Interesting, I had never read AES11 before, I see they are not just scaling to the facility but to drop hints of worldwide synchronization in there. I would like to compare/contrast the evolution of digital timecode distribution (AES11 spec for 1ppm), with where nationwide conventional TV distribution was 40+ years ago (proposal for using for time-transfer with sub-microsecond jitter and microsecond level drift over several months): http://tf.nist.gov/general/pdf/237.pdf
On Mon, Apr 28, 2014 at 4:19 PM, Magnus Danielson < [email protected]> wrote: > You actually have to look in AES11 and see that Grade 1 is specified to be > within +/- 1 ppm with a minimum capture range of +/- 2 ppm while Grade 2 is > +/- 10 ppm with a minimum capture range of +/- 50 ppm. > > AES5 does give you the +/- 10 ppm minimum requirement for the source, but > nothing about the receiver. > > Cheers, > Magnus > > > On 04/28/2014 02:45 PM, Tim Shoppa wrote: > >> I suspect the TCXO might not have enough range because fundamentally the >> VCTCXO are only 10ppm range and your AES3 source could well be much >> further >> off unless it is being run from a better master clock than a TCXO. >> +/-50ppm >> is the hope for pro-grade AES3 streams. I think AES5 is aiming towards >> clock rates in the 10ppm ballpark. >> >> >> >> On Mon, Apr 28, 2014 at 2:41 AM, sg sg <[email protected]> wrote: >> >> Thanks very much for your responses! >>> >>> For 24.576 MHz VCXO, the fractional change in frequency will be in >>>> >>> multiple >>> >>>> ppm not octaves, and I would naturally gravitate towards a simple diode >>>> >>> DBM. >>> >>> To avoid lock issues I'd still want a phase-frequency detector; the PLL >>> bandwidth in my case is very low (a few Hz), which makes the lock range >>> tiny if a "phase only" detector is used (I've run into this recently with >>> some other project). >>> >>> 24,576 MHz is 128x192 kHz which makes essentially any divide by 2^N chip >>>> capable of the frequency a target. Is your reference signal also 24,576 >>>> MHz or some other frequency? >>>> >>> >>> The source is an AK4114 AES/EBU audio receiver, which has both master >>> clock (24.576 MHz) and "word select" rate (48-192 kHz) outputs. Perhaps >>> it >>> is better to run the PLL at the latter? Any disadvantages from this? >>> >>> Regards, >>> Samuel >>> _______________________________________________ >>> 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. >>> >>> _______________________________________________ >> 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. >> >> _______________________________________________ > 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. > _______________________________________________ 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.
