Television

Television (TV) is a technology for transmitting moving images and sound using radio waves, cable, satellite, or the internet. The term also refers to the receiver device used in homes and to the broadcast facilities that produce programs.

The system works by dividing an image into small units (pixels) and lines. A camera converts the image into electrical signals; a transmitter sends these; and the receiver reconstructs the image by displaying many pictures in quick succession instead of a single static image, creating the appearance of continuous motion to the eye.

Brief history

In the early 20th century, mechanical television systems were developed, relying on rotating discs with holes. These were later replaced by electronic systems using cathode ray tubes (CRT), which became the standard through most of the 20th century. Regular television broadcasting began in Europe and North America in the 1930s and 1940s, then spread to the rest of the world.

Color and transmission standards

Color television uses three primary colors—red, green, and blue—which combine to produce other colors. Various analog transmission standards existed, such as NTSC, PAL, and SECAM, used in different regions. Since the late 20th century, digital transmission has replaced analog, bringing higher quality (HD, then 4K) and reduced power consumption and bandwidth use.

Transmission methods

Terrestrial broadcasting uses antennas on the ground. Cable systems use cables connected to homes. Satellite covers wide areas and is used by many international channels serving Somalia. The latest method is internet transmission (IPTV and streaming services), which gives viewers on-demand access at any time.

Social role

Television plays a significant role in news, education, and entertainment. Government, commercial, and community organizations use it. The laws of many countries require broadcast licenses, and there are regulatory bodies overseeing content and spectrum allocation.