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NIST Unveils Chip-scale Atomic Clock
grumling writes "The heart of a minuscule atomic clock, believed to be 100 times smaller than any other atomic clock has been demonstrated by scientists at the Commerce Department's National Institute of Standards and Technology (NIST), opening the door to atomically precise timekeeping in portable, battery-powered devices for secure wireless communications, more precise navigation and other applications. "
...Netgear can start manufacturing routers that don't totally fuck the NTP server at University of Wisconsin, Madison.
Tubal-Cain smokes the white owl.
Clarification, Cesium is a stable isotope and deos not emit radiation. It resonates naturally at microwave frequencies which is the oscilation that the atomic clock measures.
The original generic sig.
That's a very good way of getting blocked at firewall level. It's rather stupid too, since if you need so much precision just use NTP instead.
It is a wrong use of ntpdate as well. Its point is to set the time to the correct one at startup, since ntpd only makes gradual corrections and won't make time go backwards for example to avoid breaking things.
So, configure ntpdate to run once at boot, then start ntpd to keep it in sync.
Most of the time that is true but in this case, an atomic clock has a very precise meaning in scientific instruments. It is a clock that counts the vibrations of atoms to determine time intervals. Accoring to SI units a second is
Up until now atomic clocks like the ones used by NIST were large pieces of equipment. They were highly accurate but not very portable. Before, merchanical watches would lose seconds a day. With the use of quartz in electronic watches that dropped to about a second every 2 months. This lowers that bar even further. I'm not sure for what that level of precision could be used.
Well, there's spam egg sausage and spam, that's not got much spam in it.
So why don't you just use NTPd or OpenNTPd? And why aren't you using pool.ntp.org instead of picking on the poor, overloaded NIST servers?
A Cesium clock operates by exposing the Cesium-133 isotope to microwaves and measuring the frequency of the emitted spectral line. If you were measuring atomic decay and using one atom you'd get one decay. Then it'd most likely no longer be Cesium.
Where's the Kaboom?
There's supposed to be an Earth-shattering Kaboom.
There are about a jillion clock programs for windows that call the NIST clocks on a regular schedule of your choice and adjust the PC. Most of them are freeware. Some of them work with a clock display on desktop, some with the existing clock in the systray. I recomend Beatnik, at http://www.somedec.com/ free, skinnable, and stable, and no I don't have any connection to the author except using it and some of his other freeware. However, the OP apparently doesn't want to do something like that. I confess, I'm not sure why. If he has a box whose clock drifts by 5 min a day and that once daily ping is eating up substantial time on his connection, the answer is to get a new box or a faster connection. If my clock naturally drifted by 5 minutes a day, I'd want to correct about every 4 hours or so, or maybe I'd just immediatly try replacing the Mobo battery in case that was a sign it was going stale. Maybe I'm missing something there, and he just doesn't want to go through the process manually, but it sounds like he's more wanting to not do it at all.
Who is John Cabal?
> With a atomic clock in a GPS you no longer need to
> solve for time, so you can get the same quality
> position with one less satellite.
Not true! GPS receivers calculate their positions based on the difference in time of signals from at least 3 GPS satellites. Any fewer than 3, and the precise location can't be calculated. If a GPS receiver gets 3 signals, then exactly one spot on the Earth's surface could be at the intersection of those 3 signals with the measured difference in time from those signals. With only 2 signals, then many locations on Earth could receive those signals with the differences in time. All those locations are along the circumference of a circle many hundreds of kilometers wide.
> There are times where this could make a huge difference.
There are always at least 4 GPS satelites visible from any spot on the Earth. So, even if having an atomic clock in a GPS receiver could make a difference, it would not matter anyway.
You still can do it.
:00 minutes they get a ntp version of a slashdotting because people stick ntpdate in crontab.
Just run ntpdate when you connect instead of on boot. And kill ntpd before disconnecting. You can do this easily on Linux. On Windows I heard some programs exist to do this as well.
This is not about broadband arrogance anyway. ntpd uses much fewer server resources than ntpdate every second. In fact, many public ntp server administrators often complain about that every hour at
There are many NTP servers that are free to access out there. Please keep them that way by observing a simple netiquette.
In fact, the entire history of accurate time can be attributed to naval navigation.
The quality of clock in the GPS receiver makes a big difference in accuracy of the results. This is true both for navigation and timekeeping types. In any case, the time of the gps receiver must first be set to the time from the sat's but with corrections both for the delay to the receivers position and for the true gps time offset (around 13 seconds, if my memory is correct). Then based on the time held by the receiver, the position can be determined by the delay measurments of and position information in the signals. In the case of the 'position hold' mode used in timekeeping receivers, the time can be more accurately derived and produced. This is why some timekeeping receivers have options for the oscilators ranging from cheap (Motorola Oncore) to quartz to ovanized quartz to rubidium (cheap atomic) and beyond.
All the [published] papers are here in PDF form.
The one thing I can't figure out is how they make a resonant cavity this small
Others have been asking what's the use as one of their papers says:
If you know the time precisely you can lock up to the long frame encoded GPS signal without needing CA (more vulnerable to jamming).
Read about DNS round robin sharing of voluntary ntp servers:
http://www.pool.ntp.org
MM
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