Max Power wrote: > http://www.cl.cam.ac.uk/~mgk25/time/lf-clocks/ > The Digital Radio Mondiale standard for long/medium/short-wave digital audio > broadcasts (freely available for downloading as ETSI TS 101980) includes > time data, but like with RDS and DVB, the data format specification is not > really optimized towards high-precision clock synchronization and the DRM > COFDM demodulator needed is significantly more complex than the AM receivers > that decode the time signals listed above. > > It is a shame that the NTP.org has not set up a working group to define > packet formats for RDS / DVB / DRM / AMSS.
Digital broadcasting and studio->transmitter links, in general, present problems for time synchronization. All of the digital links have some amount of delay in the encoding/decoding process, the delay depending on details of error correction and the amount buffered up. There is a delay between studio and transmitter (now almost always a digital link esp in urban areas) and the HDTV and digital radio standards also introduce a delay. The studio->transmitter delay is somewhat under control of the station engineering, but even then they usually do not account for the delay in their broadcasts. The digital transmitter->home/car receiver has other issues because different brands and models of receivers have different delays. We have WWV and CHU decoders already in NTP and they're really very good. Tim. _______________________________________________ questions mailing list [email protected] https://lists.ntp.isc.org/mailman/listinfo/questions
