5 ms·

I, for one, hope that more research would be put into lowering the cost of atomic clocks, not into precision, so it is possible to put atomic clock into everyda

by terafo 5y ago

I, for one, hope that more research would be put into lowering the cost of atomic clocks, not into precision, so it is possible to put atomic clock into everyday devices.

Xpol 5y ago
They are not mutually exclusive. There're groups that are developing portable atomic clocks, and then we have this group that are pushing the frontiers. While not in everyday devices, cesium/ rubidium clocks which are less accurate but there're already commercial products that are used in observatories around the world. The standard time of your country might already be referenced to one of these.
- terafo 5y ago
  Actually, I think spending research time on lowering cost is much more beneficial to accuracy in the long run. It is possible to spend much more on research in case when there are tens of millions of devices produced each year, than in the case when these things cost a couple of grand per PCIe card, which is reasonable cost for servers, but not for consumer devices.
fsh 5y ago
It is usually much simpler to put a GPS receiver in the device and to make use of the dozens of atomic clocks flying over our heads. Or to use NTP over the internet.
- terafo 5y ago
  You can have hundreds of ms of error with these approaches, which is hard to compensate for.
  - omegalulw 5y ago
    With GPS you can measure time with <100ns person.
    - terafo 5y ago
      You should tell that to meta, since they are putting atomic clocks into each one of their servers, which is, according to you, unnecessary, because same or better result can be achieved by just constantly syncing with GPS.
      - dxdm 5y ago
        I think that's a fallacious argument. On the face of it, that they're not using GPS doesn't necessarily mean that it's because of a lack of precision. There could be other factors than precision that influence their choice.
      - Youden 5y ago
        You're assuming that Meta developed the Time Card [0] because GNSS or NTP aren't accurate enough. That's not the case, Meta tells us exactly why they developed it, in the "Why do we need a new time device" section of [0]. TL;DR: openness and software support. And they're not putting one in every server, they're using it as a reference for their new NTP-based timing protocol [1], with which they showed an uncertainty of only a few hundred microseconds. [0]: https://engineering.fb.com/2021/08/11/open-source/time-appliance/ https://engineering.fb.com/2021/08/11/open-source/time-appli... [1]: https://engineering.fb.com/2020/03/18/production-engineering/ntp-service/ https://engineering.fb.com/2020/03/18/production-engineering...
      - fsh 5y ago
        The atomic clock on their card performs much worse than the built-in GPS receiver. In normal operation, it serves no real purpose. I guess some bored engineers wanted to have something fun to play with.
      - 8note 5y ago
        They're also working on the metaverse, so they've got some weird choices overall. That's it's meta doing it doesn't magically make it the best . The big weaknesses of GPS are when you're accelerating and way up north or way down south where satellite coverage is poor
      - rcxdude 5y ago
  - Youden 5y ago
