Q. Explain Frequency-division multiplexing?

Frequency-division multiplexing (FDM) is a technique for data transmission widely used in telephone, radio, and cable TV systems in which the transmission frequency spectrum (i.e., bandwidth) is divided into smaller bands known as subchannels.

Data transmission between two stations can be achieved in either simplex, half-duplex, or full-duplex mode. In a simplexmode,mainly used in radio and TV broadcasts, information travels only in one direction. Thismode is rarely used in data communications. In half-duplexmode, used by radio communications, information may travel in both directions, but only in one direction at a time. The transmitter becomes the receiver and vice versa. In a full-duplex mode, information may travel in both directions simultaneously. This mode, used in telephone systems, adopts two different carrier frequencies.