⭐The Modulator :-
Simple FSK modulation implemented using relay. Still, works like IC 4051 MUX/DeMUX
⭐ The Demodulator :-
The output of the FSK modulator is fed to a high order high pass RC filter. The Op-amp is used to provide gain to the output of the filter.
Only the 100 kHz carrier passes through the filter. The output of the central opamp is fed to a rectifier circuit consisting of Diode, Resistor and a capacitor. This again is fed to the last opamp to give the bitwise output.
⭐ Working :-
Here, depending on the data bit (either 1 or 0), the high frequency carrier is transmitted or the low frequency carrier is transmitted, respectively.
⭐ Legend :-
Red : Final Output
Green : Bit input, 1 or 0
Purple : Transmitted signal, either c1(t) or c2(t).
Yellow : Filter Output