    Hundreds of milliseconds? A receiver like [0] is specced for single-digit nanoseconds. Even the standard-precision modules [1] are double-digit. My understanding is that GPS wouldn't function if the timing was inaccurate to several hundred milliseconds. [0]: https://www.u-blox.com/en/product/lea-f9t-module https://www.u-blox.com/en/product/lea-f9t-module [1]: https://www.u-blox.com/en/product/neo-m9n-module https://www.u-blox.com/en/product/neo-m9n-module
dguest 5y ago
Why do we need atomic clocks in everyday devices? Most everyday devices use quartz resonators, which, with some temperature stabilization, will gain or loose around 25 seconds a year [1]. As others have mentioned the clocks can be synced to other time sources (easily multiple times a day) such that this drift is always far less than a second. This is good enough for most everyday purposes. You mention in another reply that some companies are installing atomic clocks on servers. As I understand it this is mainly to deal with synchronization across distributed databases. Since most everyday devices aren't actually maintaining these databases they probably make due fine with quartz resonators. [1]: https://en.wikipedia.org/wiki/Quartz_clock#Accuracy https://en.wikipedia.org/wiki/Quartz_clock#Accuracy
- LASR 5y ago
  Well it’s for other things than just telling you what time it is. You could have a GPS that is far more precise. Or a altimeter that detects height changes based on gravitational time-dilation. There are tons of things you can build on top of precision timing. The use cases may have nothing to do with time, like in the altimeter case.
  - dguest 5y ago
    Giving your GPS the ability to calculate gravitational time dilation would be cool. According to Wikipedia [1] gravitational redshift is about 1e-16 per meter. Someone else posted a clock costing around $2k with a precision of around 1e-11 [2], so, the current commercial clock is giving us the elevation with a precision of around 100km. To get per-meter resolution we'd need 1e-16 precision, which is on par with the more "standard" clocks in research laboratories and better than the clocks we put on GPS satellites by a few orders of magnitude. Unfortunately that just puts us on par with an existing GPS. On the other hand, the bleeding-edge optical-lattice based atomic clocks described in this article give us altimeters with mm resolution. So we might actually be reaching the point where atomic clocks would be useful in "everyday devices". All it takes is for someone to shrink a tabletop experiment down to the size of a bar of soap, and to make it work without all the climate control, electromagnetic shielding, and vibration damping that come standard in a state-of-the-art atomic physics lab. [1]: https://en.wikipedia.org/wiki/Gravitational_redshift https://en.wikipedia.org/wiki/Gravitational_redshift [2]: https://www.sparkfun.com/products/14830 https://www.sparkfun.com/products/14830
reshie 5y ago
a lot of clocks sync to them. you can get table clocks that do as well.
fanf2 5y ago
The state of the art is the chip-scale atomic clock https://en.wikipedia.org/wiki/Chip-scale_atomic_clock https://en.wikipedia.org/wiki/Chip-scale_atomic_clock which came out of a research project at NIST. It is useful for devices that need good accuracy for long holdover times without radio reception. A Microsemi SA.45 CASC retails for around $1500.

