|  | Posted by Harry Kiri on 11/22/05 12:37 
"Harry Kiri" <no_spam@no_spam.com> wrote in messagenews: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.
 
 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.
 
 Any one else experience this intermittent dropout?
 
 Regards,
 
 
 Hughy
 [Back to original message] |