Signal Modulation
Composite video can easily be directed to any broadcast channel simply by modulating the proper RF carrier frequency with it. Most home analog video equipment record a signal in (roughly) composite format: LaserDiscs store a true composite signal, while consumer videotape formats (including VHS and Betamax) and lesser commercial and industrial tape formats (including U-Matic) use modified composite signals (generally known as "color-under"). On playback, these devices often give the user the option to output the baseband signal or to modulate it onto a VHF or UHF frequency compatible with a TV tuner (i.e., appearing on a selected TV channel). The professional television production uncompressed digital video videocassette format known as D-2 (video) directly records and reproduces standard NTSC composite video signals, using PCM encoding of the analog signal on the magnetic tape.
Read more about this topic: Composite Video
Famous quotes containing the words signal and/or modulation:
“Change begets change. Nothing propagates so fast. If a man habituated to a narrow circle of cares and pleasures, out of which he seldom travels, step beyond it, though for never so brief a space, his departure from the monotonous scene on which he has been an actor of importance would seem to be the signal for instant confusion.... The mine which Time has slowly dug beneath familiar objects is sprung in an instant; and what was rock before, becomes but sand and dust.”
—Charles Dickens (1812–1870)
“Every accent, every emphasis, every modulation of voice, was so perfectly well turned and well placed, that, without being interested in the subject, one could not help being pleased with the discourse; a pleasure of much the same kind with that received from an excellent piece of music. This is an advantage itinerant preachers have over those who are stationary, as the latter can not well improve their delivery of a sermon by so many rehearsals.”
—Benjamin Franklin (1706–1790)