Fracarro 270667, Operating Instructions Manual

Page: 14 / 32

14
English
Attention:
To conserve and protect the contact surfaces of the optical connectors, the bushing
and ferule protectors should be left in position until the connections are made or can be cleaned
using the proper tools.
Installing and removing the fi bre cable to the VOV and VOT devices:
1) Remove the protective
cover from the connector
without touching the ferule.
2) Insert the connector
following the guides until it
clicks into place.
3) To remove the fi bre,
press the connector and
pull out the cable.
4 USER INSTRUCTION
4.1 Dimensioning a Fibre Optic System
When designing a fi bre optic system it is important to consider the optical input level to the
optical receivers, suitable attenuation is required and must be calculated as the optical output
power of OPT-TX 15X0 transmitter ranges between 5.5dBm and 6.5dBm. Refer to the technical
characteristics of the receiver to check the value allowed on its optical input and then calculate the
optical attenuation allowed on the system.
ATTENTION: direct connections are not allowed between the OPT-TX 15x0 unit
and the receiver,
unless the correct line optical attenuators are used.
If the quality of the input signals is not optimised, or if a lot of signals have to be distributed to a
lot of sockets, the optical budget should be reduced or professional splitters should be used with
SC-APC connectors.
4.2 Requirements of the input signal to the OPT-TX 15x0
For the signals to be correctly transmitted through the fi bre optic, the RF signals must respect the
following requirements:
TV (DTT/CATV)
To ensure the TV signals are transmitted and received correctly, the input signals to the transmitter
should be equalised, especially if a lot of channels are being transmitted.
As an indication, the input signals should respect the following requirements:
1. The transmitter signal level should be
≥
74 dBµV to guarantee correct reception by the receivers,
even after an optical attenuation of 21dB.
2. Overall input power:
≤
-19 dBm (90 dBµV).
The overall power
≤
-19 dBm (90 dBµV) is guaranteed in the following cases:
• 40 TV channels equalised at 74 dBµV
• 20 TV channels with a maximum level of 77 dBµV
• 16 TV channels with a maximum level of 78 dBµV
• 8 TV channels with a maximum level of 81 dBµV
If the TV input signal quality is not optimal or not correctly equalised, then the system should be
designed considering an optical attenuation lower than 21dB to guarantee correct signal reception