Using 2 CMOS bilateral switches in what is essentially a 2 channel multiplexer. As you can see the signal inputs may be analog or digital but the control input must be digital and have high and low values of Vdd and Vss respectively.
The voltage range of the input signals must also be between the supply rails in order to be passed through undistorted. If one wishes to handle signals without having to add the DC bias, Vss can instead be made negative WRT ground however, the low control signal voltage would similarly need to extend to the negative rail. *Updated to add split supply version.*
