Alcatel-Lucent 9500 MXC User Manual page 861

RAC 30 Receive
RAC 40
3DB 23063 ADAA - Rev 004 July 2007
Receive traffic is carried on a 126 MHz IF from the ODU. It is extracted at the
N-Plexer, along with telemetry data, which goes directly to the NCC.
The 126 MHz IF is passed to an analog to digital converter via a gain controlled
amplifier, which compensates for losses in the ODU cable. The digital stream
from the converter is fed to the Vantex demodulator, where:
• It is demodulated to derive the framed baseband data.
• FEC decoding is applied.
• Adaptive equalization is applied.
• Errorless receive switching is initiated for protected and diversity link
configurations.
• Receive signal quality-monitoring data is extracted for threshold alarms and
G.826 statistics.
The output is passed to the de-multiplexer where framing data is removed to
recover traffic and overhead data streams. A FiFo buffers and de-jitterizes the
data prior to the Bus Mux, which inserts it onto the TDM bus.
RAC 40 operates with ODU 300; refer to Figure F-2 on page F-6.
RAC 40 is similar in operation to RAC 30, except for:
• The incorporation of a micro-controller to manage the modulator and
demodulator functions.
• XPIC In/Out connections.
• Reed-Solomon and Viterbi FEC.
9500 MXC User Manual
Vol. VI-F-5