Orban OPTIMOD-FM 8600Si, Operating Manual

Page: 80 / 356

2-24
INSTALLATION ORBAN MODEL
tals 20%, you can set the total modulation to 110% (
±
82.5 kHz deviation). The
8600Si has the ability to reduce audio modulation to compensate for subcarriers.
The advantage of using the modulation reduction function is that the pilot injec-
tion stays constant when the audio modulation is reduced. However, using the
modulation reduction function is slightly inconvenient because it requires pro-
gramming and activating at least one 8600Si GPI input.
If you have the same sub-
carrier injection at all times , a more convenient alternative is to set the desired
modulation level by using the
C
OMPOSITE
L
EVEL
control(s). Then turn up the pilot
injection control until the injection equals 9% modulation.
If you wish to use the modulation reduction function anyway:
A) Navigate to Setup
>
Next
> M
ODULATN
R
EDUCTN .
B) Hold down the appropriate
M
OD
. R
EDUCTION button and turn the knob to set
the amount of modulation reduction produced by the
M
OD
. R
EDUCTION
1
and
M
OD
. R
EDUCTION
2
functions.
You can program these to be activated via any rear-panel GPI input or by
the 8600Si’s clock-based automation. (See
Remote Control Interface Pro-
gramming starting on page 2-45 and Automation starting on page 2-39.)
When both modulation reduction functions are active, the modulation
reduction is the sum of their settings.
To comply with FCC Rules, set the modulation reduction to one-half the
injection of the associated subcarrier. For example, if your subcarrier in-
jection totals 20% from two 10% subcarriers, set
M
ODULATION
R
EDUCTION
1
TO
“5%” and
M
ODULATION
R
EDUCTION
2
to 5%. This will reduce your audio
modulation to 90% (100% – 5% – 5%). When you add back the 20%
modulation due to the subcarriers, you get the required 110% total mod-
ulation.
The Modulation Reduction function is active as long as signal is applied
to its associated GPI input.
C) Program the GPI input(s).
a) Navigate to Setup
>
Next
> N
ETWORK
&R
EMOTE
> R
EMOTE
I
NTERFACE .
b) Using the Next button, scroll the screen until you see the button
corresponding to the GPI terminal you wish to program.
c) Hold down this button and turn the knob until you see
M
OD
. R
EDUCTION
1
or
M
OD
. R
EDUCTION
2
as desired.
To program clock-based automation to activate modulation reduction, follow
the instructions found in “Using Clock-Based Automation” on page 2-39.
3. Program Silence Sense (optional)
You can program the 8600Si to switch automatically from its digital input to its
analog inputs if the
I
NPUT
S
OURCE
is set to
D
IGITAL
and the signal at the digital in-
put falls silent. Conversely, you can also program the 8600Si to switch automati-
cally from its analog inputs to its digital input if the
I
NPUT
S
OURCE
is set to
A
NALOG
and the signal at the analog input falls silent