MB
Mike Baker
Thu, Mar 16, 2017 2:32 AM
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
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
*****************
MG
Mike Garvey
Thu, Mar 16, 2017 5:06 PM
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@febo.com] On Behalf Of Mike Baker
Sent: Wednesday, March 15, 2017 22:33
To: time-nuts@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
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.
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@febo.com] On Behalf Of Mike Baker
Sent: Wednesday, March 15, 2017 22:33
To: time-nuts@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
*****************
_______________________________________________
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.
CA
Chris Albertson
Thu, Mar 16, 2017 5:29 PM
It COULD be very good. It would be easy for them to run NTP inside
the phone. But I don't think they do as battery life is "everything"
I think on IOS they periodically run SNTP.
I just as interesting question is how to measure the phone's display?
The biggest problem with all visual displays is the refresh rate.
Typically the screen is only updated at something like 60 Hz. You
have to establish a network connection to be able to see higher
resolution time. Not hard to do as Android is running Linux inside
and iPhones a Unix derivative You can
On Wed, Mar 15, 2017 at 7:32 PM, Mike Baker mpb45@clanbaker.org wrote:
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
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.
--
Chris Albertson
Redondo Beach, California
It COULD be very good. It would be easy for them to run NTP inside
the phone. But I don't think they do as battery life is "everything"
I think on IOS they periodically run SNTP.
I just as interesting question is how to measure the phone's display?
The biggest problem with all visual displays is the refresh rate.
Typically the screen is only updated at something like 60 Hz. You
have to establish a network connection to be able to see higher
resolution time. Not hard to do as Android is running Linux inside
and iPhones a Unix derivative You can
On Wed, Mar 15, 2017 at 7:32 PM, Mike Baker <mpb45@clanbaker.org> wrote:
> 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
> *****************
> _______________________________________________
> 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.
--
Chris Albertson
Redondo Beach, California
MC
Mike Cook
Thu, Mar 16, 2017 6:08 PM
Mine is a little over a second slow. Good enough for a date but not for any sort of nut.
Le 16 mars 2017 à 03:32, Mike Baker mpb45@clanbaker.org a écrit :
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
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.
"The power of accurate observation is commonly called cynicism by those who have not got it. »
George Bernard Shaw
Mine is a little over a second slow. Good enough for a date but not for any sort of nut.
> Le 16 mars 2017 à 03:32, Mike Baker <mpb45@clanbaker.org> a écrit :
>
> 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
> *****************
> _______________________________________________
> 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.
"The power of accurate observation is commonly called cynicism by those who have not got it. »
George Bernard Shaw
NS
Nick Sayer
Thu, Mar 16, 2017 7:10 PM
The time on mine is quite good, but I believe that’s because I have an Apple watch. If you pair an iOS device to an Apple Watch, I believe it suddenly “tries much harder” to keep its own clock in sync so that it can serve good time sync to the watch.
Apple has made grandiose claims about the accuracy of the watch, but human granularity for time is around 100 ms-ish anyway, so the bar is awfully high.
The time on mine is quite good, but I believe that’s because I have an Apple watch. If you pair an iOS device to an Apple Watch, I believe it suddenly “tries much harder” to keep its own clock in sync so that it can serve good time sync to the watch.
Apple has made grandiose claims about the accuracy of the watch, but human granularity for time is around 100 ms-ish anyway, so the bar is awfully high.
CA
Chris Albertson
Thu, Mar 16, 2017 7:31 PM
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@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@febo.com] On Behalf Of Mike Baker
Sent: Wednesday, March 15, 2017 22:33
To: time-nuts@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
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.
--
Chris Albertson
Redondo Beach, California
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@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@febo.com] On Behalf Of Mike Baker
> Sent: Wednesday, March 15, 2017 22:33
> To: time-nuts@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
> *****************
> _______________________________________________
> 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.
--
Chris Albertson
Redondo Beach, California
JH
Jim Harman
Thu, Mar 16, 2017 8:02 PM
There are GPS apps for phones such as GPS Test Plus for Android that
display the time as received from the phone's GPS. I'm not sure if phones'
GPS modules produce a PPS output, but it would be cool if an app could send
a tick to the phone's speaker/headphones on the second.
Le 16 mars 2017 à 03:32, Mike Baker mpb45@clanbaker.org a écrit :
Hello, Time-nutters--
Any thoughts on what the likely accuracy of smart phone time
displays might be?
There are GPS apps for phones such as GPS Test Plus for Android that
display the time as received from the phone's GPS. I'm not sure if phones'
GPS modules produce a PPS output, but it would be cool if an app could send
a tick to the phone's speaker/headphones on the second.
> > Le 16 mars 2017 à 03:32, Mike Baker <mpb45@clanbaker.org> a écrit :
> >
> > Hello, Time-nutters--
> >
> > Any thoughts on what the likely accuracy of smart phone time
> > displays might be?
>
> --
--Jim Harman
W
Wes
Thu, Mar 16, 2017 8:16 PM
My iPhone seems to be accurate to 5 minutes or so. There are two of them in my
house and they never agree. My computer is saying 1:15 PM local time, my iPhone
says 1:20PM
On 3/15/2017 7:32 PM, Mike Baker wrote:
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
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.
My iPhone seems to be accurate to 5 minutes or so. There are two of them in my
house and they never agree. My computer is saying 1:15 PM local time, my iPhone
says 1:20PM
On 3/15/2017 7:32 PM, Mike Baker wrote:
> 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
> *****************
> _______________________________________________
> 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.
>
P
Paul
Thu, Mar 16, 2017 8:49 PM
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
The iOS "Time" app/NTP client has been mentioned here before. It displays
the offset between the device and NTP time at the instant of sync. It
doesn't do that continuously though, you have force a new synchronization.
On Thu, Mar 16, 2017 at 3:31 PM, Chris Albertson <albertson.chris@gmail.com>
wrote:
> 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
>
The iOS "Time" app/NTP client has been mentioned here before. It displays
the offset between the device and NTP time at the instant of sync. It
doesn't do that continuously though, you have force a new synchronization.
SH
Severin Haas
Thu, Mar 16, 2017 9:32 PM
The German PTB has a nice widget (https://uhr.ptb.de) to see the actual
time + deviation ("Abweichung"). Can not test this from another location
than UTC+1h, but probably it works at your location.
Does anybody of you know how they are measuring the time deviation? Some
JavaScript Voodoo?
Am 16.03.17 um 20:10 schrieb Nick Sayer via time-nuts:
The time on mine is quite good, but I believe that’s because I have an Apple watch. If you pair an iOS device to an Apple Watch, I believe it suddenly “tries much harder” to keep its own clock in sync so that it can serve good time sync to the watch.
Apple has made grandiose claims about the accuracy of the watch, but human granularity for time is around 100 ms-ish anyway, so the bar is awfully high.
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.
The German PTB has a nice widget (https://uhr.ptb.de) to see the actual
time + deviation ("Abweichung"). Can not test this from another location
than UTC+1h, but probably it works at your location.
Does anybody of you know how they are measuring the time deviation? Some
JavaScript Voodoo?
Am 16.03.17 um 20:10 schrieb Nick Sayer via time-nuts:
> The time on mine is quite good, but I believe that’s because I have an Apple watch. If you pair an iOS device to an Apple Watch, I believe it suddenly “tries much harder” to keep its own clock in sync so that it can serve good time sync to the watch.
>
> Apple has made grandiose claims about the accuracy of the watch, but human granularity for time is around 100 ms-ish anyway, so the bar is awfully high.
>
> _______________________________________________
> 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.
>
