[time-nuts] GPS signal simulator

WarrenS warrensjmail-one at yahoo.com
Thu Dec 11 21:23:07 UTC 2008



>> One of the questions I've needed to answers is just how good is good enough 
>> when it comes to making a high performance GPSDO.

>There is no single answer to this. One man's high-performance
>is another man's low-performance. It all depends on where you
>are in your quest.
 
>> Some of the self build units I've heard being used can be 100 to 1000 or more 
>> times worse than desired for best performance.
>> 
>> WarrenS

>That is correct. Because time can be measured more precisely
>than any other physical quantities it is quite normal for amateur
>projects or even professional products to span many orders of
>magnitude in performance. It is also true that the requirements
>have as great a span. Someone needing a time source simply
>for NTP (milliseconds) can get by with a solution a million times
>less precise than someone trying to tune the C-field of their own
>cesium standard (nanoseconds).
>
>/tvb
****************

My mistake, I should not of assumed as I did, that everyone would understand what 
"good enough" means for a "high performance GPSDO".
Good enough means: so as NOT to degrade the limited and available accuracy of the GSP signal.
i.e at least 3 to 6 db better than the noise. 
The correct answer is not a function of the user, it is a function of the GPS signal.

Warren


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