[time-nuts] RE; New Wrist watch
Tom Van Baak
tvb at LeapSecond.com
Fri Sep 14 17:12:07 UTC 2012
Another rule of thumb is 1 second in a dozen days is almost exactly 1 PPM.
And two seconds before retirement (say, age 65) is close to 1 PPB. Three seconds a century is also 1 PPB.
Related to that, next time you read a newspaper article about atomic clocks I guarantee you'll see words like "one second in 3*** million years". That's because newspapers don't use scientific notation and because:
1e-9 is close to 1 second / 30 years
1e-12 is close to 1 second / 30 thousand years
1e-15 is close to 1 second / 30 million years, etc.
/tvb
----- Original Message -----
From: "Bob Camp" <lists at rtty.us>
To: "'Tom Van Baak'" <tvb at leapsecond.com>; "'Discussion of precise time and frequency measurement'" <time-nuts at febo.com>
Sent: Friday, September 14, 2012 9:14 AM
Subject: RE: [time-nuts] RE; New Wrist watch
> Hi
>
> Seconds per 30 day month turned out to be a pretty good unit for the watch
> module specs back in the dark ages. More or less divide by 2.5 (or 2.592 if
> you have a calculator) and you get ppm.
>
> Bob
>
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Tom Van Baak
> Sent: Friday, September 14, 2012 8:17 AM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] RE; New Wrist watch
>
>> So, does this unit include an input for a external reference? I would
>> be interested in knowing what they use for a timing reference...
>>
>> :)
>>
>> Dan
>
> Last I checked with Bryan, he has XO and TCXO and GPS options for the
> Microset timer.
> Realize that most traditional watch/clock people are content with ppm level
> accuracy/stability.
>
> /tvb
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