[time-nuts] accurate portable time source

Tom Van Baak tvb at LeapSecond.com
Fri Dec 28 16:39:32 EST 2007


> This request is different than the last one.
> The most accurate TCXO watch is about 1 seconds/year, with regular
> wear and lots of adjustment. For at least 1 order of magnitude in
> accuracy, what can be made/bought given these initial requirements: it
> has to run of its own power supply for ~18 hours a day, and recharge
> fully at night. the device must be intrinsically accurate without be
> disciplined by an external signal, although that could be done at
> night. The size and wei8ght need to be pocketable such a a large cell
> phone.I am open to all suggestions and more/altered requirements.
>                                        Ronald.

Ronald,

Since a TCXO doesn't cut it, you could always try a miniature
OCXO. Take a look at Morion (http://www.morion.com.ru/) for
their tiny, low power, high stability, low drift quartz oscillators.

Do the math and see what the time error would be per month or
per year. Use lithium batteries; my guess is your 18 hour use
with 6 hour recharge requirement is easily met.

I don't quite get the "intrinsically accurate" requirement, though.
Time used to be something that you could have in isolation or
use in isolation but all the trends now are the other way.

No one predicted ten or twenty years ago that a billion people
today would have sub-second time (effectively, atomic clocks)
in their pockets or on their wrists. But that is exactly what radio
controlled watches, cell phones, internet enabled PDA's, and
personal navigation devices have done.

Send us a picture of your OCXO watch prototype when it's
ready! Combine that with one of these for extra credit:

Nixie Watch (David Forbes)
http://www.cathodecorner.com/nixiewatch/

The Nixie Tube Digital Wristwatch (Jeff Thomas)
http://www.amug.org/~jthomas/watch.html

/tvb
http://www.LeapSecond.com





More information about the time-nuts mailing list