[time-nuts] cheap 5V OCXO in 14DIP has about 1E-9 drift per day

[Bruce Griffiths]

Hal Murray wrote:
> bruce.griffiths at xtra.co.nz said:
>    
>> The 16MHz is necessary for the loop to function: The mixer mixes down the
>> 26MHz to a pair of conjugate frequencies, 10MHz  and 16MHz. Thermal and
>> device noise is sufficient to start the process.
>>      
>    
>> 10MHz = 26MHz - 16MHz
>> 16MHz = 26MHz - 10MHz
>>      
> What makes it stable at 10 and 16 MHz rather than 10.000001 and 15.999999?
>
> I'm assuming we are starting with a good 26 MHz crystal and that it would be hard to get filters that good.
>
>
>    
Asynchronous modes such as 10.000001MHz plus 15.999999 MHz can be 
problematic if the loop delay is too high.
http://www.femto-st.fr/~rubiola/pdf-articles/journal/1992im%28rubiola%29regenerative-divider-noise.pdf 
<http://www.femto-st.fr/%7Erubiola/pdf-articles/journal/1992im%28rubiola%29regenerative-divider-noise.pdf>

http://ieeexplore.ieee.org/Xplore/login.jsp?url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel5%2F26%2F23863%2F01093262.pdf%3Farnumber%3D1093262&authDecision=-203 
<http://ieeexplore.ieee.org/Xplore/login.jsp?url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel5%2F26%2F23863%2F01093262.pdf%3Farnumber%3D1093262&authDecision=-203>

http://tf.nist.gov/general/pdf/1800.pdf

Bruce