Hi While it may not be the only parameter worth considering:
The standard deviation of the delta between adjacent pps outputs goes down to below 500 ps on the LEA-6T when sawtooth is applied. Bob > On May 18, 2016, at 7:23 PM, Charles Steinmetz <csteinm...@yandex.com> wrote: > > Bert wrote: > >> Our first tests are with a 500 ps >> DS chip because I did have them, but 200 ps will work with a T5 or 6. We >> are also considering using two Micrel SY 89295UTG in series with 10 ps >> resolution, but with the limitation of a single frequency GPS receiver and >> ionosphere delay variations one has to ask does it make sense? > > Think first about what the GPS engine has to work with -- nothing but the > timing generated by its current GPS timing solution. It seems very doubtful > that sub-nS accuracy is possible. This provisional conclusion is supported > if we look at commercial GPSDOs using single-frequency GPS engines and > sawtooth correction (or using local oscillators that divide evenly by 100nS, > like the Tbolt). The best commercial units seem to place the PPS within 5nS > or so on a routine basis. > > So, even 500pS appears to be considerably better than necessary, given the > limitations imposed by the timing engine, atmospheric dispersion, and the GPS > system. > > Best regards, > > Charles > > > _______________________________________________ > 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.
