[time-nuts] cheap 5V OCXO in 14DIP has about 1E-9 drift per day
Bruce Griffiths
bruce.griffiths at xtra.co.nz
Sun Apr 10 20:24:28 UTC 2011
Bruce Griffiths wrote:
> Bruce Griffiths wrote:
>> 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
> Additional references that estimate the degree of tank mistuning
> permissable before asynchronous modes occur:
>
> http://www.its.caltech.edu/~kaushiks/KS_RFIC.pdf
> <http://www.its.caltech.edu/%7Ekaushiks/KS_RFIC.pdf>
>
> http://www.its.caltech.edu/~kaushiks/KS_TCAS.pdf
> <http://www.its.caltech.edu/%7Ekaushiks/KS_TCAS.pdf>
>
> An early implementation:
> http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=ADA457231
> <http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=ADA457231>
>
>
> Bruce
>
>
If one needs a frequency comb:
http://tf.nist.gov/general/pdf/2168.pdf
Bruce
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