NEC PASOLINK+, Руководство пользователя

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MTD-PL-028/141005 PASOLINK
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155 MB 1+0/1+1 SYSTEM
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1. INTRODUCTION
NEC’s new PASOLINK
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series; 6-38 GHz 155 Mbps Synchronous Digital Hierarchy (SDH)
microwave radio systems are designed to transmit one synchronous transport module (STM-
1, 155 Mbps). They operate at the 6-38 GHz radio frequency band using quadrature amplitude
modulation (32-QAM or 128-QAM), and have a transmission capacity of OC3 or STM-1. In
addition to the PASOLINK
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systems for short distance links, NEC offers a complete product
line of STM-1 radio systems that includes the 4, L6, 7, 8, 13 GHz 155 Mbps 128 QAM and 4,
5, U6, 8, 11 GHz 155 Mbps 64 QAM systems for long distance use. For those systems,
please refer to the other technical descriptions.
The PASOLINK
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radio systems are fully compatible with SDH Network Elements (NE). The
systems consist of antennas, outdoor units (ODU), and indoor units (IDU). They are
connected through a coaxial cable for each radio channel. Available configurations are non-
protection type (1 + 0) and protection type (1 + 1). The protection type is available for twin-
path type and hot-standby type.
Regarding antenna configurations there are two types available. There is a one-antenna
system employing hybrid (HYB) RF combiner and divider, and a two-antenna system method
using each antenna for two ODUs independently. The hybrid is the passive device that
combines and divides the signals between two ODUs and an antenna. Therefore, the one-
antenna system requires only a single antenna, however, additional loss between ODUs and
antenna have to be considered. On the other hand, the two-antenna system has high system
gain as same as non-protection type.
STM-1 interface can be selected for electrical or optical. Therefore, PASOLINK
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systems are
useful in fiber optical transport system (FOTS). Additionally, Fast Ethernet interface can be
selected for IP network.
The PASOLINK
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employs a full digital MODEM using enhanced signal processing techniques
and forward error correction (FEC). Moreover, the bit-error-rate characteristics against
receiver input signals are excellent for applying FEC (32-QAM System: MLCM (multi-level
code modulation) and RS (Reed Solomon method), 128-QAM System : QAM and RS).
The equipment can be installed easily and quickly using a PC (as Local Craft Terminal), and
as a maintenance tool.