Technology of television
Elements of a television system
An image source. This is the electrical signal that represents a visual image, and may be from a professional video camera in the case of live television, a video tape recorder for playback of recorded images, or telecine with a flying spot scanner for the transfer of motion pictures to video). A sound source. This is an electrical signal from a microphone or from the audio output of a video tape recorder. A transmitter, which generates radio signals (radio waves) and encodes them with picture and sound information. A television antenna coupled to the output of the transmitter for broadcasting the encoded signals. A television antenna to receive the broadcast signals. A receiver (also called a tuner), which decodes the picture and sound information from the broadcast signals, and whose input is coupled to the antenna of the television set. A display device, which turns the electrical signals into visual images. An audio amplifier and loudspeaker, which turns electrical signals into sound waves (speech, music, and other sounds) to accompany the images. Practical television systems include equipment for selecting different image sources, mixing images from several sources at once, insertion of pre-recorded video signals, synchronizing signals from many sources, and direct image generation by computer for such purposes as station identification. The facility for housing such equipment, as well as providing space for stages, sets, offices, etc., is called a television studio, and may be located many miles from the transmitter. Communication from the studio to the transmitter is accomplished via a dedicated cable or radio system.
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