Service Manual

GSM-205-323
Dual band TDF
31st Oct 01
Tech. 5–40
Technical Description: Horizon macro indoor
CONTROLLED INTRODUCTION
68P02902W07-B
Dual band TDF
Overview of
Dual band TDF
The purpose of the dual band twin duplexed filter (dual band TDF) Tx block is to
enable one 900 MHz antenna to serve one EGSM900 CTU for both Tx and Rx,
and an 1800 MHz antenna to serve one DCS1800 CTU for both Tx and Rx.
NOTE
The dual band TDF for the GSM850 and PCS1900 BTS
variants is not currently available.
The dual band TDF is essentially a TDF with one section providing a path for
900 MHz signals and another section providing a path for 1800 MHz signals.
There is no combining in the dual band TDF.
The dual band TDF is located in the basket above the CTUs, and attached to
the top surface of the top panel using two M6 screws.
Dual band TDF
view
Figure 5-25 shows the dual band TDF Tx block with connectors identified.
7/16 CONNECTOR TO
1800 MHz ANTENNA
(ANT. DCS1800)
SMA Tx CONNECTOR
BENEATH DUAL BAND TDF
(FROM 1800 CTU)
N-TYPE CONNECTOR TO
1800 MHz SURF CONNECTION
N-TYPE CONNECTOR TO
900 MHz SURF CONNECTION
7/16 CONNECTOR TO
900 MHz ANTENNA
(ANT. EGSM900)
SMA Tx CONNECTOR
BENEATH DUAL BAND TDF
(FROM 900 CTU)
Figure 5-25 View of dual band TDF Tx block with connectors identified