Not on my box it ain't. The decoding of it on all the Sky Digiboxes I've used take a few seconds. 5 or 6 seconds is the average. Also I'm not saying TV networks would do that, I'm just saying it's a way of syncing them if they really wanted to.
I can see analogue, freeview and satellite on monitors in a row, with the output of the mixer in front of me. The satellite delay is less than two seconds. That's using domestic receivers.
ITV's channels certainly do incur much more of a delay which may be deliberate to try and make the multiplexing more efficient. Picture quality's still crap though.
IIRC different regions on the same transponder are deliberately
of sync so that they aren't displaying exactly the same thing at exactly the same time - there's obviously no point statmuxing several streams which are identical most of the time. This would mean therefore that the gap between analogue terrestrial and DSAT would depend on the region you are watching. Westcountry on DSAT is certainly a good 5 seconds behind the analogue terrestrial broadcast
If digital WAS the reason, then the Greenwich Time Signal surely would have been dropped from BBC radio due to digital radio being introduced. Even though this is a TV froum, I must say that the GTS must continue....
Bleep, bleep, bleep.... The is the BBC from London."
(sounds a bit like the BBC News theme)