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A30808-X3247-L14-2-7618
Technical Description (TED:BSS)
BS-240/241
Information
Base Station System
3.6 DI(=2) Amplifier Multi Coupler (DIAMCO)
For the uplink direction, the DIAMCO is used to filter and distribute the received signals
to the Carrier Units in one Rack. The DIAMCO consists of two branches constituted by:
– a receive filter
– a low noise amplifier (LNA) which takes care of a low system noise figure
– an attenuator
– a second low noise amplifier
– a power splitter which distributes the received band to the CUs (Carrier Units)
and a common part constituted by:
– a PDU (Power Distribution Unit) for two TMAs (Tower mounted Amplifier) connected
to the TMAs by means of an antenna feeder cable
– an O&M interface which transmits error messages to the BTS core via a slow O&M
bus (CAN bus)
The DIAMCO RX amplifier has two different operation modes:
– the AMCO mode where no TMA is used
– in case a TMA is used the DIAMCO is configured in the MUCO mode
3.7 Filter Combiner (FICOM)
With the FICOM, it is possible to combine up to 8 frequencies in downlink direction (TX)
in one Rack. For the uplink direction (RX), the DIAMCO has to be used to filter and
distribute the received signals to the Carrier Units. The FICOM consists of remote
tunable narrowband filters (TNF). The advantage of this filter combining technique is the
very low insertion loss, if e.g., 8 transmitters are combined to one antenna.
In principle, the FICOM offers the following functions:
• RF Functions:
– RF Power Combining
– Transmitter Spurious Signal Suppression
– Isolation between inputs
– Isolation output to input
• Control / Monitoring Functions:
– Antenna VSWR alarm thresholds setting and status reporting
– Internal Performance Monitoring
– Interfacing with BTSE
• LED Display:
– Antenna VSWR alarms
– Tuning alarms
– Presence of DC
• Lightning Protection at the RF output connector (7/16)
3.8 Tower Mounted Amplifier (TMA)
The TMA connects the antenna with the BTSE in order to amplify the receive signal and
pass through the transmit signal. The TMA contains two duplex filters, each on one RF
connector, to separate and combine the receive and transmit path inside the TMA. The
TMA consists of:
– the RX parts of the duplex filter and
– the LNA (Low Noise Amplifier) which takes care of a low system noise figure of the
RX part
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