Television has four important stages from a technical point of view: (1) conversion of an optical image created by an imaging device such as a camera into electrical signals, (2) re-conversion of the electrical signals into an optical image for viewing at the receiver, (3) amplification of the converted electrical signals, and (4) synchronization of the scanning throughout the first imaging segmentation stage and the second image reconstruction stage.
(From TV Kotohajime by Kenjiro Takayanagi, published in 1986, Yuhikaku Publishing)