Alcatel-Lucent 9500 MXC User Manual page 862

RAC 40 Transmit
RAC 40 Receive
Vol. VI-F-6
RAC 40 Block Diagram
Figure F-2.
Back Plane
ODU Telemetry
-48 Vdc to ODU
Bus
DMX
Bus
MUX
RAC 40
Clock uP TDM
Bus Bus Bus
The Bus Demux extracts the payload and overhead traffic from the TDM bus and
passes it to FiFo (First-in, First out) buffer and Mux stages which accepts,
synchronizes and frames:
• Up to 64xE1, 84xDS1, or STM1/OC3 channel capacities.
• One NMS channel plus INU-to-INU communication overhead.
• Up to six auxiliary data channels.
The framed data stream is passed to the modulator, where:
• FEC encoding is applied: Reed-Solomon with block interleaving, and Viterbi.
• It is rate modulated for the selected (in CT) capacity and bandwidth/modulation
options.
• 90 degree phase-shifted I and Q data streams are generated.
The I and Q streams are converted to analog signals in the D/A converter, and
passed to the quadrature modulator, which impresses the data onto a 311 MHz IF
carrier. This IF is passed to the N-Plexer, where it is combined with telemetry
and reference oscillator signals, plus 48Vdc power, to go to the ODU.
Receive traffic is carried on a 126 MHz IF from the ODU. At the N-Plexer it is
extracted along with telemetry data, which goes directly to the NCC.
The 126 MHz signal is passed to a gain controlled amplifier, which compensates
for losses in the ODU cable. Two data streams are taken from the amplifier:
• One is directed to the demodulator via an A/D converter.
Tx
I
MUX
FIFO
MOD
Q
uC
Rx
DMX DMD
FIFO
Rx/Tx Diversity Bus
RefOsc
311MHz N-
QUAD
D/A
PLXR
MOD
ODU 300
~
311 MHz
A/D AGC
126MHz
A/D
XPIC XPIC
IN OUT
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