by terafo 5y ago

I, for one, hope that more research would be put into lowering the cost of atomic clocks, not into precision, so it is possible to put atomic clock into everyday devices.

Xpol 5y ago

They are not mutually exclusive. There're groups that are developing portable atomic clocks, and then we have this group that are pushing the frontiers. While not in everyday devices, cesium/ rubidium clocks which are less accurate but there're already commercial products that are used in observatories around the world. The standard time of your country might already be referenced to one of these.

terafo 5y ago
Actually, I think spending research time on lowering cost is much more beneficial to accuracy in the long run. It is possible to spend much more on research in case when there are tens of millions of devices produced each year, than in the case when these things cost a couple of grand per PCIe card, which is reasonable cost for servers, but not for consumer devices.

fsh 5y ago

It is usually much simpler to put a GPS receiver in the device and to make use of the dozens of atomic clocks flying over our heads. Or to use NTP over the internet.

terafo 5y ago
You can have hundreds of ms of error with these approaches, which is hard to compensate for.
- omegalulw 5y ago
  With GPS you can measure time with <100ns person.
  - terafo 5y ago
    You should tell that to meta, since they are putting atomic clocks into each one of their servers, which is, according to you, unnecessary, because same or better result can be achieved by just constantly syncing with GPS.
    - dxdm 5y ago
      I think that's a fallacious argument. On the face of it, that they're not using GPS doesn't necessarily mean that it's because of a lack of precision. There could be other factors than precision that influence their choice.
    - Youden 5y ago
      You're assuming that Meta developed the Time Card [0] because GNSS or NTP aren't accurate enough. That's not the case, Meta tells us exactly why they developed it, in the "Why do we need a new time device" section of [0]. TL;DR: openness and software support. And they're not putting one in every server, they're using it as a reference for their new NTP-based timing protocol [1], with which they showed an uncertainty of only a few hundred microseconds. [0]: https://engineering.fb.com/2021/08/11/open-source/time-appliance/ https://engineering.fb.com/2021/08/11/open-source/time-appli... [1]: https://engineering.fb.com/2020/03/18/production-engineering/ntp-service/ https://engineering.fb.com/2020/03/18/production-engineering...
    - fsh 5y ago
      The atomic clock on their card performs much worse than the built-in GPS receiver. In normal operation, it serves no real purpose. I guess some bored engineers wanted to have something fun to play with.
    - 8note 5y ago
      They're also working on the metaverse, so they've got some weird choices overall. That's it's meta doing it doesn't magically make it the best . The big weaknesses of GPS are when you're accelerating and way up north or way down south where satellite coverage is poor
    - rcxdude 5y ago
- Youden 5y ago
  Hundreds of milliseconds? A receiver like [0] is specced for single-digit nanoseconds. Even the standard-precision modules [1] are double-digit. My understanding is that GPS wouldn't function if the timing was inaccurate to several hundred milliseconds. [0]: https://www.u-blox.com/en/product/lea-f9t-module https://www.u-blox.com/en/product/lea-f9t-module [1]: https://www.u-blox.com/en/product/neo-m9n-module https://www.u-blox.com/en/product/neo-m9n-module

dguest 5y ago

Why do we need atomic clocks in everyday devices? Most everyday devices use quartz resonators, which, with some temperature stabilization, will gain or loose around 25 seconds a year [1]. As others have mentioned the clocks can be synced to other time sources (easily multiple times a day) such that this drift is always far less than a second. This is good enough for most everyday purposes. You mention in another reply that some companies are installing atomic clocks on servers. As I understand it this is mainly to deal with synchronization across distributed databases. Since most everyday devices aren't actually maintaining these databases they probably make due fine with quartz resonators. [1]: https://en.wikipedia.org/wiki/Quartz_clock#Accuracy https://en.wikipedia.org/wiki/Quartz_clock#Accuracy

LASR 5y ago
Well it’s for other things than just telling you what time it is. You could have a GPS that is far more precise. Or a altimeter that detects height changes based on gravitational time-dilation. There are tons of things you can build on top of precision timing. The use cases may have nothing to do with time, like in the altimeter case.
- dguest 5y ago
  Giving your GPS the ability to calculate gravitational time dilation would be cool. According to Wikipedia [1] gravitational redshift is about 1e-16 per meter. Someone else posted a clock costing around $2k with a precision of around 1e-11 [2], so, the current commercial clock is giving us the elevation with a precision of around 100km. To get per-meter resolution we'd need 1e-16 precision, which is on par with the more "standard" clocks in research laboratories and better than the clocks we put on GPS satellites by a few orders of magnitude. Unfortunately that just puts us on par with an existing GPS. On the other hand, the bleeding-edge optical-lattice based atomic clocks described in this article give us altimeters with mm resolution. So we might actually be reaching the point where atomic clocks would be useful in "everyday devices". All it takes is for someone to shrink a tabletop experiment down to the size of a bar of soap, and to make it work without all the climate control, electromagnetic shielding, and vibration damping that come standard in a state-of-the-art atomic physics lab. [1]: https://en.wikipedia.org/wiki/Gravitational_redshift https://en.wikipedia.org/wiki/Gravitational_redshift [2]: https://www.sparkfun.com/products/14830 https://www.sparkfun.com/products/14830

reshie 5y ago

a lot of clocks sync to them. you can get table clocks that do as well.

fanf2 5y ago

The state of the art is the chip-scale atomic clock https://en.wikipedia.org/wiki/Chip-scale_atomic_clock https://en.wikipedia.org/wiki/Chip-scale_atomic_clock which came out of a research project at NIST. It is useful for devices that need good accuracy for long holdover times without radio reception. A Microsemi SA.45 CASC retails for around $1500.