Hi It’s been a few years since I played with the TBolt delay. At least on the one I messed with, it only did modulo 100 ns moves. Anything finer grained than 100 ns simply was ignored.
Bob On Apr 27, 2014, at 11:32 PM, Tom Van Baak <t...@leapsecond.com> wrote: > Jim, > > Most (all?) timing receivers allow you to virtually shift the 1PPS forwards > and backwards to compensate for antenna delay or other factors. But the > physical 1PPS output will still have clock quantization and the only way to > deal with this is external h/w or s/w sawtooth correction. > > Imagine some GPS timing receiver with 50 MHz clock and 20 ns quantization. > Each 1PPS is one of those 50 MHz clock edges. The sawtooth correction is some > number between +/- 10 ns. If you were to add 1 ns to the antenna delay, the > 1PPS output would still be one of those clock edges, but the sawtooth > correction number would now be 1 ns less. So there is no electrical or > mathematical advantage in doing this. > > Speaking of which, has anyone watched what happens if you change the antenna > delay by 2000, 200, 20, or 2 ns in a TBolt GPSDO? > > /tvb > > ----- Original Message ----- > From: "Jim Miller" <j...@jtmiller.com> > To: "time-nuts" <time-nuts@febo.com> > Sent: Sunday, April 27, 2014 8:05 PM > Subject: Re: [time-nuts] New timing receivers? > > >> I spent some time reading the uBlox-6 documentation. I found the TIM-TP ubx >> message and format. I see that there is also the ability to feed back to >> the uBlox-6 time shift info for the PPS in 1ns increments. >> >> Does it make sense to feed the TIM-TP info back this way to provide >> correction? >> >> Or is an external delay line or TIC plus software the only way? >> >> Thanks >> >> jim ab3cv >> >> >> On Sat, Apr 26, 2014 at 7:59 PM, Jim Miller <j...@jtmiller.com> wrote: >> >>> I'm reading though the manual for my recently acquired M12+T which I'm >>> looking forward to using. >>> >>> I notice that the manual is dated 09FEB05. >>> >>> So the M12+T has been around for about a decade. >>> >>> Are there more recent timing receivers available now or has the ubiquity >>> of the consumer GPS market distracted all investment from timing receivers >>> except at the high end? >>> >>> Thanks >>> >>> Jim AB3CV > > > _______________________________________________ > 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.
