[time-nuts] Frequency comparison

Joop lous at xs4all.nl
Tue Feb 9 15:50:28 UTC 2010


??? I double checked the email I sent and it seems part of it did not end
up in the time-nuts archive.

Perhaps it did pass on in the emails to subscribers. Personally I find the
traffic on this list a bit much and disabled the email/digest. Because of
my moving around I use some webmail thingy. So I do not get the email
itself. It would be nice to have a yahoo-type webform to post on this list.
But hey, I am not complaining with all these knowledgeable people around. 

This is what I sent before of which only the first paragraph seemed to get
through.
hope it works now. If not I will quit trying to reduce the "noise".

> 
> I can understand. But I will not need that high accuracy very often. 
> So I just wanted to examine what can be expected after power-on. Just
> saving a bit of environment where possible.
> 
> From a Datum LPRO specifications document I read:
> 
> Warm-up: (at -20°C) (at 25°C)
> Time to Lock: < 8.7 min < 5.4 min
> Time to <1E-9: <10.2 min <7.3 min
> Time to <4E-10: <12.7 min <10.6 min
> 
> Frequency Retrace: <±2.5E-11
> (after 24 hrs power on @ 25°C & up to 48 hrs power off)
> 
> I guess my readings are all within the above specs. The retrace value is
> probably the limiting factor. 2.5E-11 translates in my setup to
90ns/hour.
> Which looks being reached already in about 2 hours after power-on. So if
> the Efratom is essentially the same as the Datum, then all looks fine.
> 
> Joop



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