lionel@eludom.DEC (Steve Lionel) (10/12/84)
Some of you may have seen Sony's recent TV and magazine ads which promote
the Beta format, and Sony's Betamax VCRs in particular, as having a sharper
picture than VHS VCRs. I am happy to see this, as it should serve to spread
the word around. My local dealer gave me a copy of a little brochure which
is intended to help the dealer explain to customers just why Beta is better.
While some of this material has been covered (over and over) in this
newsgroup, much of it hasn't, and I think others would find it interesting.
Please remember that I am quoting Sony material, so please don't flame at me.
-----------
Q. Why does the Sony Betamax have a sharper picture?
A. Higher writing speed. Writing speed refers to how fast the video heads
place electronic information (the video program signal) on the moving
magnetic tape that's in the videocasette. A higher writing speed means
more "video information" can be recorded on the tape. The more video
information there is on the tape, the more detailed and sharp the picture
is. Betamax's writing speed is 20% higher than VHS.
Q. How did the Sony Betamax get its higher writing speed?
A. From its larger video head drum. Betamax's video head drum (the part
of the VCR that transfers the video signal to tape) has a diameter
21% larger than the drum on a VHS. With our larger drum, we place more
of that information on the tape to give you a sharper picture.
Q. What else gives the Sony Betamax a sharper picture?
A. Faster tape transport. Betamax video tape moves 14% faster through
the Beta videocasette (in comparable tape speed modes) than VHS tape.
The faster it moves, the more tape is passed by the video heads
during recording. That means more tape surface is used for recording;
and more tape adds up to more details.
Q. Does the Sony Betamax's sharper picture stay sharper?
A. Yes. One reason is the Betamax videocasette recorder uses a simple
U-loading design; VHS has a more complicated M-loading design. In
U-loading, the tape makes fewer turns (totalling 270 degrees) than
M-loading, where the tape makes more turns at sharper angles
(totalling 540 degrees). U-loading places less stress and tension
on the tape; the tape (and the sharper picture) last longer.
Q. So the Sony Betamax sharper picture is caused by better mechanical
design. Anything else?
A. Better electronics. To get finer detail, the video signal processed
by the Betamax has been designed to transmit a wider range of darks
and lights. This range is called detail contrast. It's possible
because of Sony's advanced circuitry that produces a 30% greater
FM deviation in a Betamax than in VHS, which gives Betamax a
sharper picture. The greater FM deviation also helps reduce any
snow or graininess in the picture.
Q. What else gives Sony Betamax a sharper picture?
A. Higher frequencies. Video signals recorded at higher frequencies
produce a sharper picture. Basically, frequency is the number of
times a signal moves from the lowest to the highest level every
second. The AM chroma signal of a Betamax is 9% higher than VHS,
which results in less interference and color noise. The peak white
FM frequency is also 9% higher, which means there is proportionately
less graininess. It all adds up to a sharper picture.
[The brochure also says the following about the ad campaign:]
... it's important for you to know that the campaign is a result of two
independent consumer surveys:
- A market research study that showed picture sharpness
is more important to VCR prospects than the availability
of prerecorded movies.
- A nationwide study that showed more people said the
picture was sharper with Sony Betamax than the top
14 VHS recorders.
----------
Steve Lionel
ARPA: lionel%orphan.DEC@decwrl.ARPA
UUCP: decwrl!dec-rhea!dec-orphan!lionel
MCI: Steve Lionel (177-0623)
Posted: Fri 12-Oct-1984 13:37 EDT
To: NET_VIDEO