pulse sep-oct 2008

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MagazIne

Pulsesep-oct 2008

The official BIMONTHLY magazine of ECEA

ECEA Vista...2 Techies Arena...6 Gizmos...8 Tutorials...9 Nitty-Gritty...10 Gaiety...11

EDITORIAL

Welcome back to another issue of Pulse,

the scintillating magazine of ECEA.

Before you take a ride into our

informative and thought provoking articles, we

would like to share a few words with you. Today,

we are living in a golden age of technology. WithMoores words as motto, the worlds scientists

and engineers are coming up with surprises, almost

everyday. Faster and faster processors, mountain

of memory in miniature devices, redefined mobility

with bluetooth, 3G, WiFi, WiMax and many more

futuristic technologies are the order of the day.

While Intels 45 nm Penryn processors (for the

uninformed, its the core2duo) and Seagates

Barracuda 1.5TB hard drives have took the world

by storm today, the future has a lot more to offer.

Come next year and you will find the Intel 32nm

Westmere architecture processors gearing up to

power tomorrows PCs, and the future hard disk

drives would be hungry for even more data.

Wireless and mobility are the catch words. In this

regard, Nokia, Apple and other biggies are doing

their duty religiously in the quest towards a

connected world. It seems technology is growing

at an exponential rate. And the interesting fact is

that all the excitement that is happening is our field,

electronics and communication! Ambient

intelligence, Smart antennas, Cognitive radio,

Power line communication, etc are some of the hot

topics of research today. Tomorrow, we will be part

of this great revolution and scale even more heights,spearheading mankinds progress. Wow! Isnt this

a great feeling? The future is in our hands! Hmmm,

now, coming to our stories, hats off to all the ECEA

members for a successful Resonance 08. And with

the semesters end nearing, assessments, lab exams

and end semester exams will be looming large in

everyones mind. Lets take them in the right spirit

and give them a shot. Pulse wishes everyone to do

their best and special wishes to all those who are

going to bell the CAT this November !

A short bio-sketch on

Gp.Capt..K.Balasubramanian

CORPORATE TALK

We had the golden opportunity to interact

with Gp.Capt.K.Balasubramanian,

IAF(Retd) Chairman, Teledata Informatics

Ltd which is a global software solutions company

providing enterprise-wide solutions for the

Education, Energy and Telecom sectors and has itssubsidiaries and operations managed from 48

countries & 166 locations.

He graduated in Mechanical Engineering from GCT, Coimbatore in 1962

He was then commissioned in the IAF technical branch and served the Air Force

for 32 years. He was awarded the postgraduate degree in Cranfield Institute of

Technology, UK in Aircraft design. He also holds an MBA degree in Finance. He

is a qualified interpreter in Russian language, having passed the qualifying

examination in distinction He had served as the deputy director of Light Comba

Aircraft Project at Aeronautical Development Agency. From 1994, he is servingas the Managing Director and Chairman of Teledata Informatics Ltd., a reputed

global software, telecommunication and networking company. He is a fellow and

member of several professional societies in India and abroad .He likes E-Mentoring

Sir, could you tell us about your company?

Teledata Informatics Ltd. was founded in the year 1990. We went public

in 2000 and currently have the faith of a million investors. We are the only public

listed company that produces thirty one different software products for global

markets . Our areas of expertise include software design and architecture

datacentre, VoIP, web solutions, e-learning (both content and delivery) and PC

manufacturing. We follow the concept of backward integration. For example, if

we are to develop a software product for a ship, we buy a ship for ourselvesThen we test and refine our product to meet all of the customers needs. Though

this takes a lot of investment in terms of capital, our products are exactly wha

the customers what. Our customers can see for themselves the testing and their

results. And our company meets the CMM level 5 standards, the highest in terms

of quality. (CMM level 5 standard,though process centric defines and directs (in

the form of a self correcting model) as an ideal standard - one defective produc

in 10 million!). As students, you would like the contributions of Teledata in the

field of Education like Web EIM a web based Educational Management system

marketed in USA and digital Education in 7 states in India and our products and

services for learning Management and Learning content Management System

Our E-Learning products cover the global audience in the field of Marine

Engineering and Banking .You please also see

ECEA

)

)))

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http://www.teledata-usa.com, http://teledatamarine.com and http:/

/tts-consulting.com and other subsidiaries etc

Youve worked in Air Force and Aircraft design. And now you

are heading a software and telcom company. How has your

experience in aeronautical field helped you?

