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7 . O V U A D J U S T M E N T
lnformation
This adjustment is to keep compatibility between
decks. This is to determine the level of VU meter
so that the tape is magnetized in the 160 PWb/mm
magnetic flux density when OVU input is sup-
plied. Then, the VU meter reading will be OVU
when playing a tape record by 160PWb/mm.
o
When the OVU adjustment is deviated.
a. When the OVU level is adjusted boo low, the
level distortion will increase because the level
approaches close to the satulation point.
b. When the level is too high, S/N will decrease
because level difference between the signal and
hissing noise of tape becomes smaller.
T a p e h i s s n o i s e
Input -----)
F i g - 6 I n p u t a n d O u t p u t c h a r a c t e r i s t i c .
F i g . 9
Adjustment
c .
Connect an AC volt meter to the output ter-
minal (No.15, 16 and Ground) of the Dolby
ass'y.
Apply the signal of 333H2 to INPUT and set
REC, to REC.
Adjust the recording level control so that AC
voltmeter reading become -7.7dBv(472mV).
At this time, Adjust the semi-fixed resistor
(VR-106, VR-206) so that the reading of the
level meter becomes - OVU.
L-ch No.15
VR-106
-7.7dBv(4t2mV) = - 4.7dBv (- 3dBv)
200PWb/mm
differencebetween200Wb/
mm and 160PWb/mm.
a .
b .
1
o.s.c.
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