Tvam- Timeslot

[technologist]

That makes sense but would there not be a major splat between the two sources? I always remember watching at 0925 and there being a few seconds of black, with a split second of white as part of the splat - which we do see here - but I'm amazed the sound is completely unaffected.

If it was prior to 1989 I would expect the sound to be unaffected. ITV only started using Sound-In-Syncs when NICAM broadcasts started in 1989. Before then audio went via landlines

With NICAM itv would splat because it did not reframe the NICAM sequence
at the region or transmitter BBC did a reframe at TX ….
BTW both the Phillips/ PYE BBC flavour and the RE itv flavour DSIS was asynchronous
to TV Waveforms,
But both BBC and ITV NICAM subcarriers was a multiple (9x) of NICAM clock.