Atomic time
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You are perhaps familiar with the adage
If you have one watch you’re not sure if you have the right time, if you have two watches you’re sure you have the wrong time
Well, something like that. It has been a few months since I bought an ‘atomic’ watch that synchronizes itself with the atomic clock in Colorado. Occasionally, being on the eastern edges of the clock’s RF transmissions, my watch fails in its daily synchronization attempts, but other than that, I have been living in a world safe in the knowledge that I know exactly what the time is.
I wonder if people sense a certain smugness as I walk into a meeting. All who are already there are obviously too early and the ones who arrive after me are sadly too late. I on the other hand, am in perfect harmony with the cesium atoms hundreds of miles away. My watch is set to ring on the hour and it is not without a small sense of triumph that I hear its dutiful double beep just as the BBC newscast starts up on the radio. On the occasions that the two do not coincide I knowingly remind myself that I really cannot expect the BBC to be as perfect as us, my watch and I.
Today, I awoke at 6.30 as per my watch. Fall backward - the day we shift from daylight savings to standard time. The day we all get a glorious extra hour. I basked in the rectitude of being out of bed at 5.30 standard time. The oven clock showed 6.30 as well. I announced to the wife that the clocks needed adjusting when she helpfully advised me that she had already turned back the oven clock. F*&k. My little know it all watch had already set itself back. Actually I had suspected that the runt had in all likelihood compensated for the change in time (having had set it for ‘auto daylight savings’). But the little optimist in me had been holding out hope that little atomic had been either misconfigured or hadn’t picked up the signal from big atomic.
The bitter truth would take a while to sink in. Never is an awfully long time. But, I had been robbed of an hour and it would never be the same between the two of us again.
I sense this is the beginning of a great love affair between you and the perfect clock, tafkap. I envy you your synchronized perfection.
So, does the atomic clock take into account: the time to generate the RF signal from the atomic clock (modulation, amplification..etc), the time of flight of the RF signal from Colorado to your East Coast neighborhood, time to process that signal on your timepiece…etc..etc.
In other words, is perfect harmony, a few microseconds off that nth vibration of the caesium atom in colorado…and if so, are there a bunch of imperfect harmonies in concentric circles centered around Colorado.
You had to get all real and/or philosophical didn’t you
I wonder what all the effects really are. For example, relativistic effects such as changes in gravitational fields, my longer path through space (and consequently shorter path through time) relative to the ’stationary’ atomic clock.
As for the effects you mention, could one compensate for them? Suppose we could measure and compensate for the delays in the signal processing paths (clock circuits, watch circuits, optic nerve, brain :)). How about time of flight - without resorting to round trips? Maybe one could take advantage of refractive index of air. Generate two RF signals at different frequencies and use their separate arrival times to infer distance (I’ve filed a patent already).
As for the functioning of the atomic clock, I was intrigued that it has the appearance of a glorified pendulum.
http://www.eetimes.com/news/design/showArticle.jhtml?articleID=196600576