Magnus, Excellent links, as always, many thanks. Much to digest. Clock comparison looks an interesting area.
Steve On 30 March 2010 13:12, Magnus Danielson <[email protected]> wrote: > Steve Rooke wrote: >> >> So there are 250 clocks, presumably, spread around the World and owned >> by the member countries of the BIPM. > > There is a fair spread geographically, yes. See map: > > http://www.bipm.org/en/scientific/tai/tai.html >> >> Their time is somehow compared centrally and an "absolute" time is >> determined from them. > > They are compared by various methods in a network style of operation. The > sites are compared against each other and the clocks of each site is > compared against the clock driving the network comparison. Hence, through > these steps phase differences can be cranked out. > > http://www.bipm.org/en/scientific/tai/clock_comparisons.html > > Equipment calibrations: > http://www.bipm.org/jsp/en/TimeCalibrations.jsp >> >> Each clock will then have a delta to apply to it's own time to provide the >> BIPM >> "absolute" time which then allows each member country to use its own >> clock for timing. >> > > Yes, out comes the delta of each individual clock as well as the individual > labs. These are reported upon regularly to be found in BIPM circular T: > > http://www.bipm.org/jsp/en/kcdb_data.jsp > ftp://ftp2.bipm.org/pub/tai/publication/cirt.266 > > Useful resource: > http://www.bipm.org/jsp/en/TimeFtp.jsp?TypePub=publication >> >> This sounds like a logistic and bureaucratic nightmare, I will have >> to look further as to how this is achieved. Any pointers gratefully >> accepted. > > I hope the above pointers get you started. > > They have spent some time cooking this up, yes. > > Toss into that, we have not really spoken too much about how they process > things. I can't tell you too much about it, except that I know that their > tool is called ALGOS. If someone could give me the appropriate articles I > would be greatful. > > Cheers, > Magnus > > _______________________________________________ > 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. > -- Steve Rooke - ZL3TUV & G8KVD A man with one clock knows what time it is; A man with two clocks is never quite sure. _______________________________________________ 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.
