On Wed, Feb 08, 2023 at 07:18:17AM -0800, Richard Cochran wrote: > > BTW, synchronization with BCs can work better than TCs if the PLLs are > > well implemented and tuned. TCs are the simpler and safer approach. > > There was a simulation study showing "gain peaking" from a long chain > of servos.
Yes, but if you know the length of the chain and charateristics of all clocks and their timestamping, you can tune the servos to minimize their gain peaking for the synchronization of the last clock. This can be done with the pi servo in ptp4l. The linreg servo has significant gain peaking and is not configurable, i.e. unsuitable for longer chains. The way I think about the BC vs TC performance is that with BCs the noise is filtered on each link and what passes to the end is smaller than the sum of noise on all links, which is what it gets with TCs. This assumes the sync interval is sufficiently short for the instability of the clocks to not dominate the errors. -- Miroslav Lichvar _______________________________________________ Linuxptp-users mailing list Linuxptp-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-users
