User's Manual

Base Radio Modules Chapter 5: Installing the Digital Simulcast Remote Site (10Base-2)
Table 5-1 STR 3000 Rack Modules
Module Description
Breaker panel Provides on/off control and electrical overload protection to each module within the cabinet.
Cavity combiner Acts as a band-pass filter, combines two to six transmit signals and places them on a single antenna
port. The minimum channel spacing of the cavity combiner is 150 kHz.
Triple isolator Allows RF to pass from the power amplifier to the combiner and antenna while redirecting any
reflected energy from the antenna system away from the power amp and into a 50 ohm load.
Receive multicoupler (RMC) Supplies a port that takes the signal from the RX antenna and distributes the appropriate
information to each base radio in its rack.
Base radio Handles the transmit and receive functions for the rack through separate modules.
The cavity combiner, triple-through isolator, and receive multicoupler comprise
the Radio Frequency Distribution System (RFDS).
Base Radio M
odules
The base radio consists of different modules that handle the transmit and receive functions
for the rack. Table 5-2 lists these modules.
Table 5-2 Base Radio Modules
Module Description
-48 VDC powe
r supply
Converts th
e -48 VDC input to the voltages required by the other base radio modules.
Exciter Provides the transmitter and modulation functions for the base radio in conjunction with
the power a
mplifier.
Power amplifier (PA) Provides the transmitter functions for the base radio in conjunction with the exciter.
The PA acce
pts the low-level modulated RF signal from the exciter and amplifies the
signal for transmission via the RF output connector.
Base radi
o controller
Provides
signal processing and operational control for other base radio modules.
Receiver Provides the back end receive function.
Figure 5-3 shows the layout for the base radio modules.
5-6 68P81003Y71-O November 2002