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Type B videotape 

Type B video tape
Type B video tape

1 inch type B VTR (designated Type B by SMPTE) is an open-reel videotape format developed by the Bosch Fernseh devision of Bosch in Germany in 1976. It never saw much success compared to the competing 1" Type C format, due to the format requiring an optional, and costly, digital framestore in addition to the normal analog timebase corrector to do any "trick-play" operations such as slow motion/variable-speed playback, frame step play, and visible shuttle functions.

This was because, unlike 1 inch type C which recorded one field per helical scan track on the tape, Type B segmented each field to 5 or 6 tracks per field according to whether it was a 525 (NTSC) or 625 (PAL) line machine.

The tape speed allowed 96 minutes on a large reel (later 120 minutes), and used 2 record/playback (R/P) heads on the drum rotating at 9000 RPM with a 190 degree wrap around a very small head drum, recording 52 video lines per head segment. Video is recorded on an FM signal with a bandwidth of 5.5 MHz. Three longitudinal audio tracks are recorded on the tape as well: two audio and one Linear timecode (LTC) track.

The picture quality was excellent, and standard R/P machines, digital frame store machines, reel-to-reel portables, random access cart machines (for playback of short-form video material such as television commercials), and portable cart versions were marketed.

Contents

Models introduced

  • BCN40 (1976, record unit with no TBC playback)
  • BCN50 (1976, recorder with TBC playback)
  • BCN20 (1976, portable with no TBC playback)
  • BCWQ ("L" Unit for BCN20/21, added TBC playback to the portable units)
  • Effects control option for digital framestore, for freeze frame, quad spilt and mirror effects (early digital Special effects).
  • BNC51 (recorder with TBC playback, optional Slow motion and visible shuttle)
  • BCN5 (26 1/2 pound, portable cart recorder)
  • BCN100 (random access cart machine, up to 16 hours rec/playback)
  • BCN52 (recorder with Digital TBC playback, with slow motion & visible shuttle)
  • BCN21 (lightweight reel to reel portable with no TBC playback, first composite VTR)

RCA also sold the BCN50 as an HR-400.

Special BCN units

  • Image Transform in Universal City used specially modified BCNs to record 24-frame video also, but for their "Image Vision" system. The BCN would record and play back 24-frame video at 10 MHz bandwidth, with twice the standard 525-line NTSC resolution. To record this the headwheel and capstan ran at twice normal speed. Modified 24fps 10 MHz Bosch Fernseh KCK-40 professional video cameras were used on the set. This was a custom pre-HDTV video system. This recording could be recorded as film out on a modified 3M Electron Beam Recorder (EBR) for film. Image Transform had modified other gear for this process. At its peak, this system was used to make "Monty Python Live at the Hollywood Bowl" in 1982. This was the first major use of early electronic cinema technology (using wideband high-resolution analog video technology, predating IT-based DI (digital intermediate) post production for film nowadays) using a film recorder for Film out.
  • Bell and Howell (later Rank Video Services) used special BCNs for mass VHS duplication. These specially-modified BCN VTRs could play back movies at two times the normal speed. In addition, the sync signals were also output at two times speed as well. For proper playback, the headwheel and capstan also ran at twice normal speed. Specially modified VHS recorders could record this video. In doing this, the duplication plant could output twice the product than normal videocassette duplicating systems.
  • Bell and Howell's Data Tape division in Pasadena, California modified BCNs to record high speed data for instrumentation purposes. These instrumentation recordings were mostly used by US government agencies, such as for NASA on the Space Shuttle. This unit could record data from up to 800 sensors.
  • Some users modified BCNs to fit 2-hour reels of tape on the BCN, so complete 2-hour movies could fit on one reel of tape. Bosch later made this a factory option, and was designated as BCN LP.
  • Bosch also offered SLP BCN, a "long-play" variant of the format. It moved the tape at half speed so that up to 4 hours could be recorded on reel. This was mostly used for time zone tape delay by television networks.
  • One of the first Digital SDTV VTRs was a non-production prototype BCN deck that could record and play back early type of CCIR 601 digital signals. These two units paved the way for the later SMPTE D1 VTR standard.

BCN 51 VTR

Some BCN users

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See also

External links
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