On 2010-09-14, David L. Mills <[email protected]> wrote: > Miroslav, > > I think we are talking right past each other. Both Chrony and NTP > implement the clock discipline using a second-order feedback loop that
chrony does not use a second-order feedback loop it is a high order, and variable order feedback loop. It remembers not just the slope and offset, as does ntp, but also past values of the errors. It is, as far as I can tell, stable ( poles in the lower have complex t plane.) The variable order also makes it non-linear. The high order and the non-linearity both make it very different from ntp. > can minimize error in both time and frequency, although each uses a > different loop filter. Chrony uses a least-squares technique; NTP uses a > traditional phase-lock loop. The response of these loops is > characterized by risetime and overshoot, or alternatively time constant > and damping factor. If Chrony were designed to have similar risetime and > overshoot characteristics and equivalent time constant, when operated > under the same conditions (trace 1) it will perform in a manner similar > to NTP. That was and is my claim. .. _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
