project report on transmission

7/30/2019 Project Report on Transmission

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Project ReportOn Transmission


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Overview of OFC. OFC Splicing. Overview of Transmission Technology. Introduction of SDH Technology. Installation and Hardware description. Commissioning of SDH System. Configuration Management. Performance Management. Data Circuit Provisioning. Future scope .

Contents:


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Overview of OFC

Fibre Optics:-

An optical fibre (or optical fibre) is a flexible, transparent fibre made of glass

(silica) or plastic, slightly thicker than a human hair. It functions as a waveguide,

or light pipe , to transmit light between the two ends of the fibre. The field

of applied science and engineering concerned with the design and application of

optical fibres is known as fibre optics.

Information is encoded into electrical signals.

Electrical signals are converted into light signals.

Light travels down the fibre.

A detector changes the light signals into electrical signals.

Electrical signals are decoded into information.

Principle of operation:-

Total Internal Reflection:- The reflection that occurs when a light ray travelling

in one material hits a different material and reflects back into the original

material without any loss of light.
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Advantages of optical fibres over wires

Lower cost in the long run

Low loss of signal (typically less than 0.3 dB/km), so repeater-less

transmission over long distances is possible

Large data-carrying capacity .

Immunity to electromagnetic interference.

No electromagnetic radiation.

High electrical resistance, so safe to use near high-voltage equipment or between areas with different earth potentials

Low weight

Signals contain very little power.

No crosstalk between cables

Difficult to place a tap or listening device on the line, providing better

physical network security

Disadvantages of optical fibres compared to wires

High investment cost

Need for more expensive optical transmitters and receivers

More difficult and expensive to splice than wires

Fibbers can be used as light guides in medical .
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Applications of optical fibres

Optical fibres can be used as sensors to measure strain,temperature, pressure and other parameters.

Bundles of fibres are used along with lenses for long, thin imaging

devices called endoscopes.

A few communities have Fiber to the Home technology which provides

subscribers with Ultra High Speed Internet, Telephone, and Television services.

Transmission sequence:

1. Information is encoded into electrical signals.2. Electrical signals are converted into light signals.3. Light travels down the fiber.4. A detector changes the light signals into electrical signals.5. Electrical signals are decoded into information.
http://en.wikipedia.org/wiki/Fiber_to_the_Homehttp://en.wikipedia.org/wiki/Internethttp://en.wikipedia.org/wiki/Telephonehttp://en.wikipedia.org/wiki/Cable_televisionhttp://en.wikipedia.org/wiki/Cable_televisionhttp://en.wikipedia.org/wiki/Telephonehttp://en.wikipedia.org/wiki/Internethttp://en.wikipedia.org/wiki/Fiber_to_the_Home


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Principle of operation:

Reflection: - It occurs when light rays travelling in one mediumStrikeagainst another material/ medium with different refractive index and

bounce back to the first medium.

5.3.1 Refraction of light: Speed of light is actually the velocity of electromagnetic energy in vacuum such as space. Light travels atslower velocities in other materials such as glass. Light travellingfrom one material to another changes speed, which results in lightchanging its direction of travel. This deflection of light is calledrefraction.

When light travels from lower refractive index to higher refractive index it bends towards normal.

But light going from a higher index to a lower one refracting away from thenormal.


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5.3.2 Critical angle: The angle of incidence for which angle of refraction is 90 0.

6 Snells law: For a given pair of media and wave of single frequency

Sin 1 = n2 = v1

Sin 2 n1 v2

Or

n1sin 1 = n2sin 2

Total internal reflection:

Occurs only if a) n2 < n1 i.e. if light travels from denser to rarer medium b) Angle of incidence is greater than Critical angle


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The light is reflected back to the 1 st medium and doesnt enter the second

medium

When angle of incidence is equal to critical angle i.e. when 1 = c then angleof refraction 2 = 90

o .

Propagation of Light through Fiber:

Optical fiber has two concentric layers

Core The light carrying part

Cladding Surrounds Core

R.I of Cladding < R.I of Core . Allows Total Internal reflection through core.

Total Internal Reflection :

The light striking the core cladding interface at angle greater than criticalangle is reflected back into the core.


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Coating or Buffer coating acts as shock absorber only, doesnt have anyoptical properties.

Since angle of incidence and angle of reflection are equal the reflected lightis again reflected and will keep on reflecting again and again through thelength of the fiber.

The light striking the core cladding interface at angle less than critical angleis passed onto the cladding and is lost over a distance Fiber Geometry

Core: Made up of optically transparent material usually Silica or Borosilicate glass.

Cladding: Material same as that of Core with slightly lower R.I

Diameters o Core (m): 8 to 10 in Single Mode Fiber

50 to 62.5 in multimode fiber


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o Cladding (m): 125Practically:

o Core: 9 m o Cladding: 125 m

Fiber cable has 12 colours at international level:1. Blue2. Orange3. Green4. Brown5. Slate(grey)6. White(milky white)7. Red8. Black 9. Yellow10. Violet11. Pink(rose)12. Aqua (sky blue)(sea water)

Optical Fiber Parameters:

Wavelength:

It is usually determined by considering the distance between consecutivecorresponding points of the same phase, such as crests, troughs, or zerocrossings.

It is a characteristic of the lightsource.

It is measured in nanometer (nm). Frequency:

Number of pulses emitted from a light source per second Measured in hertz (Hz). 1Hz = 1 pulse / S.Window

A window is defined as the range of wavelengths at which the fiber bestoperates

First Window 850 nm ( 800 nm 900 nm) Second Window 1300 nm (1250 nm 1350 nm) Third Window 1550 nm ( 1500 nm 1600 nm)


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Fibre Types:-

By classification:-

Single Mode

Multi-mode

upon refractive index profile:-

Step Index

Single Mode step Index

Multi Mode step Index

Graded Index

Multimode graded Index

Single Mode:-

An optical fiber designed to carry only a single ray of light (mode).

Multi Mode:- large core and also the possibility of large numerical aperture,

multi-mode fiber has higher "light-gathering" capacity than single-mode fiber.

Step Index:-

Step-index fibers have a uniform core with one index of refraction, and a

uniform cladding with a smaller index of refraction. (Air serves as the cladding

in the simple glass tube example.) When plotted on a graph as a function of

distance from the center of the fiber, the index of refraction resembles a step

function
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Graded Index:-

Graded Index Fiber is a type of fiber where the refractive index of the core is

lower toward the outside of the fiber. It bends the rays inward and also allows

them to travel faster in the lower index of refraction region. This type of fiber

provides high bandwidth capabilities.

Optical Fiber Loss and Attenuation

The attenuation of an optical fiber measures the amount of light lost between

input and output. Total attenuation is the sum of all losses.


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Optical losses of a fiber are usually expressed in decibels per ki lometer

(dB/km) . The expression is called the fibers attenuation coefficient and theexpression is

For a given fiber, these losses are wavelength-dependent which is shown in the

figure below. The value of the attenuation factor depends greatly on the fiber

material and the manufacturing tolerances, but the figure below shows a typical

optical fibers attenuation spectral distribution.

The typical fused silica glass fibers we use today has a minimum loss at

1550nm.

Absorption Optical Fiber

Loss Mechanisms
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Absorption is uniform. The same amount of the same material always absorbs

the same fraction of light at the same wavelength. If you have three blocks of thesame type of glass, each 1-centimeter thick, all three will absorb the same

fraction of the light passing through them.

Absorption also is cumulative, so it depends on the total amount of material the

light passes through. If the absorption is 1% per centimeter, it absorbs 1% of the

light in the first centimeter, and 1% of the remaining light the next centimeter,

and so on.

Intrinsic Material Absorption

Intrinsic absorption is caused by interaction of the propagating lightwave with

one more more major components of glass that constitute the fibers material

composition. These looses represent a fundamental minimum to the attainable

loss and can be overcome only by changing the fiber material.

