Справочник Пользователя для Adtran TRC3202
Section 2, Microwave Path Engineering Basics
TRACER 2210/3202 System Manual
16
© 2002 ADTRAN, Inc.
61280012L1-1A
1.
LINE-OF-SITE
The TRACER 2210/3202 system is designed for operation in the 5725 MHz to 5850 MHz unlicensed
Industrial, Scientific, and Medical (ISM) frequency band, which is near the middle of what is traditionally
referred to as the C-band portion of X-band. Radio wave propagation in this band exhibits microwave
characteristics, which are ideally suited for point-to-point, line-of-sight communications. Line-of-sight
essentially requires that the transmitting antenna and receiving antenna are able to “see” each other, and
that the straight-line path between the two antennas is free of any obstructions, such as buildings, trees,
mountains, and, in longer paths, even the curvature of the earth.
Industrial, Scientific, and Medical (ISM) frequency band, which is near the middle of what is traditionally
referred to as the C-band portion of X-band. Radio wave propagation in this band exhibits microwave
characteristics, which are ideally suited for point-to-point, line-of-sight communications. Line-of-sight
essentially requires that the transmitting antenna and receiving antenna are able to “see” each other, and
that the straight-line path between the two antennas is free of any obstructions, such as buildings, trees,
mountains, and, in longer paths, even the curvature of the earth.
2.
DECIBELS
The received signal power equation is often expressed in a decibel (dB) format, which turns the power
multiplication and division operations into addition and subtraction operations. In general, any quantity
can be expressed in decibels. If the quantity (x) is a power level, the decibel equivalent is defined as
multiplication and division operations into addition and subtraction operations. In general, any quantity
can be expressed in decibels. If the quantity (x) is a power level, the decibel equivalent is defined as
If the quantity x is referenced to a milliwatt (mW), then the decibel-milliwatt (dBm) is used instead of a
generic decibel.
generic decibel.
Point-to-Point
Wireless communication from a single site to another
individual site. Contrast with point-to-multipoint
individual site. Contrast with point-to-multipoint
Line-of-Sight
An unobstructed, direct path exists between the
transmitting and the receiving antennas.
transmitting and the receiving antennas.
x
dB
10 log
10
x
( )
⋅
=
(dB)
x
dBm
10 log
10
x
1mW
-------------
⋅
=
(dBm)