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HARRIS
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WARNING: Disconnect and lockout AC primary power prior to servicing
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As in the visual signal path, in higher-powered systems, it may become necessary to feed
parallel signal paths through one or more phase and gain modules. These modules allow the
gain and phase of each path to be trimmed, so that the proper phase and amplitude
relationships are obtained at the final combiner input.
1.2.10.5 Aural RF Amplifier Chains
The aural RF amplifier chains vary in complexity depending on visual peak power output,
10% or 20% aural power, and single or parallel paths. The following configurations are
used in the various transmitter models:
10 kW and 15 kW Systems, 10% Aural (normal sound power)
In these systems, the aural AGC output feeds a driver module, whose output is split in
a two-way splitter and sent to two PA modules. The PA module outputs are
recombined in a two-way combiner, whose output passes through a harmonic filter
before reaching the optional notch or hybrid diplexer.
The drive signal is then split four ways in a four-way splitter, whose outputs drive
four parallel PA modules. The outputs are recombined in a four-way combiner and
passed through a harmonic filter before being sent to the optional diplexer.
20 kW Systems, 10% Aural (normal)
The aural AGC module output passes through a phase and gain module. Each of the
two outputs passes to an aural chain in one of the PA cabinets.
Once inside the PA cabinets, the two signals are sent to driver modules. Their outputs
are split using two-way dividers, and the resulting outputs feed an array of four PA
modules. The two PAs in each cabinet feed two-way combiners, and the combiner
outputs feed a 3 dB hybrid used as a final two-way combiner. The resulting signal
passes through a harmonic filter before being sent to the optional diplexer.
30 kW Systems, 10% Aural (normal)
In a high band system, the AGC module output first passes through a preamp. In low-
band systems, the preamp is not necessary.
The resulting output drives a driver module. The driver output is divided in a four-
way divider, and fed to four parallel PA modules. The outputs are recombined in a
four-way combiner, whose output passes through a harmonic filter on its way to the
optional diplexer.
45 kW Systems, 10% Aural (normal)
In a 45 kW low band system, the AGC module output drives a phase and gain
module, whose outputs drive two driver modules. In high band systems, the two
signals each pass through three-way power dividers, whose outputs feed a total of six
aural PA modules. The PA module outputs are recombined using three-way
combiners and a 3 dB quadrature hybrid, whose output passes through a harmonic
filter to the optional diplexer.
