[time-nuts] FE-.5680A trimming resolution

Magnus Danielson magnus at rubidium.dyndns.org
Tue Jan 31 19:52:16 EST 2012


On 31/01/12 20:43, Attila Kinali wrote:
> On Tue, 31 Jan 2012 18:50:08 +0100
> bg at lysator.liu.se wrote:
>
>>> Let's say, i'm building a GPSDO with a high quality OCXO.
>>> Wouldnt it then make sense to lock the reference clock of the GPS
>>> receiver also to that OCXO?
>>>
>>> 			Attila Kinali
>>
>> Exactly that _is_ the appeal of the Tbolts.
>
> Yes, but can this be replicated with a standard GPS module?

Yes. If you look up old papers, they already did this with Oncores, 
Cesium clocks and synthesis.

> And does it have side effects?

If you've done it right, it lowers the receivers noise. The position 
becomes less shaken by the jerk effect of the oscillator noise, while 
frequency and drift also affects the solution to some degree. This 
side-effect is covered in literature if you look for it.

>> What frequency does the uBlox
>> 6T TCXO have?
>
> 48MHz as stated in the Timing AppNote.

Produceable.

>> Let us know your progress.
>
> My current progress is that the uC i wanted to use does not
> do what i want. Can anyone recommend a uC with 32bit timers
> and IEEE 1588 support?
>
> The alternative would be to use an FPGA, but i'm reluctant to
> do that as it makes the whole system a lot more complex

No pain, no gain?

Cheers,
Magnus




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