Automatic Audio Switch

We do something along those lines in avionics, but it turned out to be less than useful. We called it priority encoding. That is, you have a number of inputs (say 4 for example). You put the most important signal on channel 1 and you use a simple diode detector to see if there is any audio on this channel. IF so, THEN shut off the other 3 channels with gates and the usual audio analog switch like a 4016. Then IF no audio on 1, then the second priority line uses the same detector and IF audio on this channel, THEN shut off 3 and 4. And so on down the line. 4 needs no detector. If there is nothing on 1, 2, or 3, then 4 is a pass-through.

The problem we found in actual service is that you'd be listening to something rather important on line 2 when line 1 came on calling another aircraft and shut off #2. Not a good thing. I think I've got the prototype around in the "that was a hell of a good idea" box somewhere.

Jim

Sno-o-o-o-ort! One of those aw-s*it moments ;-)

...Jim Thompson