The quality levels in aircraft industry are high for obvious

reasons and imbibing the quality levels in daily working life helps

in producing higher quality software and telecom products andservices. Also the software used in the aircraft systems demand

greater testing and reliability, which is also useful for general

software and telecom products . Teledata also has developed

software for airports and aeronautical systems

To be successful in telecom & networking industry, what skills do

you think is expected of budding engineers like us?

What the industry expects from you freshers are, the right

attitude and enthusiasm to learn new things. Given these two, other

skills can be taught and you will learn them quickly. Please remember

that companies hire for attitude and personal qualities and then

train for knowledge and skill. At the age of 21, boys and girls haveto be physically tough, mentally alert and emotionally stable. With

these three Core Strengths, under your belt, your ability to observe,

analyze, adapt and refine yourself to the expectations of the industry

will be very high .Knowledge, Skill, Attitudes, Values and team

spirit etc will eventually reach you and you will be able to rise to

your full potential If you want some specific answers from me, Id

like to add the following. Engineering Education is a fine balance

between theory and practice. During your four year engineering

course you would have studied more than 50 subjects. They form a

foundation, especially your math skill, which is of prime importance.

Then, you should have done some work wetting your hands , say

a project, on your own. That would be sufficient.

Do you think if there is a relevance between our curriculum in

college and the job?

I dont think the relevance factor is an important one,as

life cycles of products and services are only 5 years . As I said

before, the four year course gives you a foundation on which you

build your career. If you have the enthusiasm and attitude you

need not bother about the relevance. It is here that E-Learning will

assume greater role in retraining Engineers and technicians in newer

areas of knowledge and skill.

Does your company offers internships for students like us?

Yes, we do offer internships but not in a very large scale

as other companies do. But we have a lot of plans to change the

situation and offer more internship opportunities in the future, in

the form of finishing schools.

Sir, your message to the students?

Today there are numerous global opportunities.

Knowledge is the key factor that would decide your destiny. Acquire

enough knowledge and use it to acquire additional knowledge.

And now, it is not like my times. You have a good friend called

Google. Use it to expand your horizons. Automation and Embedded

systems are the hot fields in todays electronics industry. Theyre

powering aircrafts, ships, automobiles and many appliances today

and theyre sure to play an even greater role in the future. It is

expected that embedded systems can have about five times the

impact that software had over the last ten years.

ECEA VISTA....

Potential Unleashed by Logic Saturated Engineers

ALUMNUS COLUMN

the prestigious IIM B (Indian Institute of Management, Bangalore)

We had the opportunity to talk with him.

Here are a few excerpts from the conversation:

Life at IIM B

Arun finds the hectic time-packed life at IIM-Bangalore

enthralling. He says, Everyone here is busy doing something orthe other .Not even a single minute is wasted. We hardly sleep for

4 hours. He further adds, The live projects at IIM really prepare

you to face the corporate world. The students are trained to take up

the challenges of the real world. At the IIMs, a student has to be

constantly updated with his curriculum and last-minute preparation

for the exams would be impossible. One has to be very systematicfocused, self-disciplined and self-directing to succeed in the

institute.

Arun briefed us on how the students are tested at IIMs

He says, we have 3 semester exams every 6 months. Besides

surprise quizzes are conducted at any point of time. Of course the

remaining time is spent working on projects. When asked abou

case studies, he gave us his own experience at a General Hospital in

Bangalore. The hospital received regular supply of medicines bu

other hospitals in nearby towns and cities had to collect their medical

supplies from this hospital in Bangalore. This caused many problems

like delay of medicines. The students tried to rectify this problem

by providing solutions like opening branches in those cities and

having better ways of distribution. He says, the best part of projects

is that they are implemented before your eyes.

Arun also gave us a few tips on how to prepare for the

surprise quizzes conducted at IIMs. He says, Surprise Quizzes are

very challenging, they are not at all simple despite how much effor

one puts in. One should regularly follow professors. IIM is a place

where management gurus and pioneers across the world come. It

would be extremely useful to understand what concepts they explain

Most of them can be easily applied in these quizzes.

High achievers spot rich

opportunities swiftly, make big

decisions quickly and move into action

immediately, so said Robert H

Schuller.

Atrue illustration of this statement

is Arun A, an alumnus of our

DECE, CEG & the topper of his

batch, is currently pursuing his Post-

Graduate Programme in Management in

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....ECEA VISTA


Arun also gives us a glimpse about the curriculum at IIM.

