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improved SelectaVision has sealed disc "caddies." Slip the caddy into<br />
a player slot and the disc is loaded automatically. This contactfree,<br />
sealed-player approach sharply reduces groove contamination.<br />
Spiral grooves, with four TV frames per revolution, do not permit<br />
freeze-frame and similar features now. These operating features may<br />
go into future step-up models using electronic memories to store<br />
images. Two fast-search buttons, though, let you jump the stylus<br />
forward or back to quickly locate a scene visually. Also, two other<br />
search buttons move the tone arm and display its position as time on<br />
digital readouts. RCA does not plan to include stereo hi-fi capability<br />
on its initial model, slated for nationwide marketing early next<br />
year. The player's simple construction, plus many microcircuits,<br />
should keep RCA's price under $500. Discs will be $15 to $20, depending<br />
on content. RCA's low-cost approach has gained powerful allies:<br />
Zenith and undoubtedly other TV firms will market or make Selecta-<br />
Visions. CBS Inc. will help expand disc titles from 150 to 300 in the<br />
first year. Programs from several film companies range from classics,<br />
musicals, current films, and how-to, to TV series such as "Star Trek"<br />
(10 episodes) and "Victory at Sea" (a 90-minute version), and "Heidi"<br />
and "Hans Brinker" for children.<br />
[Caption of accompanying photo/diagram: Metal-backed diamond stylus<br />
forms electronic circuit to convert minute capacitance variations in<br />
grooves into TV pictures. Compact, microcomputer-controlled player<br />
has viewing window.]<br />
JVC: grooveless capacitance disc<br />
Victor Company of Japan (or JVC here) rolled out a disc system in 1978<br />
that combines the low-cost aspects of SelectaVision with the operating<br />
options--freeze-frame, slow-motion, etc.--of optical machines. Not<br />
only that, JVC included options for a super-hi-fi audio disc. It<br />
calls the whole package its VHD/AHD system (video and audio high density).<br />
Matsushita, Victor's parent firm in Japan, could offer VHD/AHD<br />
through its Panasonic and Quasar subsidiaries. An announcement about<br />
marketing is expected this summer. VHD/AHD hour-per-side discs are<br />
just over 10 inches in diameter and rotate at 900 rpm. Signals are<br />
stored as capacitance variations, produced by minute pits in the conductive<br />
plastic. The stylus rests over several spiral tracks, distributing<br />
pressure and minimzing wear. (Stylus life is 2000 hours,<br />
roughly 10 times RCA's.) But the metal stylus electrode "reads" just<br />
one information track and the tracking signals on either side of it.<br />
These tracking signals keep the stylus on the right path by feeding<br />
current to a coil/magnet combination on the arm, which can move sideways.<br />
The cantilever arm can also be stretched or shortened instantly<br />
to correct for speed variations (time-base errors). Signals sent to<br />
coils can be used to make the stylus replay one frame continuously,<br />
move ahead or back at slow speed, etc. JVC has also demonstrated an<br />
optional random-access unit with a wireless remote control for the<br />
main VHD/AHD player. It has memories and numbered key pads for pre-
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