Frequency Division Multiplexing

Frequency division multiplexing (FDM) is a process that allows each signal to travel on its own unique frequency, the individual signals are then modulated by data type and are combined to form a single signal.

Frequency division multiplexing was first employed in the 1930s in telephone systems to combine multiple conversations onto one single line. FDM has taken a backseat to time division multiplexing (TDM) with the emergence of digital telephone systems.