Fiber-Span LLC FS31X-8 用户手册

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Fiber Optic RF Repeater System 

 
Fiber-Span provides product to enable RF signal to be distributed via optical fiber 
cable.  RF signal sources can be used from over the air (OTA) from a Radio Base 
Station (BS), OTA from handheld devices, or directly from a BS radio.  RF signals 
are converted to modulated light for transport through optical fiber media to remote 
locations.  Modulated light is converted back to the original RF signal where it is 
processed through filtering and amplification to allow the RF signal to be re-radiated 
in the remote location.   In a bi-directional RF system, the process is the same 
resulting in remote RF signals that are sent back simultaneously. 
 
Fiber-Span product functionality 
 
OTA system -  RF signals from a remote base station are interchanged usually from 
a roof top antenna that is connected to an Integrated Head-end Unit (IHU).  The IHU 
receives downlink signals from the base station and sends uplink signals back to the 
base station.  The IHU distributes signals via fiber optics to remote location and also 
is capable of simultaneously interfacing with a Distributed Antenna System (DAS) 
for short range RF distribution.   
 
 
 

 

 
 
 
 

Figure 2.  Typical OTA Optical RF distribution System 

 
 
Local Base Station System – Signals from a local base station interface to optical 
distribution equipment through Base Station Units (BSU), or directly to a Fiber 
Transceiver Unit (FTU).  The BSU sometimes interfaces the Base Station to the 
FTU. The BSU is used to passively condition RF levels or serve as RF filters when 
applicable.   The FTU performs bi-directional optical-RF conversions.  Optical 
signals are sent to the Remote Repeater Unit (RRU).  The RRU is designed for use 
as a remote end of a bi-directional RF distribution system.  The RRU RF port works 
with a direct connected RF antenna or to a Distributed Antenna System (DAS).   
The RRU is connected via optical fibers to a Fiber Transceiver Unit (FTU) to 
complete a point to point RF link.    

 
 
 
 

Remote Base 
Station 

DAS in 
Building 

DAS in 
Building 

Optical 

Fiber