Nuoptix Stereo Optical Recording System, Owner'S Manual

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LIGHT VALVE EQUALIZATION
Check to see that film loss EQ dip switches DS1 and DS2 are set to OPEN
(i.e. flat or no equalization). Toggle the recording lamp to OPERATE and set to
nominal current. Rotate the mode switch to the SETUP position and adjust the
SETUP controls for slack spacing meter reading. Advance the mode switch to
the BIAS position and increase the BIAS controls on the front panel for an 8 mil
bias line as indicated on the front panel meter. Advance the mode switch to the
RECORD position and apply a 50% signal at 400Hz. With the DIRECT/P.E.C.
toggle switch in the P.E.C. position increase the MONITOR control for a 0 dbm
level on the monitor output. Carefully sweep the input frequency making sure
that the input level remains constant and adjust the light valve equalization
internal trimpots to achieve a flat response as monitored on the P.E.C. monitor
output. The reduced signal and bias level are used to assure that the light valve
does not clash during the equalization procedure. The 2KHZ, 4KHZ and 6KHZ
are boost and cut filters with midrange being flat. The 8KHZ (R71) is a cut only
filter with CW being flat. The 8KHZ filter has a frequency trim control F8 (R93)
with midrange being around 8.5 KHZ. The Q of this filter is similar to that of the
light valve. Setting the notch frequency of the 8KHZ filter to just above the light
valve resonance frequency, say 9KHZ, results in the most accurate equalization.
The 10KHZ (R74) is a boost only filter with a frequency trim control F10 (R94).
Rotating F10 CW increases the frequency. Increasing the frequency of the
10KHZ filter to near its upper limit yields equalization out to higher frequencies.
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