[time-nuts] Smart Phone time display accuracy...?

Chris Albertson albertson.chris at gmail.com
Thu Mar 16 15:31:36 EDT 2017


Apple Support claims "within 50 milliseconds of the definitive global
time standard".  At least that is what Apple gives in their spec.

It might use difference source depending on which radios are enabled.
The phone does have GPS and a cell network radio and both can be used
for time.    But on a phone these radios are powered up and down as
needed.   I think best just to accept Apple's spec.

Again it would be fun to measure.  There is an API call to get the
system time.  One could write a simple app to send this out

Harder to know the specs on Android as there are so many manufactures
and versions and price points

On Thu, Mar 16, 2017 at 10:06 AM, Mike Garvey <r3m1g4 at verizon.net> wrote:
> CDMA mobile telephony needs system synchronization to +/- 10 uS in order to smoothly handoff a moving client from one cell to the next. Most systems use GPS to maintain this 10 uS.  This says nothing about how bad it could get after that.
> Mike
>
> -----Original Message-----
> From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of Mike Baker
> Sent: Wednesday, March 15, 2017 22:33
> To: time-nuts at febo.com
> Subject: [time-nuts] Smart Phone time display accuracy...?
>
> Hello, Time-nutters--
>
> Any thoughts on what the likely accuracy of smart phone time
> displays might be?   I am thinking that the stacking of delays
> along the path to its receive antenna plus any internal processing delays would accumulate to some unknown degree.  Any thoughts on this?
>
> Mike Baker
> *****************
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-- 

Chris Albertson
Redondo Beach, California



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