[time-nuts] Low cost synchronization

Tom Van Baak tvb at leapsecond.com
Sat Aug 20 16:35:05 EDT 2005

> Just as with WWVB receivers, he does not have to have the GPS powered up
very long for and
> then only once a week or so to keep the oscillator tuned up. Once a GPS
solution has been
> found, the local time and the GPS solution time give a time-difference and
by remembering
> the GPS solution time from the last time you have the /|t you need to
calculate the
> frequency error. So, a GPS solution could be possible.

I'm curious what the power requirements are.

My Casio WWVB wrist watch works on one
battery for two years while my Casio GPS
wristwatch is lucky to run for more than a
two days, even when in intermittent mode.

> Depending on which standard you have, the phones only may have a sense of
"real" time.
> In GSM for instance, the phones traces network time only in a relative
aspect, but there
> is no real way to get an accurate UTC. The phones is being synchronised to
the base

This sounds odd to me given that cell phones
I've seen can display the date & time and they
appear to be accurate to a second.

All we need are some counter-examples. Does
anyone on this list have a cell phone that displays
the time of day with an error greater than a few
seconds? (if yours has a HH:MM-only display
compare the instant when MM changes). If so,
then Mike can scratch cell phones from his list
of accurate time sources.

By the way, Mike, have you considered if your
battery-operated, fob-sized, world-wide, low-cost,
synchronization device will be allowed through US


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