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FORMAT: Linear Video |
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LVR |
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| Nearly all the video tape formats displayed in the museum are helical scan systems, with the read/write heads mounted on a spinning disc to get adequate head-to-tape speed. The only linear formats were the Wesgrove and TelCan systems from way back in the 1960's.
But even as late as the eighties, some manufacturers were still trying to develop linear home equipment. BASF and Toshiba were both experimenting with Linear Video Recording, or LVR, which would use stationary heads for greatly reduced complexity. This would naturally make the machines cheaper to make, as well as lighter, smaller and probably more reliable than their helical cousins. |
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| To get around the problem of short playing time, due to the high tape speed necessary for linear recording,
both systems used multiple tracks across the width of the tape. BASF used 8mm tape with 72 parallel tracks, dropping to
the next track and reversing direction at each end of the tape. 600 metres of tape in a cartridge a little smaller than a CD case (but twice as thick) gave up to three hours of recording at a tape speed 4m/s. This compares to head-to-tape speeds of 5.8m/s for Betamax, and 4.8m/s for VHS.
The cartridge contained a single spool of tape, with the take-up reel inside the machine. This meant the the tape would have to be rewound before it could be removed, but unlike a "normal" cartridge system, the multi-track approach allowed you to skip quickly to any part of the recording - or at least, to the start of any track, which would be within 2.5 minutes of any point. |
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| Toshiba's system, in contrast, used an endless loop of half-inch tape - 100 metres, which took just 17
seconds to go through the machine (at 6 m/s) but had 220 tracks across it to give an hour of playback. This was later increased to 300 tracks, with 24.5 seconds of tape, to give over two hours.
The track change occurred when the tape "join" passed the heads, just as with an 8-track audio cartridge, and took 22ms. |
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| Both systems were demonstrated at the Berlin Radio & TV Show in 1979, and Toshiba even got as far as announcing a launch date of September 1980 and a "target price" of £250 [2005: £715]. But that seems to be the last that was ever heard of either system; Toshiba went on to back Betamax, and BASF stayed in the tape business, rather than hardware.
Personally I think it's a pity, it was a nice idea. I suspect that the problem was in making a noiseless and reliable track-change, and (particularly in the case of Toshiba's endless loop system) wear-and-tear on the tape. And, by the time they were readying for launch, VHS and Beta were becoming well-established, so perhaps it was a simple marketing decision. |
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PXL
Another linear system which actually did make it to market was the audio-cassette based PXL system - affectionately known as the "KiddieCorder". This amazing system now has it's own exhibit, in Room 10 |
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