An example of such an interaction is the inf rared absorption band of

SiO 2 shown in the above figure. However, in the wavelength regions of interest

to optical communication (0.8-0.9um and 1.2-1.5um), infrared absorption tails

make negligible contributions.

Extrinsic Impurity Ions Absorption

Extrinsic impurity ions absorption is caused by the presence of minute quantity

of metallic ions (such as Fe 2+, Cu 2+, Cr 3+) and the OH - ion from water dissolved

in glass. The attenuation from these impurity ions is shown in the following

table.


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From the table above, we can see that 1 part per million (ppm) of Fe 2+ would

lead to a loss of 0.68 dB/km at 1.1um. This shows the necessity of ultrapurefibers. Luckily, losses due to the metallic ions can be reduced to very low by

refining the glass mixture to an impurity level below 1 par per billion (ppb).

The OH - ion from water vapor in the glass leads to absorption peaks at 0.72um,

0.88um, 0.95um, 1.13um, 1.24um and 1.38um. The broad peaks at 1.24um and

1.38um in the first figure cure are due to OH - ion. The good news is OH - ion

absorption band is narrow enough that ultrapure fibers can achieve losses less

than 0.2 dB/km at 1.55um.

With new manufacturing techniques, we can reduce the OH - ion content to

below 1 part per billion (ppb). The results are ultra-low-loss fibers which have a

wider low-loss window in silica glass fibers shown in the following figure. This

improvement enables the use of WDM technology in fiber optic networks,which dramatically increased the capacity of fiber optic systems.

Scattering
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Scattering losses occur when a wave interacts with a particle in a way that

removes energy in the directional propagating wave and transfers it to other directions. The light isnt absorbed, just sent in another direction. However, the

distinction between scattering and absorption doesnt matter much because the

light is lost from the fiber in either case.

There are two main types of scattering:

Linear scattering Nonlinear scattering .

For linear scattering , the amount of light power that is transferred from a wave

is proportional to the power in the wave. It is characterized by having no change

in frequency in the scattered wave.On the other hand, nonlinear scattering is

accompanied by a frequency shift of the scattered light. Nonlinear scattering is

caused by high values of electric field within the fiber (modest to high amount

of optical power). Nonlinear scattering causes significant power to be scattered

in the forward, backward, or sideways directions.

Rayleigh Scattering (Linear Scattering)

Rayleigh scattering (named after the British physicist Lord Rayleigh) is the main

type of linear scattering. It is caused by small-scale (small compared with the

wavelength of the lightwave) inhomogeneities that are produced in the fiber

fabrication process. Examples of inhomogeneities are glass composition

fluctuations (which results in minute refractive index change) and density

fluctuations (fundamental and not improvable). Rayleigh scattering accounts for

about 96% of attenuation in optical fiber.


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As light travels in the core, it interacts with the silica molecules in the core.

These elastic collisions between the light wave and the silica molecules result inRayleigh scattering. If the scattered light maintains an angle that supports

forward travel within the core, no attenuation occurs. If the light is scattered at

an angle that does not support continued forward travel, the light is diverted out

of the core and attenuation occurs. Depending on the incident angle, some

portion of the light propagates forward and the other part deviates out of the

propagation path and escapes from the fiber core. Some scattered light isreflected back toward the light source. This is a property that is used in an

OTDR (Optical Time Domain Reflectometer) to test fibers.

Rayleigh scattering describes the elastic scattering of light by particles which aremuch smaller than the wavelength of light. The intensity of the scattered

radiation is given by

Rayleigh scattering depends not on the specific type of material but on the size

of the particles relative to the wavelength of light. The loss due to Rayleigh

scattering is proportional to -4 and obviously decreases rapidly with increase in

wavelength (see the first figure above Loss vs.. Wavelength). Short
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wavelengths are scattered more than longer wavelengths. Any wavelength that is

below 800nm is unusable for optical communication because attenuation due toRayleigh scattering is too high.

Mie Scattering (Linear Scattering)

Mie scattering is named after German physicist Gustav Mie. This theory

describes scattering of electromagnetic radiation by particles that are

comparable in size to a wavelength (larger than 10% of wavelength).

For particles much larger, and much smaller than the wavelength of scattered

light there are simple and excellent approximations that suffice.

For glass fibers, Mie scattering occurs in inhomogeneities such as core-cladding

refractive index variations over the length of the fiber, impurities at the core-

cladding interface, strains or bubbles in the fiber, or diameter fluctuations.

Mie scattering can be reduced by carefully removing imperfections from the

glass material, carefully controlling the quality and cleanliness of the

manufacturing process.

In commercial fibers, the effects of Mie scattering are insignificant. Optical

fibers are manufactured with very few large defects. (larger than 10% of wavelength)

Brillouin Scattering (Nonlinear Scattering)

Brillouin scattering is caused by the nonlinearity of a medium. In glass fibers,

Brillouin scattering shows as a modulation of the light by the thermal energy in

the material.


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An incident photon can be converted into a scattered photon of slightly lower

energy, usually propagating in the backward direction, and a phonon (vibrational

energy). This coupling of optical fields and acoustic waves occurs via

electrostriction.

The frequency of the reflected beam is slightly lower than that of the incident

beam; the frequency difference v B corresponds to the frequency of emitted phonons. This is called Brillouin Frequency Shift. This phenomenon has been

used for fiber optic sensor applications.

Brillouin scattering can occur spontaneously even at low optical powers. This is

different than Stimulated Brillouin Scattering which requires optical power to

meet a threshold high enough to happen.

Above a certain threshold power, stimulated Brillouin scattering can reflect most

of the power of an incident beam. The optical power level at which stimulated
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Brillouin scattering becomes significant in a single mode fiber is given by the

empirical formula below.

Stimulated Raman Scattering (Nonlinear Scattering)

Stimulated Raman scattering is a nonlinear response of glass fibers to the optical

intensity of light. This is caused by vibrations of the crystal (or glass) lattice.

Stimulated Raman scattering produces a high-frequency optical phonon, as

compared to Brillouin scattering, which produces a low-frequency acoustical phonon, and a scattered photon.

When two laser beams with different wavelengths (and normally with the same

polarization direction) propagate together through a Raman-active medium, the

longer wavelength beam can experience optical amplification at the expense of

the shorter wavelength beam. This phenomenon has been used for Raman

amplifiers and Raman lasers.

Macrobending Loss

Macrobending happens when the fiber is bent into a large radius of curvature

relative to the fiber diameter (large bends). These bends become a great sourceof power loss when the radius of curvature is less than several


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centimeters.Macrobend may be found in a splice tray or a fiber cable that has

been bent. Macrobend wont cause significant radiation loss if it ha s largeenough radius.However, when fibers are bent below a certain radius, radiation

causes big light power loss as shown in the figure below.

Microbending Loss

Microbendings are the small-scale bends in the core-cladding interface. These

are localized bends can develop during deployment of the fiber, or can be due to

local mechanical stresses placed on the fiber, such as stresses induced by cabling

the fiber or wrapping the fiber on a spool or bobbin.

Microbends can cause 1 to 2 dB/km losses in fiber cabling process.

OFC Splicing

Splices are permanent connection between two fibers. The splicing involvescutting of the edges of the two fibers to be spliced.

Splicing Methods:
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The following three types are widely used:

1. Adhesive bonding or Glue splicing.

2. Mechanical splicing.

3. Fusion splicing.

1. Adhesive Bonding or Glue Splicing:

This is the oldest splicing technique used in fiber splicing. After fiber end preparation, it is axially aligned in a precision V groove. Cylindrical rods or another kind of reference surfaces are used for alignment. During the alignmentof fiber end, a small amount of adhesive or glue of same refractive index as thecore material is set between and around the fiber ends. A two component epoxyor an UV curable adhesive is used as the bonding agent. The splice loss of thistype of joint is same or less than fusion splices. But fusion splicing technique ismore reliable, so at present this technique is very rarely used.

2. Mechanical Splicing:

This technique is mainly used for temporary splicing in case of emergencyrepairing. This method is also convenient to connect measuring instruments to

bare fibers for taking various measurements.