He says, The syllabus at IIM is really demanding. Subjects like

Managerial Accountancy and Operational Management are

formidable as they are filled with complicated mathematical problems

and mind-boggling questions.

Future Plans and Job Prospects

Arun gave us a good guidance about the job prospects inmanagement field. He says, The hottest career options inmanagement are Finance and Corporate Strategy. But one should

follow his preference rather than going with the tide. Arun

enthusiastically replies when asked about his future plans, I just

did my internship in Rothschild, a leading investment bank. So I

would prefer to take up a job in Corporate Strategy or Finance for

now. Also, I do have plans of staring my own venture later.

Aruns tips for belling the CAT

Practise regularly all the sections. Start with the section

you are extremely comfortable with and then move to the

other sections.

Read newspapers like the Economic times and The Hindu.

Read a lot of periodicals and keep your vocabulary updated

always.

Reading Economic Times will help you tackle questions in

Data Interpretation and the Group Discussion

In the group discussion round, be confident in whatever

you speak. Even though you dont have any points, try

getting it from others.

Be cool and composed during the personal interview.

Know yourself in and out to answer any question aboutyourself. Always be prepared about a few general

questions.

INTERVIEW WITH THE PRESIDENT, SAAS

[email protected]

Watch out for the exhilarating forthcoming

Dec-Jan 2009 PULSE issue!

We welcome technical or general articles,

crosswords, puzzles, interesting facts,trivia, suggestions or any other constructive

contribution!

Kindly note we do not publish plagiarised

articles.

Mail us or hand over your artefacts (in soft

copy) to any PULSE member.

KudostoMr. Kalaiarasan P, the President of Students

Association and Arts Society (SAAS) for his well crafted

prospective plans and efforts. By calling a spade a spade

we would say SAAS has brought on tremendous and authentic

changes in our campus in the past and we may expect the best in

the future as well. Talking to the President, who also belongs to our

IV Year ECE department, this is what he had to say to the PULSEcrew

Can you tell us about SAAS?

Student Associationand Arts Society (SAAS) is the deep

inner desire and voice of CEG students. It is involvedin organizing

various inter-college and intra-college events such as the Freshers

party, Agni, Techofes, etc. It functions as the caretaker of all co-

curricular and extracurricular activities in the campus. SAAS was

inaugurated on29th September by the Honourable Chief Guests

Police Commissioner R Sekar and famous Music Director Ganga

Amaran.

How can we contact SAAS and voice our suggestions?

One can always contact their class representatives round

the clock. The SAAS office bearers can be got in touch in the

SAAS office between 4:30 and 5:30 PM. Also we are planning to

have proper means of communication between SAAS and fellow

college mates via notice boards exclusively for SAAS in canteen.

Where is the SAAS office?

It is located near Hall No.13 in the School of Mathematics

building.

For the uninitiated, can you elaborateabout your team

composition?

Elections would select sixteen 2ndyear students, sixteen

3rdyear students and fourteen 4thyear students. From the selected

representatives, we elect the office bearers of SAAS which include

the President, Vice-president, Lady Vice-President, Arts Secretary

all from 4thyear; while General Secretary & Assistant Arts Secretary

are from 3rdyear and the Joint Secretary is from 2ndYear.

Can you recollect some of the landmark changes by SAAS in our

college?

SAAS was responsible for the construction of ramps

exclusively for the differently abled in S&H block, ground fencing

opening of coffee shop and several other constructive alterations

What are your agenda and plans as the President of SAAS?

The various proposed plans are as follows:

Railway ticket booking counter inside college.

Wifi in all hostels

Providing high configuration Laptops at affordable rates

Creation of blood group bank

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ECEA VISTA....


For all those who aspire to do higher studies after their

graduation, here is a brief look at the various entrance

exams you may have to take to stand a chance in the forbidding

competition for the limited number of seats in the various prestigious

institutions.

ME / M Tech / MSGATE

Graduate Aptitude Test in Engineering (GATE)is an annua

exam for admission to M.Tech and M.S. programs in most

engineering institutes inIndiaas well as pharmacy institutes. It is

regarded as a benchmark test for engineering graduates in India.It

is conducted jointly by the Indian Institute of Science and the

seven Indian Institutes of Technology.

GRE

Graduate Record ExaminationorGREis astandardized

testthat is an admissions requirement for manygraduate

schoolsprincipally in theUnited States, but also in other Englishspeaking countries.

