I have a sinusoidal signal at 50 Hz, that varies in amplitude, with no offset. The amplitude goes from 0 to 5 V (peak to peak), and the amplitude contains all the information I need. This signal will change abruptly (in amplitude) but not very frequently, by that I mean for example that it could be at 2Vpp for an hour and then suddenly change to 3Vpp.
What I want to do is transmit that information using FM. For that to work I will need to transform the signal into something which gives me the same information but now related to it's frequency. For example map the 0 to 5 V range into some frequency range so then I can modulate using a VCO. I would also need to demodulate this at the receptor, and will probably need to remap from frequency to voltage ater the signal is received. This I don't know how to do, so I'm asking for help here.
I don't know if I explained myself correctly, so I'll edit my question if needed. I know that FM may not be the best way to go here, but I have all the components I would need and I don't have the money to buy for some other option.