Huawei RTN XMC ODU Product Description page 17

RTN XMC ODU
Product Description
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Working Principles
Figure 3-3
Figure 3-3 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 A (2013-12-20)
This subsystem implements functions such as output power control, RX gain control,
channel selection, fault alarm reporting, status setting, and status querying. The subsystem
communicates with the IDU and provides alarm information.
Power subsystem:
This subsystem contains protective circuits such as the surge protection circuits and EMC
circuits. It converts the -48V input power into multiple DC power outputs. These power
outputs are filtered and provided to each part of the ODU.
shows the working principles of the ODU.
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.
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