Appreciate the info guys.
I was really after something a lot more technical...
The FAA's AIM has some good info on ILSes and includes an illustration of a localizer and basically tells me that two beams come out of it, the left one modulated with a 90Hz signal, the right one modulated with a 150Hz signal, the carrier frequency being the localizer frequency. But there's no info on what happens from an avionics standpoint inside the aircraft receiver or indeed more technical detail on what the localizer is sending out.
Anyway, that's the sort of stuff I'm after - for no particularly good reason - its just been bugging me for a while and I wanted to try and understand the whole system
