单词 | TV (TeleVision) |
释义 | TV (TeleVision) From the Greek tele, meaning far off, and visio, meaning seen, and translating literally as seen far off. A system in which series of still images are communicated across a distance. The TV transmitter scans a view by means of a camera, converts light rays into electrical signals used to modulate a carrier, adds audio converted from acoustical to electrical by a microphone, and adds control signals. The receiver uses the electrical signal to modulate and control a display device and speakers that reconstruct the video and audio signals. Broadcast TV is transmitted over the airwaves. Community antenna television (CATV), more commonly known as cable TV, is transmitted over networks of coaxial cable or hybrid fiber/coax (HFC) networks of coax and optical fiber. Analog TV standards include National Television Standards Committee (NTSC), Phase Alternate Line (PAL), and Séquential Couleur Avec Mémoire (SECAM). Digital TV (DTV) standards include high-definition television (HDTV) and standard definition television (SDTV). See also acoustics, audio, broadcast TV, carrier, CATV, coaxial cable, DTV, electricity, HDTV, HFC, light, microphone, NTSC, optical fiber, PAL, receiver, SDTV, SECAM, transmitter, and video. |
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