Operation Manual

Fiber Distributed Antenna System (Fiber DAS)
17
Figure 14
DETECTOR
LASER
DRIVER
ETHERNET
MODEM
OPTO OUT
DETECTOR
MONITOR
TX-LVL
DL IN 1
DL IN 2
TP DL
STEP ATT
Attenuator 1
Downlink 1
Attenuator 1
Downlink 2
Attenuator 2
Downlink 1
Attenuator 2
Downlink 2
STEP ATT
STEP ATT
STEP ATT
FOI Downlink Block Diagram
The RF drive levels are measured and accessible in the web interface.
TP DL is a t
est point measurement port for the do
wnlink path. The RF level at TP DL will be the same as the input to
the DL ports minus the GUI attenuator settings.
TP DL = “DL IN 1" minus “Att. 1 Downlink 1" minus “Att. 2 Downlink 1".
TP DL = “DL IN 2" minus “Att. 1 Downlink 2" minus “Att. 2 Downlink 2".
Example: Input into DL is -25dBm with the GUI setting for “Att. 1 Downlink 1" of 10 and a GUI setting for “Att 2
Downlink 1" of 0. The test point measurement will be: -25dB (input) minus 10dB (attenuator #1) minus 0dB
(attenuator #2) = -35dBm.
Figure 15 is a block diagram showing the uplink path in the FOI and how the test port is connected. There are two
common attenuators, and two uplink attenuators that can be set in the uplink path.
Figure 15 FOI Uplink Block Diagram
DETECTOR
DETECTOR
CURRENT
SENSOR
ETHERNET
MODEM
OPTO IN
RX-LVL
UL OUT 2
UL OUT 1
TP UL
Attenuator
Common 1
PHOTO
DETECTOR
Attenuator
Common 2
Attenuator
Uplink 1
Attenuator
Uplink 2
STEP ATT STEP ATT
STEP ATT
STEP ATT
RX POWER 1
RX POWER 2
The UL test port on the FOI is tapped before the individual uplink path attenuators. The output level of TP UL will be:
TP/UL[dB] = “Att. Uplink 1" setting - 20dB
TP/UL[dB] = “Att. Uplink 2" setting - 20dB
Example: If the FOI GUI setting for “Att. Uplink 1" is 0, the test port uplink path 1 signals will be 20dB lower than the
uplink signal on the “UL Out 1" port.
Example: If the FOI GUI setting for “Att. Uplink 2" is 20, the test port uplink path 2 signals will be equal to the uplink
signals on “UL Out 2" port.