Product Info

XMI (T r ansceiv er Module Internal) Module Chapter 7: XMI R eplacement Procedures
RX Main & RX Diversity Signal Handling
In the UBS Macro frame, the main RX antenna signal from each sector IDRF (Integrated
Duplexer RX Filter) is applied to the corresponding sector main RX RF input of XMI 1. This
input is applied to the main receiver path of the corresponding XMI 1 sector receiver .
F or low capacity frames with one XMI, the diversity RX antenna signal from each sector IDRF is
applied to the corresponding sector diversity RX RF input of XMI 1. This input is applied to the
diversity receiver path of the corresponding XMI 1 sector receiver .
F or mid capacity frames with two XMIs, the main RX antenna signal from each sector IDRF is
applied to the corresponding sector main RX RF input of XMI 1. XMI 1 provides pre -amplified
main RX antenna signals at its RX EXP OUT connector . This connector connects to one of the
following:
• optional RX splitter XMI 1 RX EXP IN connector . The RX splitter splits the main RX
antenna signal and distributes it to the RX splitter XMI 2 RX EXP OUT connector . This
connector is cabled to XMI 2 RX EXP IN connector . This connection provides the main
receiver path of the corresponding XMI 2 sector receiver .
• optional XMI 1/XMI 2 RX cross -connect cable. This cable connects XMI 1 RX EXP OUT
connector to XMI 2 RX EXP IN connector . This connection provides the main receiver path
of the corresponding XMI 2 sector receiver .
F or mid capacity frames with two XMIs, the diversity RX antenna signal from each sector
IDRF is applied to the corresponding sector diversity RX RF input of XMI 2. XMI 2 provides
pre -amplified diversity RX antenna signals at its RX EXP OUT connector . This connector
connects to one of the following:
• optional RX splitter XMI 2 RX EXP IN connector . The RX splitter splits the diversity RX
antenna signal and distributes it to the RX splitter XMI 1 RX EXP OUT connector . This
connector is cabled to XMI 1 RX EXP IN connector . This connection provides the diversity
receiver path of the corresponding XMI 1 sector receiver .
• optional XMI 1/XMI 2 RX cross -connect cable. This cable connects XMI 2 RX EXP OUT
connector to XMI 1 RX EXP IN connector . This connection provides the diversity receiver
path of the corresponding XMI 1 sector receiver .
The XMI automatically detects whether the RX signals are coming directly from the IDRFs
through the QMA cables or indirectly through the RX Expansion ports and adjusts its internal
RX gain accordingly . This automatic detection and gain adjustment occurs only during an
XMI power -up or reset.
XMI RX Output Signal Handling
Each XMI sector main/diversity receiver detects the RF RX carriers for the corresponding
sector . The detected main/diversity RX signals are A/D converted. These converted digital
signals are applied to the RX baseband control array . This array selects the best main/diversity
RX signals for the carriers assigned to the XMI.
The RX baseband control array outputs the selected RX digital signals to the RX
baseband bus. The RX baseband bus is applied to the Serializer/De -serializer & Data
Multiplexer/De -multiplexer . This stage multiplexes the RX baseband bus signals and converts
them to a high -speed serial data signal. This multiplexed RX baseband serial data signal is
applied to the high -speed serial data interface which provides 1.2288 Gbps links to the HSL
data ports on the front panel of the XMI.
7 -4 68P09283A64 -3
FOA SEP 2007