Thread

1. vesinisa · 1789708269 · focus · HN ↗

   Is it really so that Time Division Multiplex timing in cellular networks is based on NTP time? I stopped reading after the article implied this - it doesn't sound plausible at all.

   1. hdgvhicv · 1789719105 · focus · HN ↗

      I would assume it’s similar to dab etc, and it’s ptp that carried that data on IP. In the broadcast tv world we use ptp, or more traditionally black and burst, or word clocks in audio.

      The source is still the same - your grandmaster (ptp) or sync generator (b+b) is fed from a good timing source - often GPS, with one or two inputs, but sometimes local atomic clocks.

      I’ve seen issues before with 40ms audio gaps when a GPS antenna has died and the coders can’t cope with frame drift so they incentive a 40ms silence in the audio every 40 minutes or so as the source and destination clocks are different speeds by about 1 part in 60,000.

      In DAB the tolerances are far lower, there was a problem about 10 years ago due to a GPs satellite being a few microseconds off

      <a href="https:&#x2F;&#x2F;www.radioworld.com&#x2F;trends-1&#x2F;gps-anomalies-caused-problems-for-dab-around-the-uk" rel="nofollow">https:&#x2F;&#x2F;www.radioworld.com&#x2F;trends-1&#x2F;gps-anomalies-caused-pro...

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