30-01-2016, 08:03 AM
I've had the Invotron video router up and running on the bench. My speculation about the double break in the video path was correct. It looks like each input to a 4051 switch is driven by an emitter follower. When an input isn't in use the video on that pin disappears and is replaced by something close to the +ve rail. I can see how this would work, using a single load resistor on the output of the 4051. However the "on" resistance of the 4051 is quite high so you'd need to use a current source rather than a resistor to get predictable gain. See the sketch.
Now need to see how the audio router interfaces to the video. There's a D15 "slave" socket on each. Need to find how this connects back to the processor card. Won't be using the processor but still need to hook up to its conenctor. This is a 48 pin (half width) DIN41612 socket. The spreadhseet shows where I've got so far.
Now need to see how the audio router interfaces to the video. There's a D15 "slave" socket on each. Need to find how this connects back to the processor card. Won't be using the processor but still need to hook up to its conenctor. This is a 48 pin (half width) DIN41612 socket. The spreadhseet shows where I've got so far.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
