Page 196 - CITS - Electronic Mechanic - TT - 2024

ELECTRONICS MECHANIC - CITS

There are two types of optical fibers, glass, and plastic. Plastic fiber is used for short communication. Optical fiber
transfers data at the speed of light in the glass.
Optical fiber cable uses light pulses instead of electrical pulses to transmit data. The potential hazard of Infrared
red light used in telecommunications cannot be seen by the naked eye.
Optical fiber cable comes in single-mode or multimode connections.
Single Mode

The single-mode allows only one mode of light to transmit at a time through the core, which makes for higher
bandwidth.
Single-mode fiber optic, the number of light reflections in the core is less resulting in low attenuation and allowing
data to travel further, faster. Single-mode provides the lowest losses in communication.
Multi-Mode
Multimode connections have a larger core diameter. It allows multiple wavelengths of light transmitted in multiple
paths at once.
Multimode connections are used over shorter distances as signal attenuation will be more, the data transfer rate
is slow as a number of reflections in the core are more.
Advantages

Extremely high bandwidth and speed.
Impervious to electromagnetic interference.
Several kilometers of optical fiber cable can be made cheaper than the equivalent length of copper cable.
Optical fibers usually have a longer life cycle for more than 100 years.

The loss of signal in fiber optic cable is very less than that in copper wire.
The smaller size and lightweight than a comparable copper wire cable.
Less weight can be bundled together.
Optical fiber is thinner and can be drawn to smaller diameters than copper wire.
Disadvantages

More unsafe than damage compared to copper wires.
Should not twist or bend fiber optic cables too tightly. Follow specification for cable bend radius.
Applications
Used in Telephone signals, internet communication, cable television.
Multi Dwelling Unit (MDU)

The Multi Dwelling Unit is a customized solution for connecting multiple TVs within the same multi storied building
with a single or two Dish Antennae to receive Direct-to-Home service. Common dish is installed on the terrace of
the multi storied building which gives signal to DTH STBs connected to TV sets in multi storied building. Once the
dish is installed, residents have the choice to subscribe for the DTH services.
Direct-to-Home entertainment is based on the concept of receiving the services directly on your television from a
satellite through DTH box. A small dish is installed in your home to receive the signals from the satellite. However,
one connection needs one dish to receive the satellite signals. This leads to many dishes in any multi storied
building having many subscribers.
MDU is the solution that reduces the number of dishes to one or two in a multi storied building for all the subscribers
in the building.

Advantage of MDU
Each and every customer in the building does not have to have a separate Dish Antenna to receive DTH services.
Additional dish is not required to be installed for any additional subscriber in the building.
It is easy to maintain one or two dish antenna in a building.

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CITS : E & H - Electronics Mechanic - Lesson 108 - 117