NEC PASOLINK+, Manual

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MTD-PL-028/141005 PASOLINK
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155 MB 1+0/1+1 SYSTEM
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5. DESIGN CONSIDERATIONS
5.1 Protection Capability
PASOLINK
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provides a protection switching system of Hot-standby protection (1 + 1), and
twin-path protection (1 + 1).
1. Non-Protection System
Non-protection system consists of one ODU, one IDU for 1 + 0 System, and one antenna.
2. Hot-Standby System
Hot-Standby system consists of two ODUs, one IDU for 1 + 1 system, and one or two sets of
antennas. The protection switch of this systems is performed by the TX switches on the
ODUs at the transmitting end and Hitless switch on the 150 M INTFC (or OPT INTFC) module
in the IDU at the receiving end.
3. Twin-path System
Twin-Path system consists of two ODUs, one IDU for 1 + 1 System, and two sets of
antennas. The protection switch of this system is performed by the Hitless switch on the 150
M INTFC (or OPT INTFC) module in the IDU at the receiving end.
5.2 Antenna
The complete menu of PASOLINK
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antennas includes diameters of 0.3m to 1.8m. They are
designed to meet stringent requirements on mechanical rigidity. Antennas with diameters of
0.3m to 1.8m can be mounted directly to the ODU, making waveguides obsolete. This has
relevant cost and reliability merits and makes the installation quicker and easier. The
PASOLINK
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pole mounting structure is designed in a way that the ODU can be replaced while
keeping the antenna and mounting bracket, including orientation, in place. The reflectors of the
antennas are covered with white diffusive paint and the mounting structure is hot-dip
galvanized.
In the 6 - 8 GHz band, coaxial or waveguide cable with transducer is used for connecting
between the ODU and IDU.
5.3 Transmitter-Receiver (ODU)
A block diagram is shown in Figure 4-5.
The transmitter-receiver is designed to handle a STM-1 signal in 6-38 GHz bands. The
equipment is designed to withstand severe weather conditions.
32/128-Quadrature amplitude modulation (32/128 QAM) is applied.
Local Oscillator is employed for APC (Automatic Phase Control) loop circuit at the transmitter
and receiver.