I have a project on the drawing board that requires information from some sensors to be passed from a rotating platform via IR link.
This is basically going to be inside the generator next to the windings and I was worried about RF interference and the changing magnetic fields so I thought that going with IR would be better than RF.
The distance between emitter and receiver should be no more than 20 cm (it could be low as 10cm, depending on the mechanics of the generator, but I'm being conservative).
The bandwidth requirements (0.8 Mbps average rate per data channel, with possibly 3-4 data channels) necessitate some method of modulation that allow more bits per symbol.
I was considering PAM but it seems that one issue is how to calibrate for the change in brightness as the transmitter moves toward and away from the receiver. It doesn't seem I can use a reference calibration pulse at the beginning of the transmission since the distance between transmitter and receiver distance vary the entire transmission.
How is this normally handled? Is it just not possible with this PAM?