television (TV), Electronic system for transmitting still or moving images and sound to receivers that project a view of the images on a picture tube or screen and recreate the sound. Early versions (1900–20) of the cathode-ray (picture) tube, methods of amplifying an electronic signal, and theoretical formulation of the electronic scanning principle later became the basis of modern TV. RCA demonstrated the first all-electronic TV in 1932. Cable TV systems (introduced in the late 1940s), colour TV (in the 1950s), and recording or playback machines (in the 1980s; see VCR) followed. Digital high-definition (HDTV) systems (1990s) provide sharper, clearer pictures and sound with little interference or other imperfections and have the potential to merge TV functions with those of computers.