[time-nuts] Solving the UTC drift problem

David Forbes dforbes at dakotacom.net
Thu Jul 14 03:15:45 EDT 2005

At 8:25 AM +0200 7/14/05, Poul-Henning Kamp wrote:
>In message <a05210601befba18cc387@[]>, David Forbes writes:
>>A modest proposal:
>>Instead of adding randomly-placed leap seconds to UTC or allowing UTC
>>to drift from UT1 etc, the timing community should just change the
>>second's definition from time to time as needed. That is, dither the
>>Cs transition frequency between 9,192,631,770 Hz or ,780 Hz annually
>>to make time speed up or slow down to match the earth's rotation.
>That has already been tried (1958...1972)  It was not a success.

I can see that it was not a success at the time, but the equipment of 
the time was rather primitive compared to today's digitally 
programmed electronics. It used to be difficult to synthesize a 
microwave signal with 10 Hz resolution; now it's done in less than a 
square mm of silicon.

However, the argument presented in the Metrologia article that 
physicists would not have a fixed SI unit called the second is a 
valid concern.

>>The beauty of this method is that there are only a few hundred Cs
>>clocks in the world,
>This number is probably one or two orders of magitude to low, but
>a lot of them are telecom timers so they can be ignored.

Tee hee. Yes, they don't what a second is, as long as each clock is 
consistent with the clock at the other end of the fiber.

Symmetricom would love this idea, as they would get to sell a lot of 
upgrade kits at monopoly prices.


--David Forbes, Tucson, AZ

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