3. Fusion Splicing:

The fusion splicing technique is the most popular technique used for achievingvery low splice losses. The fusion can be achieved either through electrical arcor through gas flame.

The process involves cutting of the fibers and fixing them in micro positionerson the fusion splicing machine. The fibers are then aligned either manually or automatically core aligning (in case of S.M.fiber) process. Afterwards theoperation that takes place involve withdrawal of the fibers to a specifieddistance, preheating of the fiber ends through electric arc and bringing together of the fiber ends in a position and splicing through high temperature fusion.

o Operation of fusion splicer:Splicer Operation: It is awkward at first to hold, strip, cleave and place the fiber in the clamps.


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Practice makes perfect. Here are five general steps to complete a fusionsplice:

1. Strip, Clean, & Cleavea. Strip

Strip fiber to appropriate length per your splicer's instruction manual.

b. Cleaning

Clean the fiber with Fiber-Clean towelettes or a lint-free wipe and isopropylalcohol so that the fiber squeaks.

c. Cleaving

Place fiber (after stripping and cleaning it) in cleaver using the fiber guide to position it

Align the fiber in the cleave area to cleave at the proper length Depress the cleaver arm gently Remove and safely discard the fiber scrap


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2. Load Splice

Position tip of fiber near electrodes Do not bump tips into anything Ease placement by bowing fibers in groove.

3. Splice Fibers

READ The Manual! WATCH The Video (M90, X77, miniMASS and FuseLite available) PRACTICE! Don't expect to be a pro after one splice Place first cleaved fiber in v-groove with fiber tip near the electrodes Close the fiber clamps Repeat on opposite side for second fiber

Select program on fusion splicer Initiate fuse cycle (can be manual or automatic)

4. Diagnose and Correct If Errors Occur

Cleaver - wipe blade and clamps periodically - operate slowly; it's not astapler!

Alignment - clean V-grooves, guides, clamps when offsets occur Electrodes - clean at the start of each day; Video System - clean LEDs, prisms/mirrors, cameras, and protective disk

High Loss - fibers not aligned, poor geometry, dirty electrodes, or wrong parameters

Multimode fiber - bubbles and neck downs are frequent occurrences: expectabout 80% yield on most splicers

Titan fiber - difficult to cleave: deeper score, splices hotter: reduce currentsettings for ribbon

A "Good Splice" is determined by:- User Skill: cleanliness, operation of equipment, ability to recognize andcorrect poor preconditions

- Splicer: V-groove, cladding alignment vs. core alignment, proper settings- Fiber: good geometry quality


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5. Remove and Protect Splice

Remove completed splice from splice area Use Heat-Shrink oven (or mechanical protection) to protect the splice Place splice tray in adjustable tray holder and insert protected splice into

splice tray.


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Overview of Transmission Technology

1) PCM (Pulse code Modulation)

2) PDH (Plesiochronous digital hierarchy)

3) SDH (synchronous Digital Hierarchy)

PCM (Pulse code Modulation):-

It was only in 1938 Mr.A.M. Reaves (USA) developed a pulse codemodulation (PCM) system to transmit the spoken word in digital form.Since the digital speech transmission has become an alternative to theanalog system.

PCM system use TDM technique to provide a number of circuits on thesame transmission medium via open wire or underground cable pair or acannel provided by carrier, coaxial, microwave or satellite system.

Basic requirements for PCM system

To develop a PCM signal from several analog signals, the processingsteps are requireda) Filtering

b) Samplingc) Quantizationd) Compandinge) Encodingf) Multiplexingg) Line coding

a) Filtering: filters are used to limit the speech signal to the frequency band300-3400 Hz. b) Sampling: In signal processing, sampling is the reduction of a continuous

signal to a discrete signal. A common example is the conversion of a soundwave (a continuous signal) to a sequence of samples (a discrete-time signal).

Sample: A sample refers to a value or set of values at a point in time or space.

Sampler: It is a subsystem or operation or subsystem that extracts

samples from continuous signal.
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A theoretical ideal sampler produces samples equivalent to theinstantaneous value of the continuous signal at the desired points.

Sampling Theorem: If a band limited signal is sampled at regular intervalof time and at a rate equal to more than twice the highest signal frequency in the

band, then the sample contains all the information of the original signal.Mathematically, if fH is the highest frequency in the signal to be sampled thenthe sampling frequency Fs needs to be greater than 2fH.

I.e. Fs>2fH

For e.g. - Let us say our voice signals are band limited to 4 KHz and letsampling frequency be 8 KHz.

Time period of sampling Ts= 1sec/8000

Or Ts= 125 micro seconds.Types of sampling: sampling is of two types:

1) Natural sampling : Top of signal is just replica of incoming signal. 2) Flat-top sampling: In this we use sample and hold circuit. Top of signal

is flat that is why it is known as flat-top sampling.

Flat-top sampling


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Sample and hold circuit

c) Quantization: Assigning standard, specific or unique value or round off value.Or to provide particular / finite voltage level.

Or in mathematics and digital signal processing, is the process of mapping largeset of input values to a smaller set- such as rounding values to some unit of

precision.

Quantizer : A device or algorithmic function that performs quantization is calledquantizer.

. Sampled signal (discrete signal ): discrete time,

continuous values. Quantized signal: continuous time, discrete values.

Steps for quantization:

Divide each sample into steps. Before quantization there may be infinite value. After quantization there are only finite values. PCM system assigns the lower value of the step. Decoder at receiving end always decodes the middle value of the level.

Quantization error: The error introduced by quantization is referred to asquantization error or round-off error.

Q.E= transmitted value- receiving value

If transmitted value= 3.9
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And receiving value =3.5

Then Q.E= transmitted value- receiving value

Q.E=3.9-3.5=0.4

Maximum quantization error: It is defined as half of the step size.

Q.E max = s/2 = step size/2

If step size= 1 then

Q.E max = s/2 = = 0.5

To check quality: We use SNR (signal to noise ratio). If we want good qualitythen the value of SNR must be high.

If we require high SNR then Q.E must be low.

Q.E must be reduced by reducing/ decreasing the step size. If we reduce the step size then another problem is the number of levelsincreases due to that there is problem of coding due to that bit rateincreases.

Practically PCM divides into 256 levels or steps.

d) Companding: This is non-linear quantization. It compresses signal attransmitting end and expand signal at receiving end. Or shortening the step size for lower level signal and widening the step sizefor higher level signal.


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Original signal After compressing, before expanding

There are two laws of companding:

1) A law of companding.2) law of companding.

e) Encoding:Conversion of quantized analog levels to binary signal is called as encoding.

To represent 256 steps, 8 level code is required. The 8 bit code is also an 8 bit word.

The 8 bit word appears in the form

P ABC WXYZPolarity bit Segment bits Q.I.identification

1 for +ve bits0 for -ve

1 bit 3 bits 4 bits

Encoding

Segment Number Range of Segment Step Size0 0-31 2vp1 32-63 2vp2 64-127 4vp3 128-255 8vp4 256-511 16vp5 512-1023 32vp6 1024-2047 64vp7 2048-4095 128vp

Foe examples: Encoding of +280vp

1) +280vp is +ve so first of all we have to find value of PThe value of P is 1 for +ve value


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So P=12) It lies in 4 th segment

Find binary equivalent for 4, it is 100So value of ABC=100

3) As it lies in 4 th segment it has range 256-511Its step size is 16. So divide it into 16 intervals to find Q.I. (quantizationinterval). Like 256-271, 272-287 and so on.

It lies in 1 st interval starting from 0.

Binary equivalent of 1 is 0001, so value of WXYZ is 0001.

So encoding of +280vp is

P ABC WXYZ

1 100 0001

f) Multiplexing:

It is defined as transmission of multiple messages simultaneously.There are following types of multiplexing techniques:FDM (Frequency Division Multiplexing)

TDM (Time Division Multiplexing)

g) Line coding:Line codec chips converts the encoded signal into HDB code which iscompatible for transmit over channel.

