box A and compare it to your black box >B. We have no idea whether either is a rubidium standard, a hydrogen maser or >a wrist watch. > >How do we know which is the more accurate timekeeper? > >Keep in mind we have no other units to compare with. Only these two. > >The reason for my question? How do we know when someone has invented a more >accurate device to measure time? > > >Regards, > >Jim Palfreyman > > >-- >www.tasmail.com > > > >_______________________________________________ >time-nuts mailing list >[email protected] >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > > _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
