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Path: utzoo!linus!decvax!decwrl!lionel@eiffel.DEC (Steve Lionel)
From: lionel@eiffel.DEC (Steve Lionel)
Newsgroups: net.video
Subject: Stereo confusion
Message-ID: <3712@decwrl.UUCP>
Date: Sat, 17-Aug-85 00:28:11 EDT
Article-I.D.: decwrl.3712
Posted: Sat Aug 17 00:28:11 1985
Date-Received: Mon, 19-Aug-85 21:46:03 EDT
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Organization: Digital Equipment Corporation
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Paul Kemp chided me for some inaccuracies in my item about Hi-Fi VCRs.
I don't think I was as far off as Paul thinks.

1.  On the item of "forwards and backwards compatibility", I simply meant
    that Beta Hi-Fi tapes could be played on non-Hi-Fi units, and
    vice versa.  What is important here is that Beta Hi-Fi machines also
    record the linear mono track, and that the Hi-Fi signal does not confuse
    a non-Hi-Fi Beta VCR.  Much the same holds for VHS Hi-Fi, by the way,
    except for the problems noted later about the stereo tracks.

2.  I know enough about AFM recording to know that AFM has nothing to
    do with the way that the information is put onto the tape in VHS Hi-Fi.
    The "depth multiplexing" works in part because the video signal is
    at much higher frequencies than the audio signal, and thus doesn't
    penetrate as far into the magnetic coating as does the audio signal.
    As I said in my first note, the azimuth angles are also different so
    as to minimize interference.  The term AFM simply means that the
    audio is frequency modulated.

3.  Some newer VHS Hi-Fi VCRs, such as Panasonic's latest model 1740,
    do NOT play or record the linear track in stereo.  I don't understand
    this cheapness either, but there it is.

4.  As for my comment on JVC coming up with something to match SuperBeta,
    and Paul relating JVC's noise reduction techniques, I stand by
    my comment.  In that item in Video that Paul quoted, it said that
    JVC admits that "high-band VHS" (which would be the same technique as
    SuperBeta) isn't coming before 1987.  The circuit enhancements JVC
    is adding does not significantly increase the information in the picture,
    but tends to fool you into thinking the picture is sharper - that's
    the "white clipping" part.  Note that the VHS camp definitely has
    said that they don't want these enhancements called "SuperVHS". (Maybe
    because it would make it painfully obvious that VHS is always in
    a trailing technological position relative to Beta.)  As a matter of
    interest, several people I know are replacing their VHS decks with
    a new SuperBeta - the difference is too real to be ignored.

					Steve Lionel