Concept of FRAME:

One full set of samples for all channels taken with the duration Ts is called aframe. The set of second samples of all channels is one frame. Where Ts is timeslot.

In PCM system there are 32 time slots and 30 channels. Ts in a 30 channelPCM system is 125 microseconds and the signaling information of all the


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channels is transmitted through separate time slot. To maintain synchronization between transmit and receive ends, the synchronization data is transmittedthrough another time slot. Thus for 30 channel PCM system we have 32 timeslots

Thus the time available per channel would be 3.9 microseconds.

Thus for 30 channel PCM system,

Frame= 125 microseconds

Time slot per channel=3.9 microseconds.

Structure of frame:

A frame of 125 microseconds duration has 32 time slots. These slots arenumbered Ts0 to Ts31.

Information for providing synchronization between trans and receive ends is

passed through a separate time slot. Usually the slot Ts0 carries thesynchronization signals. This slot is also called frame alignment word (FAW).

The signaling information is transmitted through slot Ts16.

Ts1 to Ts15 are utilized for voltage signal of channels 1 to 15 respectively.

Ts17 to Ts31 are utilized for voltage signal of channels 16 to 30 respectively.

Synchronization: The output of PCM terminal will be a continuous stream of bits. At the receiving end, the receiver has to receive the incoming stream of bitsand discriminate between frames and separate channels from these. That iscalled frame alignment or synchronization and is achieved by inserting a fixeddigital pattern called a frame alignment word (FAW) into the transmitted bitstream at regular intervals. The receiver looks for FAW and once it is detected,it knows that in next time slot, information for channel one will be there and soon.


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The digits or bits of FAW occupy seven out of eight bits of Ts0 in thefollowing pattern.

Bits position of Ts0 B1 B2 B3 B4 B5 B6 B7 B8

FAW digit value X 0 0 1 1 0 1 1

The bit position B1 can be either 1 or 0. However when the PCM systemis to be linked with an international network, the B1 position is fixed at 1.

The FAW is transmitted in the Ts0 of every alternate frame. Frames which do not contain the FAW are used for transmitting supervisory

and alarm signals.

To distinguish the Ts0 frame carrying supervisory/alarm signals from thosecarrying the FAW, the B2 bit position of the former are fixed at T. the FAWand alarm signals are transmitted alternatively as shown in following table-2:TABLE-2

FrameRemarks

Numbers B1 B2 B3 B4 B5 B6 B7 B8F0 X 0 0 1 1 0 1 1 FAWF1 X 1 Y Y Y 1 1 1 ALARMF2 X 0 0 1 1 0 1 1 FAWF3 etc X 1 Y Y Y 1 1 1 ALARM

In frames 1, 3, 5 etc the bits B3, B4, B5 denote various types of alarms. For example, in B3 position, if Y=1, it indicates frame synchronization alarm. If Y=1 in B4, in indicates high error density alarm. When there is no alarm

condition, bits B3, B4, B5 are set 0. An urgent alarm is indicated bytransmitting all ones. The code word for an urgent alarm would be theform:

X 111 1111.

Signaling in PCM system:

In telephone network the signaling information is used for proper routing of acall between two subscribers, for providing certain status information like dialtone, busy tone, ring back, NU tone, metering pulses, trunk offering signals etc.


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all these functions are grouped under general term signaling in PCM system.The signaling information can be transmitted in the form of DC pulses or multifrequency pulses.

The signaling pulses retain their amplitude for a much longer period than the pulses carrying speech information. It means that signaling information is aslow varying signal in the time compared to speech signal which is fastchanging in the time domain. Therefore a signaling channel can be digitizedwith less number of bits than a voice channel.

In 30 channel PCM system, time slot Ts16 in each frame is allocated for carrying signaling information.

The time slot 16 of each frame carries the signaling data corresponding totwo VF channels only. Therefore to cater for 30 channels we must frames,each having 125 microseconds duration. For carrying synchronization datafor all frames, one additional frame is used. Thus a group of 16 frames (eachof 125 microseconds) is formed to make a multiframe. The duration of amultiframe is 2 milliseconds. The multiframe has 16 major time slots of 125microsecond duration. Each of these (slots) frames has 32 time slots carrying.The encoded samples of all channels plus the signaling and synchronizationdata. Each sample has 8 bits of duration 0.400 microseconds (3.9/8=0.488)each.

We have 32 time slots in a frame; each slot carries an 8 bit word. Total number of frames per second is 8000. The total number of bits per second is 256*8000=2048k/bits.

Thus, a 30 channel PCM system has 2048 K bits.

Limitations of PCM:

There are potential sources of impairment implicit in any PCM system:

Choosing a discrete value that is near but not exactly at the analog signallevel for each sample leads to quantization error .

Between samples no measurement of the signal is made; the samplingtheorem guarantees non-ambiguous representation and recovery of the signalonly if it has no energy at frequency f s/2 or higher (one half the samplingfrequency, known as the Nyquist frequency ); higher frequencies willgenerally not be correctly represented or recovered.
http://en.wikipedia.org/wiki/Quantization_errorhttp://en.wikipedia.org/wiki/Quantization_errorhttp://en.wikipedia.org/wiki/Quantization_errorhttp://en.wikipedia.org/wiki/Sampling_theoremhttp://en.wikipedia.org/wiki/Sampling_theoremhttp://en.wikipedia.org/wiki/Sampling_theoremhttp://en.wikipedia.org/wiki/Sampling_theoremhttp://en.wikipedia.org/wiki/Nyquist_frequencyhttp://en.wikipedia.org/wiki/Nyquist_frequencyhttp://en.wikipedia.org/wiki/Nyquist_frequencyhttp://en.wikipedia.org/wiki/Nyquist_frequencyhttp://en.wikipedia.org/wiki/Sampling_theoremhttp://en.wikipedia.org/wiki/Sampling_theoremhttp://en.wikipedia.org/wiki/Quantization_error


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As samples are dependent on time, an accurate clock is required for accurate

reproduction. If either the encoding or decoding clock is not stable, itsfrequency drift will directly affect the output quality of the device.

PDH (Plesiochronous digital hierarchy):-

The plesiochronous digital hierarchy (PDH) is a technology used

in telecommunications networks to transport large quantities of data over digitaltransport equipment such as fibre optic and microwave radio systems. The

term plesiochronous is derived from Greek plsios , meaning near, and chronos ,

time, and refers to the fact that PDH networks run in a state where different parts

of the network are nearly, but not quite perfectly, synchronised.

PDH is typically being replaced by synchronous digital hierarchy (SDH) or

synchronous optical networking (SONET) equipment in mosttelecommunications networks.

PDH allows transmission of data streams that are nominally running at the same

rate, but allowing some variation on the speed around a nominal rate. By

analogy, any two watches are nominally running at the same rate, clocking up

60 seconds every minute. However, there is no link between watches to

guarantee they run at exactly the same rate, and it is highly likely that one isrunning slightly faster than the other.

Implementation:- The data rate is controlled by a clock in the equipment

generating the data. The rate is allowed to vary by 50 ppm of 2.048 Mbit/s.

This means that different data streams can be (probably are) running at slightly

different rates to one another.
http://en.wikipedia.org/wiki/Telecommunications_networkhttp://en.wikipedia.org/wiki/Fibre_optichttp://en.wikipedia.org/wiki/Microwave_radiohttp://en.wikipedia.org/wiki/Plesiochronoushttp://en.wikipedia.org/wiki/Plesiochronoushttp://en.wikipedia.org/wiki/Plesiochronoushttp://en.wikipedia.org/wiki/Synchronisedhttp://en.wikipedia.org/wiki/Synchronous_digital_hierarchyhttp://en.wikipedia.org/wiki/Synchronous_digital_hierarchyhttp://en.wikipedia.org/wiki/Synchronisedhttp://en.wikipedia.org/wiki/Plesiochronoushttp://en.wikipedia.org/wiki/Microwave_radiohttp://en.wikipedia.org/wiki/Fibre_optichttp://en.wikipedia.org/wiki/Telecommunications_network


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In order to move multiple data streams from one place to another, they are

multiplexed in groups of four. This is done by taking 1 bit from stream #1,followed by 1 bit from stream #2, then #3, then #4. The

transmitting multiplexer also adds additional bits in order to allow the far end

receiving multiplexer to decode which bits belong to which data stream, and so

correctly reconstitute the original data streams. These additional bits are called

"justification" or "stuffing" bits.

