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Vision Electronic Recording Apparatus (VERA) was an early analog recording videotape format developed from 1952 by the BBC under project manager Dr Peter Axon. In order to record high frequencies, a tape must move rapidly with respect to the recording or playback head. The frequencies used by video signals are so high that the tape/head speed is on the order of several meters per second (tens of feet per second), an order of magnitude faster than professional analog audio tape recording. The BBC solved the problem by using reels of magnetic tape that passed static heads at a speed of . VERA was capable of recording about 15 minutes (e.g. 4,572 meters) of 405-line black-and-white video per reel, and the picture tended to wobble because the synchronizing pulses that keep the picture stable were not recorded accurately enough. In order to cope with 625-line PAL or SECAM colour transmissions VERA would likely have required an even faster, and possibly unfeasible, tape speed. Development began in 1952, but VERA was not perfected until 1958. It was given a live demonstration on-air in Panorama on April 14, 1958; Richard Dimbleby, seated by a clock, talked for a couple of minutes about the new method of vision recording with an instant playback, and then the tape was wound back and replayed. The picture was slightly watery, but reasonably watchable,〔Description from seeing the original transmission. Part of it can be seen on (YouTube ).〕 and of course instant playback was something completely new. However by this time it had already been rendered obsolete by the Ampex quadruplex video recording system. This used wide tapes running at a speed of per second. The rapid tape-to-head speed of quadruplex videotape was achieved by spinning the ''heads'' rapidly on a drum: the system used, with variations, on all video tape systems ever since, as well as DAT. The BBC scrapped VERA and quickly adopted the Ampex system. It has been suggested that the BBC only continued to develop VERA as a bargaining tool, so it would be offered some of the first Ampex machines produced in unstated exchange for abandoning further work on a potential rival. == See also == * Helical scan 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Vision electronic recording apparatus」の詳細全文を読む スポンサード リンク
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