Service Manual

GSM-204-323
DDF
31st Oct 01
Tech. 5–44
Technical Description: Horizon macro outdoor
CONTROLLED INTRODUCTION
68P02902W02-A
DDF
Overview of
DDF
The dual-stage duplexed combining filter (DDF) differs from the DCF in having a
second stage of combining to allow a third CTU Tx input. This third CTU Tx
input is connected to either:
 A feedthrough plate connector for a single additional CTU or
 An HCU plate connector for combining two additional CTUs.
The DDF is located in the basket above the CTUs and is attached to the top
surface of the top panel using two M6 screws.
DDF view
Figure 5-29 shows a view of the DDF Tx block with connectors identified.
HOLE FOR TOP
PANEL BASKET
ATTACHMENT
N-TYPE CONNECTOR TO
SURF
TWO SMA Tx CONNECTORS
BENEATH DDF (FROM CTU)
7/16 CONNECTOR
TO ANTENNA
N-TYPE CONNECTOR
FROM CTU BY
FEEDTHROUGH PLATE
OR HCU
HOLE FOR TOP
PANEL BASKET
ATTACHMENT
COOLING FINS
Figure 5-29 DDF Tx block view with connectors identified