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

[Mark Spencer]

From occasional observations of my IPhone 5 using the emerald sequoia emerald time application the "within 50 milliseconds" claim seems quite reasonable to me.

Mark Spencer




> On Mar 16, 2017, at 12:31 PM, Chris Albertson <albertson.chris at gmail.com> wrote:
> 
> 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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