Forward Path - Cisco GS7000 Installation And Operation Manual

Chapter 2 Theory of Operation

Forward Path

Introduction
Forward path refers to signals received by the node from the hub or headend. These
signals are amplified in the node and routed to subscribers through the cable
distribution network.
Forward Path Signal Routing
1.2 GHz SHO GS7000 Node forward path signal routing functions are described
below.
Stage
1
2
3
4
5
14
Description
1310 nm or 1550 nm optical signals from the hub or headend are applied to the
receiver module in the 1.2 GHz SHO GS7000 Node.
The receiver module detects the signal on the optical carrier applied to it and
outputs an electrical RF signal to the node Optical Interface Board (OIB).
The RF signal travel across the OIB and cables to the Launch Amp which splits
the RF signals entering it equally between the four forward amplification paths
in the RF amplifier module.
The forward amplification paths in the RF amplifier module is composed of one
common input amplification stage and one common interstage amplification
stage in series followed by a 4-way power divider. Each output of the power
divider feeds a power doubler output amplification stage. This topology
provides four node output ports with one common input signal source.
The common forward amplification path in the RF amplifier module also
contains padding, trimming, thermal compensation, equalization, and filtering
circuitry.