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RTN XMC ODU
Hardware Description
Figure 1-3 Working principles of the ODU
The ODU is located between the IDU and the antenna system, implementing the functions of
frequency conversion and amplification of signals. The working principles of the ODU are as
follows:
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Issue Draft C (2014-06-20)
Processing of the signals to be transmitted
The multiplexer unit divides the input signals transmitted through the IF cable into the 350
MHz IF TX signals, O&M uplink signals, and -48 V DC power signals.
The IF TX signals are processed as follows:
1.
The IF TX signals are up-converted, filtered, and amplified to RF TX signals. Then,
the RF TX signals are sent to the AMP unit.
2.
The AMP unit amplifies the power of the RF TX signals. The power of the RF TX
signals can be controlled by the IDU software.
3.
The amplified RF TX signals are sent to the antenna through the duplexer isolation
unit.
The O&M uplink signals are the 5.5 MHz signals modulated in Amplitude Shift Keying
(ASK) mode. The signals are sent to the CTRL unit and demodulated.
The -48 V DC power signals are sent to the PWR unit. The PWR generates secondary power
supplies for each module of the ODU.
Processing of the received signals
1.
The duplexer isolation unit separates the RF input signals from other signals received
by the antenna.
2.
The RF signals are amplified through the Low Noise Amplifier (LNA) unit.
3.
The amplified RF signals are down-converted, filtered, and amplified to 140 MHz IF
RX signals and transmitted to the multiplexer unit.
4.
The multiplexer unit combines the IF RX signals and O&M downlink signals and then
transmits the combined signals to the IDU through IF cable.
The CTRL unit performs the ASK modulation on the O&M downlink signals to generate
10 MHz signals. The modulated signals are transmitted to the multiplexer unit. The CTRL
unit provides the RSSI interface and monitors the RX level through the RSSI circuit.
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Copyright © Huawei Technologies Co., Ltd.
1 Outdoor Unit (ODU)
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