I've been using things like the TSOP38238 to get modulated infrared messages sent over a line-of-sight link. but I've been wondering about how to do this for higher data rates, and failing to find anything via online searches which seemd to fit the data rates I'd like.
You see, when one works at the 38KHz carrier frequency which that sort of receiver is tuned for one needs >10 pulse repetitions for each bit in your data (if you use a position based encoding, lonegr still if using pulse length encoding), so this comes out to a maximum rate of 3.8KHz for data (lower still when you factor in starting and ending patterns in the transmission formats one might choose to use). I'd like to get a LOT faster, hundreds of times faster. So I'd be looking at something like the TSOP38238, a demodulating receiver with inbuilt flltering, gain control and output digitisation stuff, but rated not for 38KHz but for maybe 3.8MHz or higher still. Anything above 1MHz would be good, a few tens of MHz would be evry nice, the higher the better really, I'm not really looking above 100 MHz, but if that is the only option I can maybe go there too. I can adapt other things in the system so as to generate however fast a carrier I need, so it need not be a multiple of anything, and I can find ways to make it which aren't reliant on an arduino directly and so I need not worry about what the limits of ATMega clock speed
For high data rates I can find lots of little RF devices, but I don't want to touch RF, I want to keep my stuff entirely LINE-OF-SIGHT, for various very deliberate reasons. So I'm after an IR receiver which can handle these sort of frequencies, and for that matter, if a typical IR led can't blink with fast enough rise and fall times I'd be after a corresponding IR LED or modulating transmitter module which can keep up with such a >1MHz receiver.
Search engines give nothing about IR receivers faster than about a 56KHz carrier, and checking on various electronics sellers websites for items closely related to the TSOP38238 also only gives things ranging from 20KHz to 100KHz. So higher carrier frequency IR recievers are clearly not sold under similar names and descriptions to the standard type originating from TV remote technologies. What are they descriebd as, what should I be looking for, has anyone an example part number or two? I'm aware that some of the products might be described as IRDA components, but even that seems to be focused on 115KHz, and those IRDA transciever things look from the datasheets like they are just an LED and photodiode in a package together without any filtring and gain circuits built in. Their datasheets don't have any of the kind of mentions of filtering and waveforms that the TSOP38238 and related low frequency devices do.
Thanks