V-Cord

V-Cord
Media type Magnetic Tape
Encoding NTSC, PAL
Usage Home movies

V-Cord is an analog recording videocassette format developed and released by Sanyo. V-Cord (later referred to as V-Cord I) was released in 1974, and could record 60 minutes on a cassette. V-Cord II, released in 1976, could record 120 minutes on a V-Cord II cassette.

The V-Cord II machines were the first consumer VCRs to offer two recording speeds.

Appearance

The original V-Cord cassette had a large hub and was wound with standard-thickness magnetic tape; V-Cord II used a small hub wound with thin tape, the same thickness later used for VHS-120 and Beta L-750. The cassettes were rectangular; unlike subsequent formats VHS and Betamax, which loaded with the tape facing front on the long side of the cassette, the V-Cord cartridge was loaded sideways with the narrow side serving as the "front" and the tape coming out the "side".

The tape was held in place in the machine by a notch halfway down the right side of the tape, similar to what holds an 8-track tape into its player.

Operation

The earliest machines recorded only in black and white and had no rewind mechanism, like the Cartrivision format of a few years earlier; an external rewinder was used after recording or playing a tape. External rewinders were later used with the VHS and Beta formats, although the machines could rewind tapes; external rewinders were considerably faster than the rewind function.

Recording format

The system had two recording modes: standard mode (STD), and a long-play mode (LP) which sacrificed recording quality for extra capacity. In STD mode both recording and playback heads are used, writing both fields of each interlaced video frame. In long-play mode only a single head is used to record a single field from each video frame, with each field being read twice on playback, in a "skip field" technique.[1][2] The heads scanned the tape in a helical scan fashion [2]

Tape was moved forward at 2.91 inches per second in STD mode, and 1.45 inches per second in LP mode;[1] this gave a recording time of one-hour in standard mode and two hours in long-play mode. Horizontal resolution in color was quoted as 250 lines in advertising materials, stretching to 300 lines in black-and-white, with a video signal-to-noise ratio of 45 dB.[2] Audio response was specified as 80 to 10,000 Hz at -6 dB in STD mode, dropping to 80 to 8,000 Hz in LP mode.[2]

The tape was a half-inch cobalt doped tape with a 550 oersted coercivity. The cassette measured 4  5⁄16" by 6  3⁄16" by 1". Two cassette types were available, a V60 and a V120 whose names matched their recording capacity in LP mode. The cassettes are similar in appearance to eight-track cartridges.

Conventional VHS and Beta formats recorded in a helical scan format, resulting in angled tracks running from the lower edge of the tape to the upper edge some distance down. Unlike these formats, the V-Cord format was closer to the 2-inch quadruplex videotape format used from the inception of video in the late 1950s until 2-inch helical IVC videotape format was introduced twenty years later, in that its tracks ran nearly perpendicular to tape travel.

A portable four-head video recorder, the Sanyo VTC-7100, used a similar format of cassette, but produced incompatible recordings.

V-Cord VCRs

Toshiba KV-4000, KV-4100, and KV-4200; and Sanyo VTC-7300, VTC-8000, and VTC-8200 V-Cord I/II VCR (1976)

References

  1. 1 2 Abramson, Albert (2003). The History of Television, 1942 to 2000. Jefferson, N.C.: McFarland & Co., Publishers. pp. 160, 170–171. ISBN 9780786412204. OCLC 48837571. Retrieved March 27, 2013.
  2. 1 2 3 4 "Sanyo V-Cord II System advertising brochure" (JPEG). LabGuy's World: The History of Video Tape Recorders before Betamax and VHS.

Further reading

This article is issued from Wikipedia - version of the 9/9/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.