GAD, I had NO idea that you could have a cesium-atom clock in a chip. That's amazing! What does one of these cost?
I want to say about $2000-3000...
Here's one for $2000 but no stock so no idea how old the listing is:
The Miniature Atomic Clock (MAC) from Microsemi uses a rubidium laser to output an extremely accurate clock. We're speaking at the edge of our knowledge so
www.sparkfun.com
What's fun about that is that Sparkfun is a site for people like me who make goofy stuff in their home labs.
I only know about them because early in the days of the company I work for we sold a switch with one on board so that it could be used as the grandmaster clock in a PtP network. I actually have one in my home lab and I was devastated to discover that at some point they had changed out the Chip Scale Atomic Clock (CSAC) for an Oven-Controlled Crystal Oscillator (OCXO) because the time accuracy on an OCXO is 10⁻⁷ or 10⁻⁸ at the 1/10th the price of for 10⁻¹¹ with an SCAC. Apparently while it was REALLY cool, people just didn't see the need for that level of accuracy over a network. It was shortly after that that I went a bit nuts and installed an amplified GPS antenna on my roof so I could have accurate time and a pure 10MHz signal to sync my test equipment.
Now, before anyone replies that poor time over a network should be obvious, the PtP protocol is really fascinating because the master and boundary clocks can actually compensate for the computational and propagational delay present in a network in order to deliver very accurate time. I don't know if it still is, but it was very common in High Frequency Trading 10 years ago.