Because each of the four data streams is not necessarily running at the same rate,some compensation has to be introduced. The transmitting multiplexer combines

the four data streams assuming that they are running at their maximum allowed

rate. This means that occasionally, (unless the 2 Mbit/s really is running at the

maximum rate) the multiplexer will look for the next bit but it will not have

arrived. In this case, the multiplexer signals to the receiving multiplexer that a

bit is "missing". This allows the receiving multiplexer to correctly reconstructthe original data for each of the four 2 Mbit/s data streams, and at the correct,

different, plesiochronous rates.

The resulting data stream from the above process runs at 8.448 Mbit/s (about

8 Mbit/s). Similar techniques are used to combine four 8 Mbit/s together,

plus bit stuffing, giving 34 Mbit/s. Four 34 Mbit/s, gives 140. Four 140

gives 565.

565 Mbit/s is the rate typically used to transmit data over a fibre optic system for

long distance transport. Recently, [when? ] telecommunications companies have

been replacing their PDH equipment with SDH equipment capable of much

higher transmission rates.

SDH(Synchronous Digital Hierarchy (SDH):-
http://en.wikipedia.org/wiki/Multiplexerhttp://en.wikipedia.org/wiki/Bit_stuffinghttp://en.wikipedia.org/wiki/Bit_stuffinghttp://en.wikipedia.org/wiki/Wikipedia:Manual_of_Style/Dates_and_numbers#Chronological_itemshttp://en.wikipedia.org/wiki/Wikipedia:Manual_of_Style/Dates_and_numbers#Chronological_itemshttp://en.wikipedia.org/wiki/Wikipedia:Manual_of_Style/Dates_and_numbers#Chronological_itemshttp://en.wikipedia.org/wiki/Wikipedia:Manual_of_Style/Dates_and_numbers#Chronological_itemshttp://en.wikipedia.org/wiki/Bit_stuffinghttp://en.wikipedia.org/wiki/Bit_stuffinghttp://en.wikipedia.org/wiki/Multiplexer


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Synchronous Optical Networking (SONET) and Synchronous Digital

Hierarchy (SDH) are standardized protocols that transfer multiple digital bitstreams over optical fiber using lasers or highly coherent light from light-

emitting diodes (LEDs). At low transmission rates data can also be transferred

via an electrical interface. The method was developed to replace

the Plesiochronous Digital Hierarchy (PDH) system for transporting large

amounts of telephone calls and data traffic over the same fiber without

synchronization problems. SONET and SDH, which are essentially the same,were originally designed to transport circuit mode communications

(e.g., DS1, DS3 ) from a variety of different sources, but they were primarily

designed to support real-time, uncompressed, circuit-switched voice encoded

in PCM format. The primary difficulty in doing this prior to SONET/SDH was

that the synchronization sources of these various circuits were different. This

meant that each circuit was actually operating at a slightly different rate and

with different phase. SONET/SDH allowed for the simultaneous transport of

many different circuits of differing origin within a single framing protocol.

SONET/SDH is not itself a communications protocol per se , but a transport

protocol.

Due to SONET/SDH's essential protocol neutrality and transport-oriented

features, SONET/SDH was the obvious choice for transporting the fixed

length Asynchronous Transfer Mode (ATM) frames also known as cells. It

quickly evolved mapping structures and concatenated payload containers to

transport ATM connections. In other words, for ATM (and eventually other

protocols such as Ethernet) , the internal complex structure previously used to

transport circuit-oriented connections was removed and replaced with a large

and concatenated frame (such as STS-3c) into which ATM cells, IP packets, or

Ethernet frames are placed.
http://en.wikipedia.org/wiki/Digitalhttp://en.wikipedia.org/wiki/Optical_fiberhttp://en.wikipedia.org/wiki/Laserhttp://en.wikipedia.org/wiki/Coherence_(physics)http://en.wikipedia.org/wiki/Light-emitting_diodehttp://en.wikipedia.org/wiki/Light-emitting_diodehttp://en.wikipedia.org/wiki/Plesiochronous_Digital_Hierarchyhttp://en.wikipedia.org/wiki/Telephonehttp://en.wikipedia.org/wiki/Datahttp://en.wikipedia.org/wiki/Circuit_modehttp://en.wikipedia.org/wiki/Digital_Signal_1http://en.wikipedia.org/wiki/Digital_Signal_3http://en.wikipedia.org/wiki/PCMhttp://en.wikipedia.org/wiki/Asynchronous_Transfer_Modehttp://en.wikipedia.org/wiki/Ethernethttp://en.wikipedia.org/wiki/Ethernethttp://en.wikipedia.org/wiki/Asynchronous_Transfer_Modehttp://en.wikipedia.org/wiki/PCMhttp://en.wikipedia.org/wiki/Digital_Signal_3http://en.wikipedia.org/wiki/Digital_Signal_1http://en.wikipedia.org/wiki/Circuit_modehttp://en.wikipedia.org/wiki/Datahttp://en.wikipedia.org/wiki/Telephonehttp://en.wikipedia.org/wiki/Plesiochronous_Digital_Hierarchyhttp://en.wikipedia.org/wiki/Light-emitting_diodehttp://en.wikipedia.org/wiki/Light-emitting_diodehttp://en.wikipedia.org/wiki/Coherence_(physics)http://en.wikipedia.org/wiki/Laserhttp://en.wikipedia.org/wiki/Optical_fiberhttp://en.wikipedia.org/wiki/Digital


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Racks of Alcatel STM-16 SDH add-drop multiplexers

Difference from PDH

SDH differs from Plesiochronous Digital Hierarchy (PDH) in that the exact rates

that are used to transport the data on SONET/SDH are

tightly synchronized across the entire network, using atomic clocks.

This synchronization system allows entire inter-country networks to operatesynchronously, greatly reducing the amount of buffering required between

elements in the network.

Both SONET and SDH can be used to encapsulate earlier digital transmission

standards, such as the PDH standard, or they can be used to directly support

either Asynchronous Transfer Mode (ATM) or so-called packet over

SONET/SDH (POS) networking. Therefore, it is inaccurate to think of SDH or SONET as communications protocols in and of themselves; they are generic, all-
http://en.wikipedia.org/wiki/Alcatelhttp://en.wikipedia.org/wiki/Add-drop_multiplexerhttp://en.wikipedia.org/wiki/Plesiochronous_Digital_Hierarchyhttp://en.wikipedia.org/wiki/Synchronization_(computer_science)http://en.wikipedia.org/wiki/Atomic_clockhttp://en.wikipedia.org/wiki/Synchronization_in_telecommunicationshttp://en.wikipedia.org/wiki/Encapsulation_(computer_science)http://en.wikipedia.org/wiki/Packet_over_SONET/SDHhttp://en.wikipedia.org/wiki/Packet_over_SONET/SDHhttp://en.wikipedia.org/wiki/File:SDH_Racks.jpghttp://en.wikipedia.org/wiki/File:SDH_Racks.jpghttp://en.wikipedia.org/wiki/File:SDH_Racks.jpghttp://en.wikipedia.org/wiki/File:SDH_Racks.jpghttp://en.wikipedia.org/wiki/Packet_over_SONET/SDHhttp://en.wikipedia.org/wiki/Packet_over_SONET/SDHhttp://en.wikipedia.org/wiki/Encapsulation_(computer_science)http://en.wikipedia.org/wiki/Synchronization_in_telecommunicationshttp://en.wikipedia.org/wiki/Atomic_clockhttp://en.wikipedia.org/wiki/Synchronization_(computer_science)http://en.wikipedia.org/wiki/Plesiochronous_Digital_Hierarchyhttp://en.wikipedia.org/wiki/Add-drop_multiplexerhttp://en.wikipedia.org/wiki/Alcatel


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purpose transport containers for moving both voice and data. The basic format

of a SONET/SDH signal allows it to carry many different services in its virtualcontainer (VC), because it is bandwidth-flexible.


