[ntp:questions] Two time sources with offset => fails to synchronize

Richard B. Gilbert rgilbert88 at comcast.net
Tue Feb 12 17:10:19 UTC 2008


Serge Bets wrote:
> Hello Thierry,
> 
>  On Tuesday, February 12, 2008 at 10:39:21 +0100, Thierry MARTIN wrote:
> 
> 
>>It seems that the Radio clock has 50ms offset compared to the GPS
>>source, which leads a failure in synchronisation.
> 
> 
> Radio clocks may need a fudge factor, typically around 20 ms, to report
> the right time. That's due mostly to filter delays in the radio
<snip>
 > Anyway even if all else gets
> perfect, you still have the worst number of clocks problem. One is good;
> two worst; four best.

Four is not necessarily "best".  It's the smallest "robust" 
configuration.  Five and seven are the next two magic numbers in that 
series.

One is not necessarily good or bad; the problem is, if it's bad, how do 
you know?





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