The input transducer converts the sound or image information to be transmitted into an electrical signal.
The output converter restores the processed baseband signal to the original sound or image.
The transmitting device transmits the baseband.
Channel is the channel of signal transmission.
A communication system refers to a system that transmits information through electrical signals (or optical signals), also known as a telecommunication system. A system is usually an organic whole composed of several units with specific functions, interaction and interdependence, and achieves a unified goal. The simplest communication system allows users to send and receive information between two points. In a general communication system, users can communicate with other users in the system through switching equipment.
Wired system: carrier communication system for long-distance telephone communication, using frequency division multiplexing. It consists of carrier telephone terminal equipment, repeaters, transmission lines and auxiliary equipment. Among them, the carrier telephone terminal equipment is the equipment that moves audio signals or other group signals to the line spectrum or inversely transforms the line spectrum transmitted by the other party, and can adapt to the requirements of line transmission; Repeater can compensate the transmission attenuation and its change of the line, and one repeater is installed at regular intervals along the line.