Reference Manual

Table Of Contents
Description 10 (37)
© Ericsson. Commercial in confidence Rev F 2001-07-17 LRN/X-99:083
Combining and Distribution Unit (CDU)
The CDU combines the transmitted signals from the transceivers and distributes the
received signals. Duplex filters are included in the CDU. A measuring coupler, providing
forward and reflected power measurements for Voltage Standing Wave Ratio (VSWR)
calculations is located in the CDU.
Two different CDU types exist for GSM 900 and 1800 (CDU-F and CDU-G) and one CDU
type for GSM 800 and GSM 1900 (CDU-G).
With hybrid combining, CDU-G. Allows base band or synthesised frequency hopping.
With filter combining to support large configurations, CDU-F. Allows base band
frequency hopping. CDU-F is optimised for giving large configurations maximum
output power on minimum number of antennas.
Figure 6. CDU-G and CDU-F.
The duplex filters allows both receiver and transmitter path connections to a common
antenna. The duplex configurations also minimise the number of required feeders and
antennas as well as the combining loss in the transmission path.
The different CDU types are further described in the Radio Specifications for the different
frequencies.
The CDU-G and CDU-F are hardware prepared to support EDGE.