Cisco GS7000 Installation And Configuration Manual page 109

Hub Architecture Examples
Node Return Transport
The Prisma II Baseband Digital Reverse (bdr) technology is used to transport node
returns on a single wavelength from the node to the headend. Multiple node laser
options available: Analog DWDM/CWDM, BDR DWDM/CWDM.
At the node, up to four individual 5 to 42 MHz analog reverse path signals are input
to the digital transmitter module. The transmitter processor converts each signal to
a baseband digital data stream and time-division multiplexes the multiple bit
streams into a single data stream. The data stream is then routed to the optical
transmitter module.
Each node is assigned a unique ITU wavelength that is multiplexed within the
NCBC8-BC18-NCxxxxFR passive module. The 8-node multiplexed group in turn is
inserted into its appropriate band port of the 4-band BWDM.
The output of the BWDM is optically split feeding bidirectional routes to the
headend where the two paths feed into user configurable Prisma II optical switch
(OPSW) that detects loss or drop of light. After the OPSW, the individual ITU
signals from the nodes are demultiplexed, the bdr Dual Receiver Module receives
the optical signal, performs conversion back to the baseband data stream,
demultiplexes the data stream and converts the two resultant data streams back to
analog reverse path signals for routing to termination equipment.
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