Orban 8182A Operating Manual page 40

In
all
cases,
it is
assumed
that
the
STL
is
a pair of
land-lines,
a pair of
microwave
STL's,
or
a
PCM
link.
There
are four
steps:
1)
Stereo Or Mono
Installation: Adjust
the operating controls
on
the Accessory
Chassis
as follows:
Proof/Operate
Switch:
OPERATE
Loudness
Controller:
OFF
L
and
R
Input Attenuators:
0
Clipping:
+2
Release Time:
10
Bass Coupling:
10
Gate
Threshold:
0
HF
Limiting:
10
2)
Stereo
Or Mono
Installation:
Connect
an audio
oscillator to the
LEFT INPUT
of the Accessory
Chassis. Set
its
frequency
to
1kHz, and
its
output
level to
produce
"OdB" +3dB
as indicated
on the Accessory
Chassis
TOTAL MASTER
G/R
meter.
[This
establishes a
standard
level at the output of the
Accessory
Chassis
of
1.17Vrms (+3.6dBm)
+0.5dB
when
its
OUTPUT ATTEN
is
fully clockwise and
when
its
balanced output
is
loaded by 600 ohms.
This level
is
3.4dB below
nominal 100%
modulation
in a 75us preemphasis system, although compressor
overshoots
will
produce peaks
substantially above
this level.]
If
the
STL
is
un-preemphasized,
adjust
the Accessory
Chassis
OUTPUT
ATTEN
until the
STL
is
modulated 8dB below
its
nominal
100%
modulation
level.
In the case
of a
microwave STL,
refer to the modulation meter
on
the
STL
transmitter.
In
the case of a U.S.A.-standard
land-line requiring a nominal
drive
level
of
+8dBm,
simply
turn the Accessory
Chassis
OUTPUT ATTEN
fully clockwise.
If
the
STL
is
preemphasized
at
50
or 75us, adjust the Accessory
Chassis
OUTPUT ATTEN
until the
STL
is
modulated 12dB below
its
nominal
100%
modulation
level.
Stereo
Installation Only: Repeat
Step
(2)
for the
RIGHT CHANNEL
of the
Accessory
Chassis, using the
RIGHT
CHANNEL
STL.
Mono
Installation Only:
If
you have two STL's
for redundancy, repeat Step
(2)
using
the
RIGHT
CHANNEL
of the
Accessory
Chassis and
the redundant
STL.
If
you have
only one STL, proceed
to the next
step.
3.a)
Stereo
Installation Only: Reconnect
the oscillator
to the
LEFT
Accessory
Chassis
input,
and
drive
it
with
a
1kHz
tone
at a level
which produces
a "0"
reading on the
TOTAL MASTER
G/R
meter. Connect
the output
of the
LEFT
STL
receiver
to the
LEFT INPUT
of the
OPTIMOD-TV
Main
Chassis. Place
the
VU
meter
FUNCTION
switch
in
L
COMPR
OUT.
Adjust the
LEFT INPUT
ATTEN
on the
OPTIMOD-TV
Main
Chassis
to
make
the
VU
meter
read
100%.
(NOTE:
Jumper
Cards
j?3TX and //4TX
are shipped with 20dB
pads ahead
of
the input amplifiers.
If
the readings
in
the L
COMPR
OUT
position
of the
Main
Chassis meter
are too
low with
the
INPUT ATTEN
fully
CW
and
the
input pads
are strapped
for
20dB
attenuation, restrap
them
for
0c©
attenuation. This
is
done by moving
the jumpers on Cards
#3TX
and
#4TX
according
to Fig. 3-3. The
cards and subpanel are then replaced.
4-2