); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY In message <[EMAIL PROTECTED]>, [EMAIL PROTECTED] writes: >); SAEximRunCond expanded to false
>This brings up another question: how good are true PID loops that also make >use of the differential term (e.g. correcting for rate of change of the >phase)? The literature talks about the differential term being hardly used in >the >industry because it can add noise and instability to a system... I tried it and found that you could indeed et faster convergence, but I did it with a HP5370B as phase comparator to minimize the noise. With more realistic phase comparators I don't think it is sensible. I personally prefer to start with a very short tempered PLL and then increase the timeconstant as things get better. The hard part is knowing when to stop increasing the time constant, and I have found that keeping track of phase error zero crossings is the best indicator: If you don't see any (for too long time), your PLL has too long timeconstant. Poul-Henning -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 [EMAIL PROTECTED] | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
