NetNews Usenet Archive 1992 #31/NN_1992_31.iso/spool/rec/video/15227

Internet Message Format | 1992-12-30 | 1.2 KB

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From: [e-mail] (Jan Bielawski)
Newsgroups: rec.video
Subject: Re: digital video camcorders?
Message-ID: <[e-mail]>
Date: 30 Dec 92 21:24:59 GMT
References: <[e-mail]>
Organization: Computervision, San Diego, CA
Lines: 18

In article <[e-mail]> [e-mail] (John Grant) writes:
<Why are camcorders (8mm,vhs-c,etc) still analogue?  If DAT is so great,
<why aren't there any camcorders recording digitally (DAT or similar)?
<Doesn't DAT have enough bandwidth for video?

    No, it's nowhere near.  The highest frequency needed for audio
is about 20 kHz.  Even for the worst quality video -- namely, VHS --
you need, say, 3.25 MHz and if you want something on the order of Hi8,
you'd want something around 5 MHz.  So you need a sampling frequency
of at least 6.5 MHz instead of DAT's 48 kHz.  That's more than 135 times
as fast for a resolution inferior to that of 8mm.  I doubt this could be
done on a DAT-sized (or 8mm-sized) drum.  What's the drum diameter
of the D3?

    Jan Bielawski
    Computervision, San Diego
    [e-mail]