I have a "panel" connected to my main circuit board via conducting lines. I intend to transmit small voltages (of the order of say 0.125 volts) from my main board to the panel.
For my model this is no problem, since i would not be transmitting over long distances, the distance of separation will be << 1m. If the circuit will be expanded for real-world implementation the conducting line will be much longer, something of the range of > 3m (perhaps), or even more.
So I thought a form of line driver might be necessary if these small transmitted voltages won't get significantly attenuated. I thought of making them ride upon a higher voltage, 5v, where I'll kind of "demodulate" them at the receiving panel.
I thought of using an opamp adder (summing the small voltage with 5V) at the transmitter (cct board) and using a subtractor (subtracting 5v form 5v+Vsmall) at the receiving panel to extract the original small voltage.
Is this the method usually used? How brilliant is this approach?