User Manual

CDU-D Combining and Distribution Unit
4.1 TX Part
The TX part handles the transmission of signals from the TRUs to the antenna.
The TX part consists of the following:
• Three combiner units (CU)
• A filter unit (FU or FUd)
CU
CDU-D contains three CUs. The CU combines two TX signals to a common
output. Each CU consists of the following:
•Circulators
• Tuneable Band Pass filters
Circulator
The circulator provides a uni-directional transmission
path and protects the transmitter inputs from reflected
signals.
Tuneable Band
Pass filters
The tuneable band pass filters allows through TX
signals for one radio channel, and removes unwanted
out-of-band signals
FU/FUd
The FU removes unwanted signals and supervises the antenna. There are
two types of FUs:
• FUd (with duplexer) (GSM 900 and GSM 1800 versions)
• FU (without duplexer) (GSM 1800 version) TMA configurations
The FUd consists of the following:
• A duplex filter (duplexer) (GSM 900 and GSM 1800 versions only)
• A Measurement Coupler Unit (MCU)
The FU (GSM 1800 versions only) consists of:
• TX Band Pass filters (TXBP)
• A Measurement Coupler Unit (MCU)
Duplexer (FUd)
The duplexer allows simultaneous transmission and
reception on the same antenna. It lets the TX signals
pass to the antenna and distributes the RX signals
to the RXDA.
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EN/LZT 720 0279 Uen R1A