Modulators and HDTV

[homthtr]

currently we do a lot of combining of signals into either cable or antenna in housholds that have security cameras outside their front doors etc. giving them the ability to tune to a modulated channel to view their camera. Does anyone have a clue as to what will be available as a replacement to the current modulators so our customers will still be able to get the modulated signal combined with the new digital signals. As soon as the old analog tuners are obsolite how are the old modulators going to work in cunjunction with the new digital tuners?