[ntp:questions] Tighter regulation?

David Woolley david at ex.djwhome.demon.invalid
Mon May 20 10:08:55 UTC 2013


Mischanko, Edward T wrote:

> Does anyone know what setting can be changed that will cause
> tighter regulation of the offset.  My goal is to get clk_wander to

Why do you want to track network propagation delay changes, at the 
expense of accurate time keeping?

> equal as close to zero as possible more often.  I would also like
> to see the frequency adjusted with every change in offset data;
> it currently does not appear to do that; it seems to be random.

I think you are seeing the effects of the 8 stage minimum delay filter. 
  Defeating this is likely to increase jitter against true time, as it 
will cause the frequency to be adjusted based on low quality measurement 
samples, increasing the variability of the frequency.

Note that the time constants for the frequency adjustment loops are 
significantly larger than 8 times the sample interval.



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