Vision Electronic Recording Apparatus: Difference between revisions
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'''VERA (Vision Electronic Recording Apparatus)''' was an early [[videotape]] format developed by the [[BBC]] beginning in [[1952]]. |
'''VERA (Vision Electronic Recording Apparatus)''' was an early [[videotape]] format developed by the [[BBC]] beginning in [[1952]]. |
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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 tens of [[Foot (unit of length)|feet]] per |
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 [[Foot (unit of length)|feet]] per second), as opposed to 38 or 75 [[centimeters]] (15 or 30 ''[[inch]]es'') per second used by professional analog audio tape recording. The BBC solved the problem by using 20.5" (52cm) reels of tape that were propelled past the static heads at a speed of 200 inches (almost 17 feet, or 5.08 metres) per second. |
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VERA was capable of recording about 15 minutes 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. Ironically, the only VERA recordings that survive are film [[telerecording]]s of the original demonstration. |
VERA was capable of recording about 15 minutes 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. Ironically, the only VERA recordings that survive are film [[telerecording]]s of the original demonstration. |
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Revision as of 05:08, 6 January 2007
VERA (Vision Electronic Recording Apparatus) was an early videotape format developed by the BBC beginning in 1952.
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), as opposed to 38 or 75 centimeters (15 or 30 inches) per second used by professional analog audio tape recording. The BBC solved the problem by using 20.5" (52cm) reels of tape that were propelled past the static heads at a speed of 200 inches (almost 17 feet, or 5.08 metres) per second.
VERA was capable of recording about 15 minutes 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. Ironically, the only VERA recordings that survive are film telerecordings of the original demonstration.
In order to cope with 625-line PAL or SECAM colour transmissions VERA would have required an even faster, and possibly unfeasible, tape speed.
Development began in 1952, but VERA was not perfected until 1958, by which time it had already been rendered obsolete by the Ampex quadruplex video recording system. This used 2" (5 cm)-wide tapes running at a speed of 15" (38cm) per second. The rapid tape-to-head speed 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. (See also: helical scan)
The BBC scrapped VERA and quickly adopted the Ampex system.