FMHD-1 Operator’s Manual
BELAR ELECTRONICS LABORATORY, INC.
Page 9
Studio Installation Procedure:
1.
Mount the
FMHD-1
in a rack with the required AC power and sufficient cooling.
2.
Set up an appropriate receiving antenna with a clear path to the transmitter. Run a 75Ω lead-in with an
F connector to the rack.
3.
Apply power to the
FMHD-1
.
4.
After the Main Tuning Screen appears, tune the
FMHD-1
to the carrier frequency using the encoder knob.
(Control of the
FMHD-1
and use of the encoder knob are described under “Front Panel Operation” on page
11.)
5.
Bring up the RF Popup Menu on the display by depressing the encoder knob. Enter the “Input Select”
sub-menu and set the input to “Antenna”.
6.
Connect the antenna lead-in to the
FMHD-1 “Antenna” F connector
. If the RF level bargraph on the
Main tuning Screen indicates red, immediately remove the antenna feed and place a 75-
Ω attenuator in the
antenna feed line.
7.
Adjust the external
attenuator to obtain an RF Level bargraph reading in the green.”
8.
Connect any desired
FMHD-1
outputs and continue with the
FMHD-1
setup.
3.5
FMHD-1 Output Connections
All electrical connections to the
FMHD-1
are made through connectors on the rear panel of the unit.
Refer to the photograph of the FMHD-1 rear-panel on page 3 of the booklet
FMHD-1 Guide to
Operations
for the locations of the various connectors.
3.5.1
Audio Outputs
There are eight XLR output connectors carrying the monitor audio and test signals in analog form and
three BNC output connectors providing six signals in the serial digital AES/EBU format. (At initial
power-up, the monitor signals are automatically assigned to the outputs according to the defaults listed in
Table 2: “
FMHD-1
Popup Menu Map,” under “Settings: Outputs”.)
3.5.2
XLR Connections (analog channels 1–8)
Analog output channels 1 through 8 employ active-balanced output circuitry designed to drive 600
Ω
differential loads via XLR-type connectors. The outputs are chassis-mounted XLR plugs, with the
following connections:
Pin 1
Circuit ground and shield
Pin 2
Negative polarity output
Pin 3
Positive polarity output
Positive polarity has the sense that modulation raising the carrier or sub-carrier frequency results in an
increasing output voltage at pin 3 of the connector. The output level is +10dBm into 600
Ω, or 2.45Vrms
,
for 100% modulation.
These lines will drive up to 500 feet (150m) of shielded twisted-pair broadcast cable, such as Belden™
8451,
when terminated in 600Ω.
If an XLR output is used to drive an unbalanced load, the output connection of the alternate polarity
(either pin 2 or pin 3 of the XLR chassis connector) must be connected to pin 1 of that same connector
with a short lead.
(Note that while the two outputs of the active-balanced pair may be used to drive separate unbalanced
loads, imperfect loading of the line-balancing mechanism of the circuit results in interaction between the
two outputs. Independently loading the two signal connections may jeopardize signal integrity.)
Summary of Contents for FMHD-1
Page 1: ...BELAR Broadcast Equipment FMHD 1 FM HD RADIO MONITOR ...
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Page 8: ...FMHD 1 Operator s Manual ...
Page 55: ...FMHD 1 Operator s Manual BELAR ELECTRONICS LABORATORY INC Page 47 ...
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