Руководство По Установке для Cisco Prisma II bdr Dig Rev 2 1 Dual Mux Sys for High Density Installations
Reverse Balancing the Node with the Enhanced Digital Reverse Modules 78-741939-01 Rev C
3-2
Preparing for Reverse Balancing
Note for Reverse Path
When balancing the reverse path, reference your system design print for the
required reverse signal level. Use appropriate padding and equalization to provide
proper signal level to the reverse transmitter.
Baseband Digital Reverse Balancing
Baseband digital reverse technology is designed to carry reverse path signals from 5
MHz to 42 MHz. This technology digitizes the analog input and then sends a high-
speed serial bitstream over fiber to a digital receiver at the link end. By converting
the analog RF band to a digital format, two full bandwidth digital links can be
multiplexed together over the same fiber and recovered at the receiver.
There are a variety of test equipment combinations that enable proper balancing of
There are a variety of test equipment combinations that enable proper balancing of
the reverse path. Regardless of the type of equipment used, the balancing process is
fundamentally the same.
A reverse RF test signal (or signals) of known amplitude is injected into the RF path
A reverse RF test signal (or signals) of known amplitude is injected into the RF path
at the RF input of the node. The reverse transmitter converts the RF test signal(s) to
an optical signal and transmits it to the headend (or hub site) via fiber optic cable. At
the headend, the reverse optical receiver converts the optical signal back to an RF
signal which is then routed out through the receiver’s RF output. The amplitude of
the injected test signal must be monitored at the receiver’s output, and compared to
the expected (design value) amplitude.