TOEFL

TheTest of English as a Foreign Language(TOEFL

evaluates the potential success of an individual to use and

understand Standard American Englishat a college level. It is

required for non-native applicants at many English-speaking

colleges and universities.

IELTS

IELTS stands for International English Language Testing

System. It is a test ofEnglish languageproficiency. IELTS is

accepted by most Australian, British, Canadian, Irish, New Zealandand South African academic institutions, by more than 1,800

academic institutions in the United States, and by various

professional organizations. It is also a requirement for immigration

to Australia and Canada.

COMPETITIVE EXAMS FOR HIGHER STUDIES

ECEA CORNER

The ECEA was inaugurated on 2nd September 2008 by the

Honourable Chief Guest Mr. D Varadarajan, Principal General

Manager, BSNL, Tamil Nadu Circle. The highlight of the event

was the launch of PULSE and the formal kick off of the ECEA

website.

So, whats happening in ECEA? Lets have a quick briefing:

1) IEEE Chapter:

In order to provide ECE students a global exposure

(including papers, projects, seminars, etc ) in the field of Electronics

and other relevant fields, an IEEE branch is to begin in our

department very soon. (25$ membership per year ). For the ECEians

dreaming of doing an MS or an MTech, this membership will give

you an edge.

2) ECEA Teams:

Networking is todays mantra.One should know his seniors

and the industry people in his area of interest. Experience is

precious. This will be a kind of a mentorship programme which will

last even after college. This network (MBA, MS, Work-related) willenable you know how to prepare yourself for your career.

3) Events:

ECEA has a number of teams like Events, Logistics,

Marketing, Corporate Relationship or Design;if you want to join

any of the above team, do contact the ECEA office bearers directly

or through your Organising secretaries or Joint Secretaries.

Also, as always the enthusiastic PULSE team is there to

cover every nook and cranny of DECE and keep you informed.

Famous quotes

The heights by great men reached and kept,

Were not attained by sudden flight,But they, while their companions slept,

Were toiling upward in the night.- Henry Wadsworth Longfellow

What you get by reaching your destination isnot nearly as important as what you will

become by reaching your destination.- Zig Ziglar

Most folks are about as happy asthey make up their minds to be.

- Abraham Lincoln

Insurance for differently abled students.

Drinking water supply in coolers throughout the college.

Renovation of gym.

Xerox machine instalment at easily accessible places.

Links fromannauniv.edu updated regularly-enhancing cultural

activities exposure, giving a clear insight to all activities.

What are the cultural events organised by SAAS ?

The events under the supervision of SAAS are as follows:

Agni the intra-college cultural festival

Techofes the inter-college cultural festival

Any message to the students of our college?

SAAS strives to do its best in catering the needs of the

students in every possible way. We kindly request the full

cooperation of all our mates in implementing our agenda for this

academic year. Together, lets bring out the highest quality in all

endeavours.

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distinguish yourself from others. It is a common myth that only

CGPA or projects matter. They do, as a matter of fact, but the rea

focus is on your attitude.

What does Bell Labs deal with?

Bell Labs is not a new name in our domain. It deals with a

variety of fields intricately connected with our department. However

Bell Labs India has only Networking and Network Managemen

section.

Can you categorize the work as hardware or software oriented?

Networking is a tricky field that cannot be categorized as

such. But I think the lean is on software.

What are the positives you can pick up from Bell Labs?

Again, there is this popular myth that an internship in Bel

Labs is like having the blue moon. You do nothing more significan

than at other places. The main difference is that you get a taste of

actual industry competition and the way to adapt yourself to such

scenarios. You get to face situations where you only know what todo and not how to do it. You get an opportunity to work with the

big shots in business.

When should we apply to Bell Labs?

Now is the right time. I have already conducted a smal

session for our immediate juniors on how to apply. You will know

the results somewhere before your sixth semester

Any words for the juniors?

Internships are a great way to learn. There are cool offers

and it can be fun too. You will get to know yourself better if thechoice of your internship is a company that deals with challenging

projects.

CHAT WITH A BELL LABS INTERN

....ECEA VISTA


MBA

GMAT

TheGraduate Management Admission Test(GMAT) is a

computer adaptivestandardized testfor measuring aptitude to

succeed academically in graduate business studies.Business

schoolsabroad commonly use the test as one of many selection

criteria for admission into anMBAprogram.

