I'm wondering if my thinking is actually correct and whether this project is possible.
I'd like to have a 3 conductor wire between two boxes (XLR terminated Mic Cable). These boxes would have the ability to transmit and receive audio as well as voltage.
Without going into a whole lot of detail, could I use audio multiplexers to send and receive analog audio bi-directionally down two conductors that would also have voltage on them (that would be decoupled [if I'm using that term correctly]). My goal would be to send 2 discrete channels of audio, coming from two different sources on one side, and the same source on the other side.
Basically, trying to replicate an intercom system.
Would that be the way to do it? Or would it HAVE to be converted to digital first, then could be multiplexed, then converted back to analog on the other side?
If I understand what you question is correctly, then it should be no problem.
My advice would to be to go with a simple multiplexer such as the 74CD4051. It uses 3 digital select pins and then has 8 analog channels.
Its just your basic multiplexer. It is capable of demultiplexing as well, although I think most muxes are capable of demuxing but don't quote me on that.
You may run into an issue, say the person on one end is talking and the other interrupts the first, then you'd be sending data through a single channel. I have never tried that, although I suspect you would have some sort of issue. A possible fix is to just 2 muxes and have one for listening and another for talking. I can make a diagram if you need if that doesn't make sense.
That sort of makes sense, though a diagram would be helpful!
I'll likely have more questions after I see it.
It doesn't seem like it would be that difficult, and as far as interrupting one channel, that would probably be ok but I wonder if there's a way that I could mix the two of them in that situation, party-line style, rather than replacing.
card9inal:
These boxes would have the ability to transmit and receive audio as well as voltage.
Audio is transmitted over copper is voltage.
card9inal:
Would that be the way to do it? Or would it HAVE to be converted to digital first, then could be multiplexed, then converted back to analog on the other side?
Digital is also voltage. So whether you send an analog voltage or a digital voltage, it's still just voltage.
I understand that audio is voltage... I meant power, which we refer to as voltage in these situations. It would likely be +12V, or maybe +15V.
On any standard Whirlwind Q-Box that is used throughout the broadcast industry, there is an indicator light on top when it senses any voltage on the line, and no, it's not audio or digital voltage, but power. I'm sure there's a minimum amount of voltage needed to trigger the light to warn that there is something on the line that could damage some equipment. I just refer to it as voltage, since that's what most people are familiar with!
I get it... I do. I feel though like we're picking nits and have gotten away from the question I posed.
I think you all understand where I'm trying to go, and understand what my intent was. The "we" I mentioned are people in the broadcast industry. I think most people I run into on a daily basis would think along the same lines as I, and in fact, most have spoken the same way.
What would you like me to do to get this back on track?
card9inal:
I get it... I do. I feel though like we're picking nits and have gotten away from the question I posed.
I think you all understand where I'm trying to go, and understand what my intent was. The "we" I mentioned are people in the broadcast industry. I think most people I run into on a daily basis would think along the same lines as I, and in fact, most have spoken the same way.
What would you like me to do to get this back on track?
Thanks!
Yea, you wish to have the ability to switch between wires that carry AC low level audio signals as well as allow power to be distributed on the same wire(s) at the same time. Is that correct? If so what DC voltage level and what is the maximum DC current draw allowed? Such information is needed to be able to select the best 'switching' devices, be it relays or solid state components. A block diagram would also be useful to see what is what in your proposed interconnected system.