Broadcast Electronics FX-50 Instruction Manual Download Page 26

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CONNECTION OF COMPOSITE STEREO SIGNAL SOURCES. The FX-50 is equipped with one balanced and one
unbalanced composite input on the rear-panel (COMPOSITE INPUT BAL and UNBAL). The FX-50E is equipped
with a single unbalanced composite input (COMPOSITE INPUT UNBAL). These inputs are for the connection to a
composite stereo source such as a stereo generator or composite STL receiver (refer to Figure 2-1). A front-panel
COMPOSITE TEST IN connector functions in the same manner as the un balanced composite input. A coaxial
cable is provided in the accessory kit for the connections of a composite stereo or SCA signal to the transmitter.
Both the COMPOSITE INPUT UNBAL and BAL receptacles require a level of 3.5V p-p (1.24 VRMS) to modulate
the carrier at ±75 kHz. These jacks may be used entirely independent of each other and will accept frequencies
of less than 1 Hz to 100 kHz. If these inputs are used, the output level on the composite source must be
adjusted to obtain 100% peak modulation as indicated by the modulation display (145% range).
The BAL input is ac coupled at the input and equipped with common mode rejection circuitry. Therefore, the
BAL input must be used if ground loops and hum are present between the exciter and composite source.
CONNECTION OF SCA SIGNAL SOURCES. SCA unbalanced input receptacles SUB-1, SUB-2, and SUB-3 are
provided on the rear-panel. Each input is ac coupled and accepts frequencies from 40 kHz to 100 kHz. An input
of 3.5V P-P (1.24 VRMS) will modulate the FM carrier 10% at ±7.5 kHz. A coaxial cable is provided in the
accessory kit for the connections of a composite stereo or SCA signal to the transmitter.
If the unit is equipped with the FM synchronous booster system, rear-panel receptacle SUB-1 is used as the
input/output connection for a reference frequency.
When using an SCA input, the output level of the source must be adjusted to obtain the desired peak
modulation as indicated by the modulation display (14.5% range). Each input is also compatible with any SCA
generator using a dc coupled input for the transmission of data.
SYNCHRONOUS FM BOOSTER OPTION. The transmitter can be equipped with a synchronous FM booster
system option. The option consists of a: 1) master configuration and 2) slave configuration. The FM booster
system configures a slave booster to be locked to the frequency of the master booster. Typically, the
master/slave booster options are installed at the factory. If the synchronous FM booster option is to be installed
in the field, installation and operating information is provided in the SYNCHRONOUS FM BOOSTER SYSTEM
section of this manual. Refer to the SYNCHRONOUS FM BOOSTER SYSTEM section of this manual and perform
the installation procedures as required.
Refer to Figure 2-1 and connect the external signal inputs and remote control wiring as required. A second
coaxial cable is provided to connect an SCA or composite input to the exciter.

2.4

EXCITER CHECKOUT.

Before proceeding, check the following:

A. Ensure all connections are secure.
B. Ensure primary power is properly programmed.
C. Ensure the chassis ground connection is secure.
D. Ensure all signal inputs are secure.
E. Ensure the RF output is properly connected.
F. Ensure all external cabling is properly dressed and secured.

CAUTION

THE PRIMARY AC POWER USED MUST BE THE SAME
AS DISPLAYED ON THE AC LINE VOLTAGE SELECTOR
CIRCUIT BOARD.