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Introduction to SDH technology

SDH-Introduction:-

SDH (Synchronous Digital Hierarchy):-

Is an international standard for high speed telecommunication over

optical/electrical networks ,can transport digital signals.

SYNCHRONOUS :

ONE MASTER CLOCK & ALL ELEMENTS SYNCHRONISE

WITH IT

DIGITAL:

INFORMATION IN BINARY.

HIERARCHY:

SET OF BIT RATES IN A HIERARCHIAL ORDER

ATTEMPTS TO FORMULATE STANDARDS FOR

TRANSMISSION OF SYNCHRONOUS SIGNALS BEGAN

IN U.S. AT THE BEGINNING OF 1984, BY ANSI

ACCREDITED T1X1 COMMITTEE.

IN 1985 SONET ( STANDARD OPTICAL NETWORK)WAS

BORN.

CCITT PROPOSED CHANGES TO T1X1 COMMITTEEIN 1986 TO ACCOMMODATE BOTH AMERICAN AND

EUROPEAN HIERARCHIES.

FINAL AGREEMENT WAS REACHED IN 1988 AND

CCITT WORKING GROUP-XVIII CAME OUT WITH

RECOMMENDATIONS ON SDH.

Limitations of PDH:-


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NON STANDARD EXPERIENCES:

THREE DIFFERENT HIERARCHIES WITH DIFFERENT SIGNAL FORMATS

o BASIS OF TODAYS HIGH CAPACITY NETWORK

o NETWORK REQUIREMENT

o POINT-TO-POINT TRANSMISSION MANUAL APPROACH

TO NETWORK MANAGEMENT AND MAINTENANCE

.

SDH- ADVANTAGES:- SIMPLIFICATION (ABILITY TO DIRECTLY

DROP LOWER TRIB)

CAN ACCOMMODATE BOTH EXISTING AND FUTURE SIGNALS

IMPROVED SERVICE QUALITY (THROUGH SUPERVISION )

ADVANCED N/W MANAGEMENT AND MTCE CAPABILITIES.

N/W SURVIVABILITY

DYNAMIC N/W CAPACITY MANAGEMENT

MULTI VENDOR NETWORKING (MID FIBRE MEET)

PDH HIERARCHIES:-


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ALTTC/TX-1/SDH(I,O&M)/SDH_Concepts

SIGNAL HIERARCHY:-

SONET v/s SDH BIT RATES

BIT RATE : STM-N:-

NUMBER OF ROWS = 9


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NUMBER OF COLUMNS = 9+261=270

NUMBER OF BYTES = 9x270

NUMBER OF BITS = 9x270x8

NUMBER OF BITS / SECOND = 9x270x8x8000

=155520000

=155.520 Mbps (STM-1)

BIT RATE OF STM-N = (Nx155.520) Mbps

MULTIPLEXING Structure:-

Reduced MUX Structure:-


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SDH-Structure

The Container (C)

Basic packaging unit for tributary signals (PDH)

Synchronous to the STM-1

Bitrate adaptation is done via a positive stuffing procedure

Adaptation of synchronous tributaries by fixed stuffing bits

Bit by bit stuffing

The Virtual Container (VC)

Formation of the Container by adding of a POH (Path Overhead)

Transport as a unit through the network (SDH)

A VC containing several VCs has also a pointer area

The Tributary Unit (TU)


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Is formed via adding a pointer to the VC

The Tributary Unit Group (TUG)

Combines several TUs for a new VC

The Administrative Unit (AU)

Is shaped if a pointer is allocated to the VC formed at last

The Syncronous Transport Module Level 1 (STM-1)

Formed by adding a Section Overhead (SOH) to AUs

Clock justification through positive-zero-negative stuffing in the AU pointer

area byten by byte stuffing.


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MUX Principle:Containers (C-n):-

MUX PRINCIPLE: TU-n/ AU:-

It is an information structure which provides adaptation between two layers

between lower and higher order path layers for TU

between higher order path layer and section layer for AU

Pointer is an indicator whose value defines the frame offset of a VC with

respect to the frame refrence of the transport on which it is supported


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MUX Principle: STM-1(from C-4):-

MUX Principle: STM-1(from C-1):-


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MUX Principle:STM-1(from C-4 ):-

MUX Principle:STM-1(from C-3):-


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MULTIPLEXING FROM C-4:-

SECTION OVERHEAD Details:-


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NETWORK ELEMENTS:-

ADD & DROP MULTIPLEXER (ADM):-

PERMITS ADD& DROP OF LOWER ORDER SIGNALS.


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SYNCHRONOUS DIGITAL CROSS CONNECT (SDXC):

PERMITS SWITCHING OF TRANSMISSION LINES WITH

DIFFERENT BIT-RATES.

SDXC CAN ADD AND DROP LOWER-ORDER SIGNALS.

SYNCHRONOUS REGENERATOR (REG):-

REGENERATES THE INCOMING LINE SIGNAL.

SUPERVISE THE TRANSMISSION QUALITY OF THE LINE


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SYNCHRONOUS CROSS CONNECT:-


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Installation & Hardware Description of STMs

Primary Requirements

The rack unit requirement

TJ100LT -- 1 Unit STM-1

TJ100MC1 . 3 Unit STM-1


TJ100MC4L . 11 Unit STM-4 (with Ethernet)


TJ100MC16X -- 14 Unit STM-16 (with Ethernet)

Site preparation

The power supply requirements for system :

AC- 230/110 V 50/60Hz +/. 10%

DC Input- -39 to -60V DC from SMPS Power plant and

MFC batteries

DC Earthing (Ring type 0.5 Ohm resistive max.)

Circuit breaker 2A (MCB may be provided separate

for each system

Primary Requirements

Rack Installation

ensure that the rack is not overly congested,

because each unit generates heat. An enclosed

rack should have lowered sides and a fan to

provide cooling air

Dust free environment : Adequate space and adequate air

circulation


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no direct entry of the dust from the outer environment

Temperature requirement : Optimum 18 to 23 degree cellcious(Maximum Temp. should not be 40 degree cellcious) Air fan should

be

always operated in the equipment itself for circulating the heat

generated.

and should be approved by the competent authority

Preparation before installationHandling/Installing/Scoring or replacing cards and pluggable

module requires

a. Wear wrist strict

b. Not to touch solder side of the any module, pin configuration

or any component

c. Inspect module and pin connectors for any damage

d. Store uninstalled cards in shielded box/plastic wrapper

Flexibility to jack in any card in any of the tributary slot

e. Put the cap on all optical port unused/un fiber.

Choose cards based on requirement

Installation

Following guidelines should be observed during installation Place the NE in 19 inch rack and bolted with 8 no. of MS screw with first

NE at the lowest possible position of rack

Connect Rack should be properly bolted to the leveled ground the ground

point

Connect the DC power with help of plug in power cable to the power

supply connector and the cable securely along left side of the rack andconnect it to the PDP


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Power connector pin configuration: Pin no 1 +ve with red color of strand

of cablePin no 2 Ground green color strand of cable

Pin no 3 -ve blue color strand of cable

Fiber patch card routing it should be left side of the rack

Orderwire cable the RJ45 connector with 8 pin 4&5 used only

Clock cable it is nine way having D type connectivity on XCC card BITS

Interfaces Alarm Cable 7 no of twisted their with 15 way D type connector in MFC

NMS cable it is cross/straight (if hub is used) with RJ45 connector to the

NMS port in the MFC

Craft / modem cable : 9 pin RS 232 type serial cable (female) to be

connected to the serial port 1 & 2 on MFC

48 volt earthing cable : it is the single strand cooper cable used for +vesupply pin grounding

All the cables / Optical fibre used for connectivity should be laid as per

the Site engineering practice/guide lines and along the right side of the

rack.

