Alcatel-Lucent 9500 MXC User Manual page 866

Protected and Diversity Operation
Vol. VI-F-10
A DC-DC converter provides the required low-voltage DC rails from the -48 Vdc
supply.
In the receive direction, the signal from the diplexer is passed via the LNA (Low
Noise Amplifier) to the Rx mixer, where it is mixed with the receive local
oscillator (RXLO) input to provide an IF of between 1700 and 2300 MHz. It is
then amplified in a gain-controlled stage to compensate for fluctuations in
receive level, and in the IF mixer, is converted to a 126 MHz IF for transport via
the ODU cable to the RAC.
The offset of the transmit frequencies at each end of the link is determined by the
required Tx/Rx split. The split options provided are based on ETSI and FCC
plans for each frequency band. The actual frequency range per band and the
allowable Tx/Rx splits are range-limited within 9500 MXC to prevent incorrect
user selection.
A power monitor circuit is included in the common port of the diplexer assembly
to provide measurement of transmit power. It is used to confirm transmit output
power for performance monitoring purposes, and to provide a closed-loop for
power level management over the specified ODU temperature and frequency
range.
The INU/INUe supports protection via hot-standby, space diversity, frequency
diversity, or ring.
All options are supported by RAC 30, RAC 3X or RAC 40.
Figure F-4 on page F-11 shows a basic protected or diversity INU using two
RAC 30 plug-ins. It also incorporates two DAC 16x plug-ins and an NPC. The
NPC provides backup (protection) for the timing processor and DC-DC power
supply functions within the NCC.
For a protected or frequency diversity configuration the two ODUs would
normally connect to a common antenna using a coupler, which can be specified
for unequal or equal splits. For space diversity or ring protection, each ODU is
attached to its own antenna.
Protected NCC operation is identical to non-protected.
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