VERA
|
|
VERA (Vision Electronic Recording Apparatus) was an early videotape format developed by the BBC in the 1950s.
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 feet per second, as opposed to 15 or 30 inches (38 or 75cm) 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 video recording system. This used conventional 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 helical scan.
The BBC quietly scrapped VERA and adopted the Ampex system.
External Link:
Picture and background information (http://www.terramedia.co.uk/Chronomedia/picture_pages/bbc_vera.htm)