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词条 video tape recorder
释义
video tape recorder
electronics
also called Video Recorder,
electromechanical device that records and reproduces an electronic signal containing audio and video information onto and from magnetic tape. It is commonly used for recording television productions that are intended for rebroadcasting to mass audiences. There are two types of video tape units: the transverse, or quad, and the helical.
The transverse unit uses four heads rotating on an axis perpendicular to the direction of 2-inch (5-centimetre) tape. The transverse format achieves a 1,500-inch-per-minute head-to-tape speed necessary for high picture quality. For broadcast industry needs, an audio track, control track, and cue track are added longitudinally. These units follow the standards of the North American Television Standards Commission—i.e., the electron beam sweeps 525 horizontal lines at 60 cycles per second.
The helical unit, designed for home and amateur use, uses half- or three-quarter-inch tape traveling around a drum in the form of a helix. There are various forms of these recorders: the playback deck can play back recorded programs but cannot record or erase; the video-record deck can record directly from a camera but cannot record off-the-air programs; the TV-record deck has an antenna and tuner for recording off-the-air programs. Portable reel-to-reel or cassette recorders are also produced. See also magnetic recording.
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更新时间:2025/2/19 16:50:44