On my iPhone, I run an NTP client, Emerald Time, that displays the offset between NTP time and the device's internal clock.
I'm on T-Mobile US and the offset is typically in the low tens of milliseconds or better. It's certainly accurate enough as a clock where all I'm looking at is one minute resolution. Glen Hoag h...@hiwaay.net Sent from my iPhone > On Mar 18, 2017, at 09:52, John Hawkinson <jh...@mit.edu> wrote: > > Chris Albertson <albertson.ch...@gmail.com> wrote on Fri, 17 Mar 2017 > at 14:38:17 -0700 in > <CABbxVHsRa41HoB=xu4nk4t_c39uh2bcomu17nb7h3ra8uhx...@mail.gmail.com>: > >>> AndroiTS GPS Test (V 1.48 Free) is good, but a battery hog I find. On > >> THIS is why the phones don't really track time so well. Not that they >> can't but doing so requires battery power. > > This statement doesn't seem to be well-supported. I think it's > basically untrue if we're talking about timing at the tens of > millisecond level. Anything more precise seems relatively useless in > a smartphone without specialized mechanisms to get the time off of the > phone. > > A phone's GPS receiver takes a lot of battery. But GPS is not the primary > mechanism that phones use get their time. > > They get time from the cellular phone network (whether from the layer > two timing information or at a higher layer with something like > NTP). The effort required to keep a phone's clock in sync, even with a > really bad local oscillator, is lost in the noise of all the other > things the phone has to do. It's just not a battery issue. > > The only reason modern smartphones keep bad time is because their > designers can't be bothered to do better, or possibly the network is > providing "bad" time to the phone. (Unless I'm missing something.) > > --jh...@mit.edu > John Hawkinson > _______________________________________________ > 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.