Orban OPTIMOD 8400 - If You Are Using an Orban 4000 Transmission Limiter

OPTIMOD-FM INSTALLATION
2-19
C) Adjust the METER CAL controls on the 464A so that the 0 dB segment on the
464A’s
PEAK OUTPUT LEVEL meter just illuminates on program peaks.
D) Adjust the OUTPUT ATTEN controls to drive the STL to 100% modulation on pro-
gram peaks, as shown on its modulation indicator.
4. Set 464A’s controls for normal operation with program material.
A) Set both channels of the 464A controls as follows:
METER CAL Do not change
HF LIMIT PRE-EMPHASIS Do not change
OUTPUT ATTEN Do not change
GATE THRESH 5
RELEASE TIME 5
REL SHAPE SOFT
LEVEL ON
COMPR OFF
HF LIMIT OPERATE
SYSTEM OPERATE
POWER ON
MODE DUAL
B)
Feed the 464A either with tone at your system reference/line-up level, or with typi-
cal program material at normal levels.
C) Adjust the L and R INPUT ATTEN controls for the desired amount of gain reduc-
tion—we recommend 5-10 dB.
D) Switch the MODE switch to STEREO.
If you are using an Orban 4000 Transmission Limiter
If the STL uses pre-emphasis, its input pre-emphasis network will probably in-
troduce overshoots that will increase peak modulation without any increase in
average modulation. We therefore strongly recommend that the STL transmit-
ter’s pre-emphasis be defeated (freeing the STL from such potential over-
shoot), and that the 4000 be used to provide the necessary pre-emphasis.
If the STL transmitter’s pre-emphasis cannot be defeated, configure the 4000
for flat output. In this case average modulation levels of the STL may have to
be reduced to accommodate the overshoots.
1. Configure the 4000’s internal jumpers
A) Remove the top and bottom covers to access the main circuit boards.
Note that the 4000 is a two-channel unit and has two boards with identical
jumpers for resetting.
B)
Refer to Fig. 2-6 for jumper locations.