Orban OPTIMOD 6300 Operating Manual page 65

OPTIMOD 6300 DIGITAL
2. Set 8200ST Output Level with tone.
A) Press the TONE button on the 8200ST.
The TONE lamp should light and the modulation meters should indicate
"0." If they do not, re-strap jumpers JB and JC to "peak." (Refer to Figure
2-3 on page 2-10.)
The 8200ST is now producing a 400Hz sine wave at each output. The
peak level of this tone corresponds to 100% modulation.
B) Adjust the 8200ST's L O
ing driven to 100% modulation.
L O
The and
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ter. If no significant overshoot occurs in the transmitter, the
meter will now give an accurate indication of peak modulation of the
STL.
C) Turn off the tone by pressing the T
If the STL transmitter suffers from bounce or overshoot, you may have to
reduce the
modulation caused by overshoots on certain audio signals.
3. Set controls for normal operation with program material.
The following assumes that a VU meter is used to determine 8200ST line drive
levels with program material.
A) Set the controls as follows:
HF LIMITER.... Set to match the preemphasis of the transmission system
L&R Out ............................................................................... do not change
GATE .................................................................................................... 12:00
RELEASE ............................................................................................... 12:00
VOICE ......................................................................................................OFF
AGC ..........................................................................................................ON
COUPLE ....................................................................................................ON
B) Feed the 8200ST either with tone at your system reference level (0VU), or with
typical program material at normal levels.
C) Adjust the G
If the STL uses preemphasis, its input preemphasis network will probably
introduce overshoots that will increase peak modulation without any in-
crease in average modulation. We therefore strongly recommend that
the STL transmitter's preemphasis be defeated (freeing the STL from such
potential overshoot), and that the 464A be used to provide the necessary
preemphasis.
We recommend 8-15 dB gain reduction for most formats.
If the STL transmitter's preemphasis cannot be defeated, configure the
8200ST for flat output. In this case, average modulation levels of the STL
may have to be reduced to accommodate the overshoots.
and R O
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R O
controls are now correctly calibrated to the transmit-
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L O R O
and control settings to avoid peak over-
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R
AIN EDUCTION control for the desired amount of gain reduction.
controls so that the STL transmitter is be-
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ONE button.
INSTALLATION
MODULATION
2-11