Full Authority Digital Engine Control.
As simple as that...
It's just a computer system that takes in the various parameters like temperature, altitude, engine speeds, pilot's demand etc. and works out how much the fuel valve, variable guide vanes and air bleeds should be opened to get the best performance out of the engine.
Quite simple really, God alone knows why there are 50 or more of us trying to program the damn things here to keep up with the customer's changing requirements...
I still think we were better off with a Bowden cable between throttle and tap, no Bl**dy software to make a mess of things. Mind you, if that was so I would have been on the dole for the last fifteen or so years...
VnV...