Cisco GS7000 Installation And Operation Manual page 36

Chapter 2 Theory of Operation
Forward Band Amplification 4-Way Path Description
The RF amplifier module provides all forward signal amplification outside the
optical receiver and remote PHY modules in the GS7000 Node.
The launch amplifier contains four forward amplification paths. The forward
amplification paths have one common input, and share the same input gain block,
frequency response trim circuit, thermal compensation circuit, plug-in pad, (plug-in)
linear equalizer, and interstage gain block. The interstage gain block is followed by a
2-way splitter. Each of the (two) signals from the splitter travels through an
interstage (plug-in) linear equalizer. After the interstage equalizers, the (left and
right side) signals each go through a 2-way splitter. Each of the four (forward)
signals travel through an output pad, an output gain block, a diplex filter, a
bi-directional 20 dB down forward test point, and finally an AC bypass circuit.
The thermal circuit on the RF amplifier module is designed to compensate for the RF
forward path thermal movement of the entire node RF station. This includes the
forward path amplifier module circuitry, RF cables, and optical interface board
circuitry. It does not include the thermal movement of the optical receiver or the
Remote-PHY Device.
Forward Band Linear Equalizer Module
The forward band linear equalizer modules set the overall forward path tilt of the RF
amplifier module and the 1.2 GHz SHO GS7000 Node. The 1.2GHz SHO GS7000
Node launch amplifier is shipped with two 12.0 dB and one 10.5 dB linear equalizers
installed in the RF amplifier module. One equalizer is installed in the amplifier
module common forward path and two equalizers are installed in the interstage
path of the amplifier module. Each interstage equalizer is for one side (left or right)
of the RF amplifier module. This sets the node's forward path tilt to 21 dB linear.
Forward band linear equalizer modules of other values are available. This allows the
nodes forward path tilt to be adjusted as needed. The forward band linear equalizer
module is a plug-in, field accessible module. See the equalizer charts in Appendix A -
Technical Information.
Reverse Band Amplification Path Description
The RF amplifier module provides all reverse signal amplification outside the optical
transmitter modules in the 1.2 GHz SHO GS7000 Node. It contains four reverse
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