Andrew MR903D Panduan Pengguna - Halaman 2
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Halaman Cetak4. Functional Description
The operation principle of the miniRepeaters is given
with regard to the following block diagram.
Downlink signals from the BTS reach the internal
duplexer through the "to/from BTS" RF port. Following
the DL path from the duplexer, the RF signals are
amplified by an LNA, which feeds the amplified
signals to a mixer. The mixer converts the signals
down to an intermediate frequency (IF), where a high
rejection IF filter provides excellent selectivity to allow
only the user's frequency band to be repeated. After
the IF filter, the signals are re-converted to the original
frequency by means of another mixer. A final amplifier
boosts the RF signals to the required output power.
After the final amplifier, a power detection circuit
measures the output power and controls the gain
through a closed loop feedback circuit. This feature is
the automatic level control (ALC), which prevents the
repeater
from being overdriven and maintains
intermodulation products and spectrum emissions
below the regulation limits. Finally, the RF signals are
fed to the external antenna through the duplexer and
"to/from Mobile" RF port.
The uplink signals are received by the external
antenna through the "to/from Mobile" RF port and are
then fed to the duplexer. After the duplexer the RF
circuitry and functionality is identical to the downlink
path, which provides high rejection filtering for the
desired
operation
frequency
functionality.
5. Cabinet Drawing
Andrew Wireless Systems GmbH * Industriering 10 * 86675 Buchdorf * Germany *
Page 2
Attenuation
manual
setting
automatic
band
and
Phone: +49 9099 69-0 * Fax: +49 9099 69-930 *
email: [email protected] * http://www.andrew.com
MR803D, MR853D, MR903D and MR1903D
6. Wall Mounting
E0783B0
miniRepeater
The miniRepeater may only be mounted
horizontally to a wall according to the above
drawing to ensure the natural convection
cooling. Do not mount the miniRepeater to the
ceiling!
Always choose a mounting location that
avoids condensation!
7. Mechanical Specification
Size H x W x D
Weight
Sealing Class
8. Environmental and Safety Specifications
The environmental specifications are according
to ETS 300 019 (European Telecommunication
Standard) and the safety specifications are
according to UL Std No 1950 and CAN/CSA-
C22.2 No. 60950. For further details please ask
your supplier.
ALC
9. 20 dB Bandwidth
MR803D, 18 MHz Filter
MR853D, 1.5 MHz Filter
MR853D, 10 MHz Filter
MR853D, 12.5 MHz Filter
MR853D, 25 MHz Filter
MR903D, 6 MHz Filter
MR1903D, 5 MHz Filter
MR1903D, 10 MHz Filter
MR1903D, 15 MHz Filter
G0825Z8
User's Guide for
Mounting
bracket
Wall
V1550_X03
114 x 154 x 51.5 mm
(4.5 x 6.1 x 2.0 inch)
0.7 kg
IP30
18.7 MHz
2.1 MHz
10.7 MHz
13.2 MHz
24.7 MHz
6.6 MHz
7.0 MHz
11.0 MHz
16.0 MHz
20 dB bandwidth