Orban OPTIMOD-FM 8700, Operating Manual

Page: 89 / 390

OPTIMOD-FM DIGITAL INSTALLATION
2-27
Using program material typical of your format, adjust the M
ULTIPLEX
P
OWER
O
FFSET
control so that the BS.1770 Safety Limiter produces about
3 dB of gain reduction on typical program material. This control is part of
the processing preset, so after you have set the control, save the preset as
a User Preset.
You must adjust the M
ULTIPLEX
P
OWER
O
FFSET
control for each processing
preset you plan to use and then save each one as a user preset.
The following material provides detailed instructions on how to set up the 8700i. If
Quick Setup does not fully address your setup needs or if you wish to customize your
system beyond those provided with Quick Setup, then you may need the additional
information in the sections below. You will need this information if you are setting
up a digital radio facility. However, for most users, this material is only for reference,
because Quick Setup has enabled them to set up the 8700i correctly.
Analog and Digital I/O Setup
For the following I/O calibration parameters, use the
Locate
joystick to highlight in-
put/output parameters. When the desired parameter is highlighted, turn the front
panel control knob to adjust the parameter settings as desired.
Analog and digital parameters appear on the same screen. If you are not using a
given input or output, ignore the parameters associated with it.
1. Specify processing preemphasis.
Navigate to the I
NPUT
/
OUTPUT
> U
TILITIES
screen. Use the P
ROCESS
P
REEMPHASIS
control to select the preemphasis (either 75

S or 50

S) used in your country
2. Temporarily set the External AGC mode to “No.”
Navigate to the
I
NPUT
/
OUTPUT
> U
TILITIES
screen and set
E
XTERNAL
AGC
to
N
O
.
If you are using an external AGC, you will restore this setting to Y
ES
after
the setup procedure is complete.
3. Adjust input selector.
A) Navigate back to the
I
NPUT
/
OUTPUT
> I
NPUT
screen.
B) Set the I
NPUT
to A
NALOG
.
4. Adjust Clip Level control.
[0 dBu to +27 dBu] in 0.5 dB steps
This step matches the level at which the 8700i’s A-D (Analog-to-Digital) converter
clips to the absolute maximum peak level that your installation supplies to the
8700i’s analog input.