CATTheCommon Admission Test(CAT) is an all-Indiatest

conducted by theIndian Institutes of Management (IIMs)as

anentrance examfor the management programmes of its seven

business schools. CAT scores are also accepted by approximately

120 MBA institutes in India.. More than 2,30,000 students compete

for about 1500 seats in the IIMs. This is said to make the IIMs more

selective than theIvy LeagueUniversities.

XAT

XLRI conducts Xavier Admission Test (XAT) on All India

level to select the most appropriate students for management

education in XLRI and 60 other Management Institutes.

MAT

Management Aptitude Test (MAT) is a National Entrance

Test conducted by Centre for Management Services (CMS), the

specialized division of AIMA. MAT exam is used as a benchmark

by hundreds of AICTE approved Institutions & University

departments to screen candidates for admissions to MBA

programmes.

Here are a few excerpts from our chat with Ranganathan

Ramaswamy, IV Year

What do internships mean to us?

Internships are programmes that allow students to interact

with actual industry or research environments aiding them to gain

valuable experience.

Is there any distinction between various programmes?

Internships are basically of two types. Its not any religious

way of demarking boundaries between types. In general, some

programmes deal with research and while others deal with actual

field work and implementations. You can group them that way.

Under what category does Bell Labs offer internships?

Bell Labs offer internships under both categories. There

are research avenues as well as ventures and development kind.

Who can get an internship at Bell Labs?

There are no hard and fast rules. You need to give the

impression that you are willing to learn. You must be able to

Triv

iaCorner

1. Spiders have transparent blood.

2. Penguins can convert salt water into fresh

water.

3. Black whales are born white.

4. A woodpecker can peck twenty times a

second

5. The state of florida is bigger than England.

6. Snake venom has 90% protein.

7. Storage capacity of human brain is greater

than 4 tera bytes.

8. Rhythm is the longest English word without

vowels.

9. Mozambique is the only country to have all

the vowels in its name.

10. United Arab Emirates is the only country to

have alternating vowels and consonants in its

name.

11. The word GIRL appears only once in Bible.

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Harish guruprasad, Iv YEAR

techies arena......

Hello people, the objective of this series of articles is to give

everyone an idea about the topic and make interested

people refer for stuff. If you are confused or not clear about

some concept here, be heartened in knowing that confusion is the

first step to proper appreciation of any subject. It is more true in thehazy subject of neural networks than any other subject. Now onto

the journey.

Advances in computer technology has led to the building

of computers capable of doing calculations which would take

humans hundreds of years to compute in seconds. But we are still

far from building a computer which can understand and learn a

natural language like english or tamil, something a human is able to

do quite easily. This has led to many hypotheses which say that,

the reason for this is the different architecture of the nervous

system. The number of neurons range from 10 to 100 billion. Though

a large number, it is quite possible to build a supercomputer which

uses 10 billion transistors. The main difference then is not the

numbers but rather the nature of the connection and the way in

which knowledge is stored. Moreover it is the fault tolerant nature

of the brain which has led people away from the typical computer

model. The brain would function almost normally even if a large

number of neurons fail to function, But a computer could collapse

catastrophically even if just one transistor goes awry. There have

been quite a few mathematical models for the neuron, but none has

even neared explaining the functionalities of the brain. So much

about the brains functioning is unknown. Ask any question about

the functioning of the brain to a specialist and the most probable

answer would be I dont know. So the models for the brain are

based more on heuristics and guesswork than mathematical rigor.

The first model of the neuron was proposed by

Mccullough and Pitts. It was quite simple. It had a number of inputs

,each of them weighted by a specific number and they were added

and fed to a non linear function like a thresholder. Many refinements

followed. Though it was proposed just as a model for the neuron, it

began to be looked upon with interest even when it was proved the

neuron was far more complicated than that. It was mainly because

people began to build networks out of such structures and they

began to be used in pattern recognition and classification

applications on their own merit and not because it modelled the

brain . Different architectures of the so called neural networks also

began to develop. Some of the noteworthy architectures were lFeed forward Artificial Neural Networks (e.g) multilayer perceptron

State Transfer networks-- (e.g) Hopfield network

Competitive learning (e.g) Self organising maps.

The Hornik-Stinchcombe-White theorem greatly increased the

popularity of FANNs as it stated that any non linear function can

be approximated by a ANN of appropriate size.

