Forward Rf Path - Motorola Starline SG1000 Installation And Operation Manual

2-8 Overview

Forward RF Path

The receiver module is integrated within the E-pack. The receiver's integrated optical hybrid
photo-detector improves RF performance over the entire 47 through 870 MHz passband. An
optical-power monitor circuit provides assessment of the fiber link status. The receiver module
is fully compatible with the status-monitor transponder enabling remote monitoring of key
module and link performance parameters.
A positive intrinsic-negative (PIN) attenuator, driven by an integrated thermal control circuit,
provides temperature compensation for the forward RF path.
An SG1000 distribution response correction (1DR) plug-in board follows the PIN attenuator and
is selected during configuration according to the 750 or 870 MHz requirements. It provides a
portion of the required slope characteristic. Plug-in forward equalizers located before each
output hybrid provide the remainder of the slope characteristic.
Each output stage uses a Silicon or GaAs power-doubled output hybrid. The diplex filters are
selected during configuration according to the preferred frequency split. You can change the
filters to accommodate different splits. You will also need to change the RPLPF in the return
transmitter.
The SG1000 can be factory configured for one or two outputs. If you require only one output, the
second RF output is not populated on the E-pack. To field upgrade a single-output node to a
dual-output node, contact your Motorola sales representative for the appropriate kit.
Port 1 is a dedicated node output in the SG1000. Where you install the furnished MB-JMP
jumper determines whether the other path feeds Port 2 or Port 3. The model MB-SP splitter and
model MB-DC/* directional coupler are available separately and provide an output at Port 2 and
Port 3. The MB-SP provides equal output levels, while the MB-DC/* provides one high-level port
and one low-level port. The high-level signal is routed to Port 2 or Port 3 and is based on the
MB-DC/*s orientation during installation. Figure 2-1 illustrates the port numbers identified on
the amplifier cover.
For each port, the status monitor transponder input is taken from the port one, forward RF
output, test point. A directional coupler is used to ensure that the operation of the RF output
test point is unaffected by the presence or absence of the status monitor. A new MCX connector
has been added before the return-path transmitter that enables the status monitor to inject its
output signal.
SG1000 Split Third Port Installation and Operation Manual