[time-nuts] Thermal impact on OCXO

Bob Stewart bob at evoria.net
Sat Nov 5 21:57:15 EDT 2016

Hi Scott,
The 20 bits span about 6 volts.  The EFC range spans about 8Hz (+/-4Hz).  I don't do these calculations every day, but that's about 4.5PPT?
Bob   -----------------------------------------------------------------



 From: Scott Stobbe <scott.j.stobbe at gmail.com>
 To: Bob Stewart <bob at evoria.net>; Discussion of precise time and frequency measurement <time-nuts at febo.com> 
 Sent: Saturday, November 5, 2016 8:38 PM
 Subject: Re: [time-nuts] Thermal impact on OCXO
I think that's a nice plot, it looks like you have stepped 160 LSB over 7 days or roughly 1 LSB per hour. With a 20bit dac you are trimming maybe 1 ppt/LSB to 4 ppt/LSB? In allan devation terms, the case of 1ppt/LSB, solely due to drift, you're at 1E-12 at 3600*sqrt(2) = 5000 s, in the case of 4ppt/hour your at 1E-12 at 1280 s. Seems reasonable.
On Sat, Nov 5, 2016 at 2:47 PM, Bob Stewart <bob at evoria.net> wrote:

Oh dear.  I attached the wrong file.  Here's the correct one.
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