Reference Manual

Unit Description, ASU

P008374B

RXBP

MCU

Co-sited RBS

RBS 2206/2106

ASU/6

TMA/NO TMA

ANT S.n

DC-isolation

The ASU contains 6 of these boxes

CDUn RXn

CXUn RXn

Figure 99 Schematic view of a coupler

12.1.3 ASU Switch

The ASU has one common switch to set the attenuation in the 6

couplers.

12.2 Functions

The general function of the ASU is to take a small portion of the RX

signal and send that to the co-sited RBS.

The ASU also performs the following:

• Switches the attenuation in accordance with whether or not a

TMA is used. It also indicates the attenuation state via a LED.

12.2.1 RX Signal Path

The RX signal path is fed from the antennas through the feeders to the

Antenna Reference Point (ARP) of the RBS 2206. The signal is then

ﬁltered and ampliﬁed in the CDU. From the RX output of the CDU, the

signal is fed to the ASU where a small portion of the signal is fed to

the RX input of the co-sited RBS. This is shown in the ﬁgure below.

EN/LZT 720 0008 P2A

2001-11-28

173 (485)

Preliminary