View Single Post
  #7   Report Post  
Posted to sci.electronics.design,alt.binaries.schematics.electronic
Jim Thompson Jim Thompson is offline
external usenet poster
 
Posts: 2,221
Default Automatic Audio Switch

On Tue, 31 Mar 2009 08:14:35 -0700, "RST Engineering \(jw\)"
wrote:

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-**** moments ;-)

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine Sometimes I even put it in the food