David Woolley wrote: > Uwe Klein wrote: > >> >> DCF77 for example is a "1 bit/s" transmission, a sentence taking 60s. >> It seems to not have issues with ms syncing. > > > That's because it transmits rather a large number of bits per signalling > unit. log2(resolution of timing of edge within second) bits of time > information are sent on any long or short signalling unit. (In > practice, you won't recover every bit on every measurement, so you need > several seconds to improve the signal to noise ratio. Once one is > synchronised, the number of useful bits drops greatly, because there is > a very high level of redundancy in the coding.) > > There is nothing in NTP protoco that guarantees that signalling units > are second aligned. However, one could get high resolution on very slow > links by making the transmit time represent the start of signalling unit > time, rather than the time the transmit request was queued. That would > require special, low level, drivers.
sure, you need a syncronised "carrier" or exact timestamps. But isn't that the basic assumption in all existing systems i.e edge or phase of the bitstream carries relevant information? uwe _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
