[Bluecortina]

I'm surprised you weren't using synchronisers by that point?

We were. But each studio had its own SPG chain and the video signal path lengths to each studio was/would be different so even if you genlocked the studios together, which we did, the signal paths from the incoming Lines area where the synchronisers were through the various routing matrices to the actual vision mixers would likely be different - a small difference hence why we were able to use small Matthey delay lines to soak up the timing differences. The same would apply to other kit within the building, so for example, an in-house caption generator in the telecine area assigned as a remote input timed precisely into Studio 1’s vision mixer would not necessarily be precisely timed into Studio 2’s mixer at the same time. The studios were all designed to be standalone technically and it was only with the introduction of SDI that the studios moved over to a common set of pulses (from memory).