Справочник Пользователя для Andrew Wireless Innovations Group RPT-MR303V-90
User’s Manual for Repeater
MR303D Varia
M0041A8B.doc
Id.-No. 153114
Page 9
26-Oct-2000
1.2 Functional Description
The MR303D Varia is a repeater operating in the GSM900 frequency range. The
operation principle for uplink and downlink is depicted in the following block
diagram:
operation principle for uplink and downlink is depicted in the following block
diagram:
figure 1-1 Block diagram
1.3 Downlink
Downlink signals are received by the external antenna and fed to the duplexer. The
duplexer is the frequency separation unit that splits and recombines uplink (UL) and
downlink (DL).
duplexer is the frequency separation unit that splits and recombines uplink (UL) and
downlink (DL).
After processing through the duplexer the signals are transferred to a pre-amplifier
and then enter the attenuation selection. The gain of the repeater can be set by
introducing attenuation into the amplifier chain (see chapter 3.2 Setting the
Attenuation). Then the signals are relayed to a mixer. The mixer converts the signals
down to an intermediate frequency (IF). An IF filter provides the selectivity of the
repeater. After the IF filter the signals are reconverted to the original frequency again
with another mixer. A final amplifier amplifies the signal once again to the required
output power.
and then enter the attenuation selection. The gain of the repeater can be set by
introducing attenuation into the amplifier chain (see chapter 3.2 Setting the
Attenuation). Then the signals are relayed to a mixer. The mixer converts the signals
down to an intermediate frequency (IF). An IF filter provides the selectivity of the
repeater. After the IF filter the signals are reconverted to the original frequency again
with another mixer. A final amplifier amplifies the signal once again to the required
output power.
After amplification a power detection feature, called automatic level control (ALC),
measures the output power and controls the gain. The ALC keeps intermodulations
below - 36 dBm. Finally, the signals are supplied to the antenna output.
measures the output power and controls the gain. The ALC keeps intermodulations
below - 36 dBm. Finally, the signals are supplied to the antenna output.