Mark Sims wrote:
> I doubt the temperature sensor is just used for environmental monitoring.  If 
> it was,  they would most likely have just used the basic 0.5C resolution 
> reading and have been done with it.    Instead,  they do the high res read 
> routine and then feed that into a filter to get very smooth high resolution 
> (microdegree scale) values.
>
> The whole purpose of a GPSDO with an expensive double oven OCXO is to provide 
> extremely high quality holdover performance when GPS signals go away.  To 
> achieve this level of performance one needs to compensate for the affects of 
> temperature on the parts of the system outside the oven.  0.5C resolution is 
> not up to the task of maintaining parts per trillion accuracy.   There does 
> not appear to be any other temperature sensor in the Tbolt.
>
>
>
> ------------
> Isn't it likely that a temperature sensor adjacent to the RS232 connector  is 
> just going to monitor unit temperature for environmental  purposes, perhaps, 
> for example, to give the option for flagging up an  overheating situation, in 
> which case surely 0.5C resolution is more than  adequate and the "clunkiness" 
> isn't really an issue?
>   
Mark

Unless there is sufficient noise or dither merely filtering/averaging a
large number of temperature readings will not increase the resolution to
below 1lsb.
Either internal noise or temperature fluctuations with an amplitude of
at least 1 lsb or so are necessary.


Bruce

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