I've seen lots of schematics on the net for receiving signals modulated at around 30-40kHz, but I'm trying to design a system that will work at around the 1Mhz range. I've practically tried the designs at those frequencies, but there seems to be a lot of atenuation at higher frequencies. I've been told this is because the photodiode acts like a cpaacitor when reverse biased, and that capacitor causes attenuation with high frequencies. Is there any way round that?
I know it must be possible because IRDA manages data rates of up to
4Mbps (although using a PPM system). I'm trying to achieve a data rate or atround 500bps, using any standard as I'm designing transmitter and receiver. Any suggestions?