[time-nuts] Typical HP 5370B resolution ?

[Magnus Danielson]

Hi Poul-Henning,

On 03/04/2013 07:54 PM, Poul-Henning Kamp wrote:
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> In message<5134DD69.1070001 at rubidium.dyndns.org>, Magnus Danielson writes:
>
>>> Once you get to this level of detail, it is important to know that the
>>> actual number is not 20ps but 19.5763ps
>>>
>>> See page 8-19 in the manual.
>>
>> Since we are in nit-picking mode, on page 8-29 it says the resolution is
>> in 5/256 ns, which I get into 19,53125 ps (exact).
>
> I doubt that difference is material :-)

Me too. :)

> I'm not sure which one is correct, at the end of the day, but it is
> somewhere between 19.6078 and 19.4553 ps.

Well, the 5370B is also among the last precision counters that is geared 
to a precise geared resolution, where as most others have only a nominal 
ratio in the gear-box, some does not even allow for calibration of the 
interpolation ratio, but rather only allow for measurement and 
compensation of the interpolation ratio.

> The point I tried to make was that once you start to look really
> closely at good clocks, you will find that the resolution shines
> through, and it will be 19.55-ish ps, not 20ps.

On that we agree :)

Cheers,
Magnus