Post on 11-May-2015
description
Presentation By:Tarun Kumar MatriayaEC-B VII SEMRoll No: 0700131202
Industrial Training Seminar
Outline
Summer Training at North Central Railways, Allahabad from 30th June, 2009 to 30th July, 2009.An amazing experience as I got to see, How exactly the communication system works for Indian Railways.Main Objective was to learn Optical Fibre Communication In Railways.
Contents
Introduction to Indian RailwaysIntroduction to Optical Fibres.Advantages of Optical Fibres.Disadvantages of Optical Fibres.Application of Optical Fibres.Types Of Optical Fibres.Optical Fibre CommunicationWorking of OFC.Use Of OFC in Railways.
Introduction to Indian Railways
1832: The first proposal was introduced for having Railways In India.1853: On April 16th, at 3:35 pm, The first train left from Bombay to Thane.
November 1947 : John Mathai (not formerly designated as Minister to Railways) presents the first Railways budget for Independent India.
Present Railway Minister: Dinesh Trivedi.
Optical Fibre
An optical fibre ( or fiber ) is a glass or plastic fibre that carries light along it’s length.
It has two main component layers: A Core & A Cladding.
Light is kept in th “core” of optical fibre.
Cladding is for the protection of fibre.
Advantages of Optical fibre.
Thinner than other tubes.Less expensiveHigh Carrying Capacity.Provides a very large BandwidthLess signal distortionNon- flammableLight Weight
Fibre Optic Disadvantages.Expensive over short distance.Very high Installation charges
& demands high skills.Adding additional nodes is
difficult.
Areas Of Application
TelecommunicationLocal Area NetworksCable TVCCTVOptical Fibre Sensors
Optical Fibre Construction
Core: Thin Glass Center of the fibre where light travels.
Cladding: Outer OpticalMaterial surrounding theCore.
Buffer Coating: PlasticCoating that protects theFibre.
Material Used.
The “Core” , & the lower refractive index “Cladding” , are typically made of high quality silica glass, though they can be both made of plastic as well.
Fiber Optic Layers.
Consists of three concentric sections.
plastic jacket glass or plasticcladding fiber core
Mode Of Propagation
Two main categories that are used in Fibre
Optic Communications are:
Multi-mode Optical Fibre
Single Mode Optical Fibre
Fibre Optic Cable
Single-mode Fibre:Carries light pulsesalong single path.
Multi-mode Fibre:Many pulses of lightGenerated by LEDAt different angles.
Single Mode Fibres
Single-mode fibers – used to transmit one signal
per fiber (used in telephone and cable TV). They
have small cores(9 microns in diameter) and
transmit infra-red light from laser.
Multi-mode Fibres
Multi-mode fibers – used to transmit
many signals per fiber (used in
computer networks). They have larger
cores(62.5 microns in diameter) and
transmit infra-red light from LED.
Index Profile
The boundary
between the core
and cladding may
either be abrupt, in
step-index fiber, or
gradual, in
graded-index fiber.
Step-Index
A step-index fiber has a central core with a
uniform refractive index. An outside
cladding that also has a uniform refractive
index surrounds the core;
However, the refractive index of the
cladding is less than that of the central core.
Graded-Index
In graded-index fiber, the index of
refraction in the core decreases
continuously between the axis and the
cladding. This causes light rays to bend
smoothly as they approach the cladding,
rather than reflecting abruptly from the
core-cladding boundary.
Optical Fiber Communication
Fiber Optic Communication
It is a method of transmitting information
from one place to another by sending
light through an optical fiber.
The light forms an electromagnetic
carrier wave that is modulated to carry
information.
Block Diagram of OFC
Total Internal Reflection
Use of OFC in Railways.
To optimize train scheduling.Speed measurement.Signal distribution by FBG.Traffic light monitoring.