[time-nuts] Low-long-term-drift clock for board level integration?

Bob Camp lists at rtty.us
Mon Feb 20 18:31:38 UTC 2012


Hi

Simple answer:

A rack mount cesium standard is as good as you can get. Figure on 15 ns per day of drift. That gets you to 15 us in 1000 days. You may or may not get one that drifts that little, a lot depends on  little details. For > 3 years, consider an ensemble of cesiums. At $50K each cost can go up pretty fast. 

There is nothing out there that will do better stand alone for less money. Either you get a sky view or you change the budget....

Bob



On Feb 20, 2012, at 1:32 AM, Bill Woodcock <woody at pch.net> wrote:

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> On Feb 19, 2012, at 10:20 PM, Dennis Ferguson wrote:
>> I think you may find that in many (most?) other
>> countries the GSM BTS gear has no idea what time it is.
> 
> Pretty wide range there…  I've certainly seen some pretty crazy time-and-dates show up on my phone upon landing in some countries.  But it's been a while since I've gotten a weird one in Europe or the more developed parts of Asia.  Africa and South and Central Asia are pretty much all over the map, though.
> 
>                                -Bill
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