E1 connection through a 62 way D- type connector (on TET-28, TET-21,

TET-16 and metral connector onTET-63 card.

E1 cable should be directly connected to the DDF/IDF

The cable is available in 4 bundles of 8 pair is

Pair 1-8 White bundle

Pair 9-16 Yellow bundle

Pair 17-24 Brown bundle

Pair 25-32 Blue bundle


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E3 connection on TE31 card with BNC connector (RX-TX)

E4 Connection on A1E4 card (E4 interface through BNC) Ethernet connection from ETC card RJ45 connector (10/100 Mbps)

STM-1 Connection on A011/A012 cards by SC/SFP connector (Optical)

STM-1e TX- 1 Faculty

ALTTC, Ghaziabad

STM Connection on A012E or A1E4 card (BNC connector)

Diag connection through RJ45 connector at SCU-4 or ETC card

Installation of the chassis to the rack:-

Node View

The positions of cards in the rack Slot no. 6,7,8&9 all fix slots and The slot no. 1

to 5 and 10 to 15 are transaction slot

Slot No. Card

0 Back Plane

1&13 STM aggregate card

2,3,4 E1Tribute(TET16,21,28) with 62 D type connector 5 TE31/TE33 for VC3

With BNC connector

XCC-16 control card

(D9 connector for BITS)

8&9 SCU4 card system control unit with RJ45 diagnostic connector

16 Power supply 1&2(with three pin connector)

17 Fan tray


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18 MFC (Multi frame card)

Cabling:-

TP01: Ethernet Tributary card (10/100Mbps eight interface RJ45)

TP01FT: Fast Ethernet tributary card (for 10-base-T/100-base-T) and for

100-base-FX Ethernet ports

A01/A012: The aggregate cards having the fiber connectivity withSC/LC connector

Cables and optical fibers used for connectivity should be labelled

according to the site engineering practices

Fiber connector cleaning - lint-free, nonabrasive cleaning pad or lens

tissue

Insertion of the card

Identify the correct position of the chassis.

Identify the appropriate slot into which the card is to

be inserted

Slide in the card along the guide ways provided on the chassis with theejector levers in the horizontal position to engage the ejectors to the

chassis groove

Operate the two ejector levers (inwards) simultaneously to engage the

card to the backplane

Insertion of the fan tray:-

Identify the correct slot for the fan tray


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Slide the fan tray with carrier along the guide ways provided on the

chassis To engage the fan tray to the backplane connector, push the carrier

handle

Fasten the carrier plate to the chassis

Commissioning of SDH System:-

Default IP of NE is 192.168.1.254

Connect laptop to NE using cross cable

Change the laptop IP to the same subnet as node

Right click .My Network Places. click properties

Right click on .Local Area Connection. click properties

Double click TCP/IP Choose use following IP address and enter IP and click ok

Open the Internet Explorer with default IP of the node

Login with Username . tejas. and password . j72e#05t.

Enter the Ethernet IP and Router ID and submit

Node will soft reboot

Set Node Date and Time Nominating a synchronization reference clock source to a network

element

Provision optical and electrical ports

Enable OSPF

Enable Auto Discovery Configuration


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Configuration Management and Performance

ManagementNetwork Topologies:

Topology is the layout pattern of interconnections of the various elements(links, nodes, etc.) of a computer network. Network topologies may be physicalor logical. Physical topology means the physical design of a network includingthe devices, location and cable installation. Logical topology refers to how datais actually transferred in a network as opposed to its physical design.

STM-1 can work with any topology given below:

Point to point topology.

Star topology. Bus topology. Ring topology.

But point to point and ring topology is commonly used in STM networks. Fewof above topologies are explained below:

Point to Point Topology:

Figure4.1: Point to point topology


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Point to point topology is used between the two systems in which both areconnected to each other. It is used at the edge of network.

Ring Topology:

Ring topology is used at the core of the communication network. In present days we are using this

topology in our core networks. Figure 4.2 shows ring of three systems.

Figure4.2: Ring topology

Automatic Protection Switching (APS):

Modern society is virtually completely dependent on communicationstechnology. Trying to imagine a modern office without any connection totelephone or data networks is like trying to work out how a laundry can operatewithout water. Network failures, whether due to human error or faultytechnology, can be very expensive for users and network providers alike. As aresult, the subject of so-called fall-back mechanisms is currently one of the most


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talked about in the SDH world. A wide range of standardized mechanisms isincorporated into synchronous networks in order to compensate for failures innetwork elements.

Two basic types of protection architecture are distinguished in APS.One is the linear protection mechanism used for point-to-point connections. Theother basic form is the so-called ring protection mechanism which can take onmany different forms. Both mechanisms use spare circuits or components to

provide the back-up path. Switching is controlled by the overhead bytes K1 andK2.

Linear Protection:

The simplest form of back-up is the so-called 1 + 1 aps. Here, eachworking line is protected by one protection line. If a defect occurs, the

protection agent in the network elements at both ends switches the circuit over to the protection line. The switchover is triggered by a defect such as los.Switching at the far end is initiated by the return of an acknowledgment in the

backward channel. 1+1 architecture includes 100% redundancy, as there is a

spare line for each working line. Economic considerations have led to the preferential use of 1: n architecture, particularly for long-distance paths. In thiscase, several working lines are protected by a single back-up line. If switching isnecessary, the two ends of the affected path are switched over to the back-upline. The 1+1 and 1:n protection mechanisms are standardized in itu-trecommendation g.783. The reserve circuits can be used for lower-prioritytraffic, which is simply interrupted if the circuit is needed to replace a failedworking line .

Figure 4.3: Linear protection


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Ring Protection

A ring is the simplest and most cost-effective way of linking a number of network elements. Various protection mechanisms are available for this type of network architecture, only some of which have been standardized in itu-trecommendation g.841. A basic distinction must be made between ring

structures with unidirectional and bi-directional connections.

Unidirectional ringsFigure shows the basic principle of aps for unidirectional rings. Traffic is

transmitted simultaneously over both the working line and the protection line. If there is an interruption, the receiver switches to the protection line andimmediately takes up the connection.

Two fiber unidirectional path switched ring

Bi-directional ringsIn this network structure, connections between network elements are bi-directional. This is indicated in figure 8 by the absence of arrows whencompared with figure. The overall capacity of the network can be split up for


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several paths each with one bi-directional working line, while for unidirectionalrings, an entire virtual ring is required for each path.

Two fiber bi-directional line-switched ring (blsr)

Cross-Connection

Cross connection is important function of stm-1 equipment. By using thisfunction we can connect PCMs of one station to PCMs of another station. For example 1 st PCM of Patiala station can be connect to 7 th PCM of Rajpurastation.

To perform these function we must following.

Configuration--- ---Cross-Connection------add cross-connect---Selectnumber of connections---select capacity--- ---circuit identifier--- ---selectdirectionality--- ---source add.--- --- destination add.--- --- submit

Now connections are established.

We can also give the protection path, if working path has been failed.


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Go to Configuration--- ---Cross-Connection------add cross-connect---Selectnumber of connections---select capacity--- ---circuit identifier--- ---selectdirectionality--- ---source add.--- --- destination add.--- --- SNCP protection(enable)--- --- submit.

Each cross-connection is defined by its parameters:Output port : Connection Destination End (Slot name and port number of selected card)

Mode : Unidirectional or Bi-directional

Input port : Connection Origin End (Slot name and port number)

VC-n type : Either VC4, VC3 or VC12

Protection : Protection Connection Origin End (Slot name and port number), if SNC protection is used.

Status: Working or protection according to channel which is carrying traffic.

