User's Manual

Fiber Optics Powerwave
3 - 2 Rev. P1A9-Draft 2004-11 VM100 56/EN – User’s Manual
Block Diagram
Figure 3-2. FON block diagram
Figure 3-2 shows a block diagram of the FON unit. The downlink and uplink RF signal
paths are described below.
The control unit block contains circuitry and software for control of the RF paths, local
and remote communication with O&M software, protocols for IP and R2R networks,
internal and external alarm handling, power supervision, etc.
The control unit has a number of input and output ports not shown in the block diagram.
These ports are described in the Connection Ports section on page 3-9.
RF Path 1
The RF IN port (P101) is usually connected to BTS/DL in a BMU (Base station Master
Unit), or to the UL amplifier in a FOR (Fiber Optic Repeater). The input frequency is
800 – 2200MHz and the input power 10 – 36dBm.
The first attenuator is a 16dB, 8W power device that is a security attenuator for the FON
unit. It consists of two attenuators located under the shield, see the figure. There is a
FON type without these input attenuators intended for specific configurations (described
in the Uplink RF Signal Path section in Chapter 4).
After the attenuator there is a software adjustable 0 – 20dB attenuator, manually set by
the operator via O&M software. This attenuator is correctly set when the input power to
the optical transmitter is 0dBm (examples are found in Chapter 6, Commissioning).
The optical transmitter converts the electrical RF modulated signal to a 1310 or 1550nm
optical RF modulated signal and injects it into a fiber for transmission to one or more
fiber optic receivers. The output signal power is 2 – 5dBm, or 0.5 – 2dBm at low power
(NF: 30 – 35dB and IP
3
: 30 – 35dBm).
The IP
3
is: 68dBm for channel selective repeater with 2 channels.
65dBm for channel selective repeater with 4 channels.
54dBm for band selective repeater.
16dB, 8W
FO
RF IN
TXP101
FO
RF OUT
RXP102
Control Unit
P103
TEST
–15dB
0 – 20dB
0 – 20dB
IP
16dB16dB
RF Path 1
RF Path 2
P102
Bery llium
oxide
hazard
P103
P101