modulators and dtv/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?

[Gregg Lengling]

I think that is something that  is going to be slow to change.  You'll have to use an analog demod instead of using the Set as the demod for a while until everything is 8VSB....but don't hold your breath.  This is an after market thing and just think how long it took the market to develop all the modulators ect. since the inception of TV.

[Snard]

Most HDTV sets I've seen still have one or more composite video in jacks. I don't know what kind of signal is coming out of the security system, but if it's composite, couldn't you use that? Also, does each camera send on a separate channel, or is there some sort of switcher? (Inquiring minds want to know)

[Gregg Lengling]

Most common nowadays to is to modulate the security cameras on an RF channel as you can send it down a longer coax.  Thereby you have to have a NTSC receiver to receive and demod it. However they also make demod units but of course that jacks up the price for system.

[homthtr]

hi snard..

the video out signal from the camera's is a composite out, but these signals are modulated to either an air or cable channel so the customer can just tune the the modulated channel when they want to view the camera. The modulated signal is distrubuted throughout the house when combined with the incoming cable signal or in the case of satellite we would either diplex the modulated signal along with the satellite signal and undiplex it before the satellite receiver. Either way the customer uses the RF tuner in the set to tune to the "station" we creat with the modulator. The problem will be how to handle this situation in the coming years when the traditional off air tuners will no longer be installed in the tv's. Unless all new digital tuners will contunue to be able to tune the old signals. I'm figuring that any current modulators will be obsolite when the tuners in the sets are all converted to digital tuners. Which would be a major service call waiting to happen during the next few years. I'm  almost leaning toward not installing such systems in the near future until it's clear as to what the new modulators and tuners will be able to offer.

[mhz40]

Good question.  I don't think anyone has a good answer.  I would guess it would be similar to today's setup, only using a camera that puts out mpeg to feed a qam or 8vsb modulator for signal injection.
Another option by then may be a video phone or other device connected via TCP/IP... or do away with it all together.