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Posted by Gary Eickmeier on 11/22/05 14:07
Harry Kiri wrote:
> "Harry Kiri" <no_spam@no_spam.com> wrote in message
> news:437d11c4$0$22520$5a62ac22@per-qv1-newsreader-01.iinet.net.au...
>
>
>>On the other hand, at LP the drum would have to rotate at a
>>lower speed too, so the voltages induced in the heads should
>>theoretically be significantly lower, (flux change/unit time
>
> reduces),
>
> <snip>
>
>>Regards,
>>Hughy
>
>
>
> No one picked up my deliberate mistake? :-)
>
> Thinking further, a head rotation speed change would be undesirable,
> the head rpm (probably) should remain constant at either LP or SP.
Right - the head rotates at the same speed whether in SP or LP.
>
> Maybe they use FSK to commit the data to tape? Perhaps 1 frequency
> pair for video and 1 for audio? For arguments sake, using, say, a sub
> carrier of 1MHz to represent a 0 and 1.001 MHz for a 1. A tape that
> was travelling slightly off spec, might shift one or both audio FSK
> frequencys outside the filter B/W. Nah ... that's not right either.
> Head RPM would be the critical factor in any shift in FSK outside B/W,
> not tape speed.
>
> The system probably isn't as uncomplicated as a couple of FSK's, Sony
> et al have probably developed such clever recording electronics that
> they'd make *our* heads spin faster than the cameras trying to follow
> their method :-)
>
> None of this conjecture explains the intermittent 1 or 2 frame audio
> dropout that the odd VX2K seems to develop after a while.
Must have something to do with head wrap or tape path tension, such as
if the little reels snag up for a split second and don't run smoothly.
But why doesn't the video also mistrack? More data?
>
> Any one else experience this intermittent dropout?
I wish someone would answer this. I am very grateful for your testimony.
Maybe it is a common problem that the techs can fix.
Gary Eickmeier
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