Orban OPTIMOD-FM 8700, Operating Manual

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OPTIMOD-FM DIGITAL INSTALLATION
2-15

The
L
OUDNESS
L
EVEL
meters, which uses the ITU-R BS.1770-3 algorithm, indi-
cates the relative loudness level at the output of the digital and analog radio
processing chains. The reference level for the analog and digital processing
chains are set independently. The loudness level for the analog radio chain is
shown as a number at the bottom of the main meter screen on the 8700i
unit; it is shown as a meter on PC Remote. See
BS.1770 Loudness Level on
page 1-24.

The
L
OUDNESS
GR
meters indicate the amount of gain reduction produced
by the BS.1770 Safety Limiters in the digital and analog radio processing
chains.

M
ULTIPLEX
P
OWER
GR / BS.1770 GR
METER
uses a two-color display to indi-
cate the action of the ITU Multiplex Power controller and the BS.1770 safety
limiter in the analog radio processing chain. It shows how much the Multi-
plex Power Controller and BS.1770 Safety Limiter have reduced the clipper
drive, reducing the average power in the processed audio. The BS.1770 gain
reduction is shown in cyan and the multiplex power gain reduction is shown
in dark blue.
This meter, labeled “PWR,” is displayed on the 8700i’s color LCD. It al-
ways appears when the Two-Band Structure is active. When the Five-
Band Structure is active, the meter only appears when the Multiplex
Power Controller is turned on.
External AGC Installation (optional)
[Skip this section if you are not using an external AGC ahead of the 8700i. Continue
with “Quick Setup” below.]

As of this writing, the currently manufactured Orban products that can be used
as external AGCs are Optimod-PC 1101/1101e, Optimod PCn 1600, and Optimod
6300. Their manuals contain instructions on how to use them in this application.
They are the preferred choices because their AGCs are identical to the AGC in
the 8700i.

Discontinued Orban products usable as external AGCs include the 8200ST, 464A
“Co-Operator,” 8100AST, and Optimod-PC1100. In this manual, we do not pro-
vide systematic instructions for setting up all of these older products, although it
should be easy to extrapolate from the instructions we provide for the 8200ST
below.

If you are using an Orban 8100AST (or 8100A/ST) external AGC, refer to page 1-
19.
If you are using an Orban 8200ST external AGC:
If the STL uses preemphasis, its input preemphasis filter will probably introduce
overshoots that will increase peak modulation without any increase in average
modulation. We therefore strongly recommend that the STL transmitter’s