Gary E. Miller writes: > Last week we had a discussion on sys_fuzz and the value of adding > random noise to some measurements. The code defi2nes sys_fuzz asL > > "* The sys_fuzz variable measures the minimum time to read the system > * clock, regardless of its precision." > > Rondomness of half the sys_fuzz is then added to some values, like this: > > fuzz = ntp_random() * 2. / FRAC * sys_fuzz > > Makes no sense to me. Adding randomness helps when you have hysteresis, > stiction, friction, lash and some other things, but none of those apply > to NTP.
https://en.wikipedia.org/wiki/Dither You might have enough other noise in any particular system so the sys_fuzz (which whitens the quantization noise on the clock reading) doesn't make a difference or you might not. But presumably Dave Mills didn't put it in there just because he was trying to add useless code. > So I took two identical RasPi's and forced sys_fuzz to zero on one of > them. Four days later I can see no difference in the results from > those two. Which proves exactly nothing. Regards, Achim. -- +<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk Blofeld]>+ Waldorf MIDI Implementation & additional documentation: http://Synth.Stromeko.net/Downloads.html#WaldorfDocs _______________________________________________ devel mailing list [email protected] http://lists.ntpsec.org/mailman/listinfo/devel
