Cisco Model GS7000 4-Port Node 1 GHz with 42 54 Split Installation Guide
Reverse Path
OL-29643-02
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Reverse Path
Introduction
Reverse path refers to signals received by the node from the cable distribution
network. These signals are amplified in the node and returned to the headend
optically through the fiber portion of the network. The reverse path is not used in all
networks.
network. These signals are amplified in the node and returned to the headend
optically through the fiber portion of the network. The reverse path is not used in all
networks.
Reverse Path Signal Routing
GS7000 Node reverse path signal routing functions are described below.
Stage Description
1
Reverse path RF signals are applied to node output ports 1, 2, 4, and 5. A
fifth reverse path RF signal can be applied to node auxiliary output port
3 or 6 if the node is configured for local reverse path injection.
fifth reverse path RF signal can be applied to node auxiliary output port
3 or 6 if the node is configured for local reverse path injection.
2
The RF signals from each of the four node output ports are amplified
independently in the RF amplifier module and routed to the Reverse
Configuration Module (RCM).
independently in the RF amplifier module and routed to the Reverse
Configuration Module (RCM).
3
Each of the reverse amplification paths in the RF amplifier module also
contains padding, trimming, filtering, -6 db wink, and RF On/Off switch
circuitry.
contains padding, trimming, filtering, -6 db wink, and RF On/Off switch
circuitry.
4
The RCM determines how RF signals from the different node output
ports are combined and routed to the four transmitter module paths on
the Optical Interface Board (OIB). The 4X1 RCM combines the reverse
path signals from the four node output ports together and directs them
to the transmitter module 1 path on the OIB. (Note that other RCMs
combine and direct signals to OIB transmitter module paths 2, 3, and 4
differently.)
ports are combined and routed to the four transmitter module paths on
the Optical Interface Board (OIB). The 4X1 RCM combines the reverse
path signals from the four node output ports together and directs them
to the transmitter module 1 path on the OIB. (Note that other RCMs
combine and direct signals to OIB transmitter module paths 2, 3, and 4
differently.)
5
The RF signals travel across the OIB to transmitter module 1 (and/or
modules 2, 3, and 4, if used and proper RCM is installed.) The
transmitter modulates the RF signals entering it onto an optical carrier
and routs it through the fiber portion of the network back to the
headend.
modules 2, 3, and 4, if used and proper RCM is installed.) The
transmitter modulates the RF signals entering it onto an optical carrier
and routs it through the fiber portion of the network back to the
headend.
Note: Node output ports 3 and 6 can be configured as primary reverse ports. See
Reconfiguring Reverse Signal Routing (on page 124) for further details on this
configuration.
Reconfiguring Reverse Signal Routing (on page 124) for further details on this
configuration.