Various tests performed at Transmission Lab


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Transmission at one end and Reception at other end. Transmission and Reception at same end using Loop back. Transmission and Reception at same end using Loop back with protection .

Transmission at one end and Reception at other end

Transmission at One End and Reception at Other End

Here the problem statement is that I have to send my data using PCM 1 atsystem A (192.168.33.100) to the system B (192.168.32.100).

Solution : various step involved are given below:

1. First choose the configuration on welcome page of STM-1.

2. Click on cross connect.

3. Then click on Add cross-connect.

4. Select number of connections.

5. Select capacity, number of connections, and directionality.

6. Select source PCM like here we are using PCM 1 so here source is

E1-1-5-1. 5 is MUX card.

7. Then select destination which is OLT it may be 3 rd or may be 4 th.

here we have to send 1 st PCM of MUX card on OLTs 1 st PCM so


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destination is STM-1-4-1. And accordingly choose value of K L M

which is value of PCM card number. For 1st

PCM the value of K LM is 1 1 1.

8. Then enable SNCP destination protection for standby. And then use

OLT for standby here it if STM-1-3-1 and value of K L M is 1 1 1.

9. Then click on submit.

10. Then cross connect is added.

Then to check the connection connects 1st

PCM to digital transmitter analyzer.

Digital transmission analyzer observations

Test 1 Observation:

Test parameters Value Test parameters Value

EFS 300 ES 0

N-SES 300 SES 0

AS 300 US 0

N-DM 5 DM 0

AM 5 BRK 0

After fault:Test 1 Observation after fault

Test parameters Value Test parameters ValueEFS 0 ES 0N-SES 0 SES 0


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AS 0 US 300N-DM 0 DM 0AM 0 BRK 0

Transmission and Reception at same end using Loop Back

Transmission and reception at same end using loop back

Here the problem statement is that I have to send my data using PCM 1 atsystem A to the system B and resent back same data using loop to system A.

Solution : various step involved are given below:


2.

Click on cross connect.3. Then click on Add cross-connect.






Here we have to send 1 st PCM of MUX card on OLTs 1 st PCM so


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which is value of PCM card number. For 1st

PCM the value of K LM is 1 1 1.





11. Results: Data was received error free. When we disconnect anyoptical fiber data transmitted is lost during fiber disconnects.

Transmission and Reception at same End using Loop Back with Protection

Transmission and Reception at Same End Using Loop Back With Protection


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Here the problem statement is that I have to send my data using PCM 1 atsystem A (135.10.110.14) to the system B (135.10.110.12) and resent back samedata using loop to system A with protection.

Solution: various step involved are given below:


2. Click on cross connect.

3. Then click on Add cross-connect.






Here we have to send 1 st PCM of MUX card on OLTs 1 st PCM so


which is value of PCM card number. For 1 st PCM the value of K L

M is 1 1 1.





Then to check the connection connects 1 st PCM to digital transmitter analyzerstransmitter and reception PCM 1 is connected to receive end of digitaltransmitter analyzer and at the second end loop back the PCMs.

Digital transmission analyzer observationsTest 3 observations

Test parameters Value Test parameters Value

EFS 61 ES 0N-SES 61 SES 0AS 61 US 0


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N-DM 1 DM 0

After fault:Test 3 observations after fault

Test parameters Value Test parameters ValueEFS 62 ES 1N-SES 62 SES 1AS 62 US 0N-DM 1 DM 0AM 1 BRK 1

Fault condition

Connect the transmitter and receiver terminal in DDF of system B to create aloop.

Connect the receiver and transmitter of 1 at system A.

To give protection to particular PCM choose that PCM to configure here we provision to give protection.


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1 is transmitted through D1 under normal condition. During fault it is need tosend through opposite direction in ring i.e. through B OLT and during protectionreceiver will be D4 of system we need to configure that during fault systemshould take data from D4.

Results: Data was received error free. When we disconnect any optical fiber data transmitted is not lost during fiber disconnects because of protection. Datawill be only lost if disconnect both the fibers.


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Data circuit Provisioning

Provisioning:-

The circuit provisioning feature is used for provisioning interfaces and creating

circuits between two NEs.

The features that can be provisioned include:

MSP/ASP Groups

Cross Connects

Order wire

OSPF configuration

Environmental Alarms

STM Ports

AUG

AU

TU

E1/DS1/E3/DS3 ports

Ethernet ports

VC Group


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Adding Cross Connect:-

To add the cross connect

Click Cross Connect in the provisioning interface page. The View Cross

Connect page is displayed

Click Add Cross Connect Enter the appropriate values against the fields

Click Submit. Success message is displayed upon confirmation


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NE Information:-

Information about Name

Router ID, Ethernet IP, contact, location, etc.


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Cross Connection of Three Cities:

M is Multiplexer

Here we have to send signal of 2mbps from Patiala to Ambala via Rajpura.

IP address of:

Patiala is 192.168.31.100, Rajpura 192.168.32.100, Ambala 192.168.33.100.

To add cross connect first of all change IP of your computer to which STM-1system is connected through NMS cable.

Then open internet explorer with addresshttp://192.168.100.31:20080 (for Patiala).

Then a window is opened called as login window.Then Login with Username: bsnl
http://192.168.100.31:20080/http://192.168.100.31:20080/http://192.168.100.31:20080/


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And password: 12345678

NE information of PATIALA:

Information about Name, Router ID, Ethernet IP, contact, location, etc.

Adding cross-connect at Patiala:


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Click on configuration.

Then click on Cross Connect in the provisioning interface page. The View Cross Connect page is displayed. Click on Add Cross Connect. Enter the appropriate values against the fields. Click Submit. Success message is displayed upon confirmation. The signal is send from Patiala to Ambala.

Source-MUX 5th

Card PCM1Destination-OLT NO.13 (K=1, L=5, M=1)


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Source-MUX 5 th Card PCM2

Destination-OLT NO.29 (K=2, L=3, M=2)


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Destination-OLT 59 (K=3, L=6, M=2)


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Overview of Cross Connections at Patiala-


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NE information of Rajpura:

Adding cross-connect at Rajpura:

Click on configuration. Then click on Cross Connect in the provisioning interface page. The View Cross Connect page is displayed. Click on Add Cross Connect. Enter the appropriate values against the fields. Click Submit.

Success message is displayed upon confirmation.


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This route is standby route. And signal is by passed here i.e. signal is bypassed from OLTs and no role of MUX card.

Source-OLT NO.3 PCM1 (K=1, L=5, M=1)Destination-OLT NO.4 (K=1, L=5, M=1)


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Source-OLT NO.3 PCM1 (K=2, L=3, M=2)



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Source-OLT 3 PCM3 (K=3, L=3, M=1)

Destination-OLT 4 (K=3, L=3, M=1)


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Overview of transmission at Rajpura


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NE information of AMBALA:

Information about Name, Router ID, Ethernet IP, contact, location, etc.


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Adding cross-connect at Ambala:

Click on configuration. Then click on Cross Connect in the provisioning interface page. The View Cross Connect page is displayed. Click on Add Cross Connect. Enter the appropriate values against the fields. Click Submit. Success message is displayed upon confirmation. Signal is received at OLT number 4 which is coming from Patiala.


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Future Trends

In future huge data rates will require in transmission media, of course media asoptical fiber will not change but technology like SDH has to modify. a modifiedversion of the SDH as DWDM,RPR, MLLN technology which consist of theoptical multiplexing offer us huge data rates of the order of giga bits. In case of wireless technologies by changing modulation techniques can enhance the datarates and security. Upcoming technologies like 3G supports data rates in mega

bits which are pretty much better. In switching the entire circuit switchingnetwork are to be modified to packet switched networks and will be IP based. In

nutshell future technologies will be more efficient, precise and faster ascompression to present technologies.


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Bibliography

www.bsnl.co.inen.wikipedia.org

www.google.com/images

STM-1 Equipment PDFs

BSNL Class Notes and PPTs
http://www.bsnl.co.in/http://www.bsnl.co.in/

project report on transmission

Documents