Hi If you dig into the circuit, the resolution of the DDS is indeed 7x10^-13 per LSB.
Bob On Dec 9, 2011, at 9:51 PM, Bob Smither wrote: > Bob Smither wrote: > > <snip> > >> My documentation states that the full range of adjustment is: >> 7f ff ff ff => +383 Hz >> 80 00 00 00 => -383 Hz > > This scale factor is clearly wrong - using it and applying an appropriate > correction changes the frequency way too much. > > From: > > http://article.gmane.org/gmane.comp.time.nuts/9473/match=fe+5680+pin+outs > > (thanks Jose!) a better estimate is 140000 / Hz. > > Using data after 20 hours: > > http://www.c-c-i.com/node/155 > > the estimated frequency offset is 1.36E-3 Hz. Using the above scale factor > gives a correction of -190 counts. Here is the command I used to > (temporarily) program the new offset: > > 2e 09 00 27 ff ff ff 42 bd > > (the bd is the exclusive-or checksum of the offset) > > Now I wait ... > -- > Bob Smither, PhD Circuit Concepts, Inc. > ========================================================================= > A government which robs Peter to pay Paul can always depend on the > support of Paul. > --George Bernard Shaw > ========================================================================= > smit...@c-c-i.com http://www.C-C-I.Com 281-331-2744(office) -4616(fax) > <smither.vcf>_______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.