Though these models were created to simulate the brain,

PATTERN RECOGNITION AND NEURALNETWORKS SOME BASICS

they will most probably never near the functionality of the human

brain. I have restated this because of the misconception that ANNs

are intelligent and sentient beings which can think for themselves

ANNs are mostly used only in pattern recognition. Pattern

recognition is the science of recognizing patterns in any data, it

may be the recognition of a handwriting pattern, a pattern describing

the face of a particular person etc. Most problems can be rephrased

into pattern recognition problems. The data from which any pattern

is to be recognized is given as a N element vector. For example to

recognize faces on 24*24 images, the data could be 576 elementvector.

In most pattern recognition problems there are two phases

training and operational. For the solution to detect patterns rightly

in the operational phase, it must be instructed as to what the pattern

is in the training phase. This is usually done using positive and

negative exemplars. For example in a handwriting recognition

problem the system is given samples of the persons handwriting

to recognize (positive exemplars) and samples of some other people

writings (negative exemplars).

Most pattern recognition problems are phrased as

separating points in a N dimensional space with N-1 dimensionasurfaces. (N can range from 2 to tens of millions). Consider for a

N=2 case. In the training phase let there be 10 exemplars ( 5 +ve and

5 ve ). The two dimensional data may be plotted on a graph.

So if the line separating the positive and negative

exemplars is found during the training phase, in the operationa

phase we could find out which side of the line the new data lies in

and we can classify it as being closest to positive or negative

based on that. This is just what a neural network or any othe

pattern recognition system does, find a line (an N-1 dimensiona

line). This line is called the decision boundary. Finding a linear

boundary is quite easy, but most real world data cant be separated

by linear surfaces. Finding 100 dimensional complex surfaces

separating 101 dimensional data isnt something you can do by

yourselves between bath and breakfast. Finding nonlinear surfaces

is what the Hornik theorem is about, neural networks can find any

non linear separating boundary (if it exists) given sufficient neura

nodes. This is the reason for popularity of ANNs. But there are 2

important riders associated with this 1) given sufficient neura

nodes 2) if a boundary exists . Sometimes the number of neurodes

may reach several million, which would make it a wee bit difficult to

implement the neural network on the TRANSLTR ( remember digita

fortress?). Sometimes the boundaries dont exist , meaning that

though positive and negative training images can be separated the

data cant be. For example you could have a complete database of

many faces for detecting a face anywhere in an image, but in the

operational face there may come a face part of which is under


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shadow causing drastic variations in pixel values , so the image

could come on the other side of the line.

Problem number one cant be avoided, but it can be

diminished by using lesser dimensional independent data than high

dimensional correlated data, using alternate architectures for

specialized problems, more processing power. Problem number 2 is

much more serious though. To counter problem 2, instead of giving

direct data like pixels as vectors, some function of the data that is

invariant to changes like illumination , rotation and translation canbe used. For example each pixel may be normalized in magnitude

within a region to come across the illumination variance problems.

Such functions are called features, and designing the best features

for a particular problem is known as Feature Engineering. It also

enables to reduce the dimensionality of data. An example will be

given in the next issue.

WSNs merge a wide range of information technology that

spans hardware, systems software, networking, and

programming methodologies.

Fig:Sensor node architecture.

Microprocessors, power, and storage

A sensor network nodes hardware consists of a

microprocessor, data storage, sensors, analog-todigital converters

(ADCs), a data transceiver, controllers that tie the pieces together,

and an energy source. Recently, a new operating point has emerged

that suits all these components. As semiconductor circuits become

smaller, they consume less power for a given clock frequency and

fit in a smaller area. In simple microcontrollers, miniaturization

increases efficiency rather than adding functionality, allowing them

to operate near one milliwatt while running at about 10 MHz. Most

of the circuits can be powered off, so the standby power can be

about one microwatt. If such a device is active 1 percent of the time,

its average power consumption is just a few microwatts.

This scale of power can be obtained in many ways. Solar

cells generate about 10 milliwatts per square centimeter outdoors

and 10 to 100 microwatts per square centimeter indoors. Mechanica

sources of energy, such as the vibration of windows and air

conditioning ducts, can generate about 100 microwatts.

A typical cubic-centimeter battery stores about 1,000

milliamp-hours, so centimeter-scale devices can run almos

indefinitely in many environments. However, low-power

microprocessors have limited storage, typically less than 10 Kbytes

of RAM for data and less than 100 Kbytes of ROM for program

storageor about 10,000 times less storage capacity than a PChas. This limited amount of memory consumes most of the chip

area and much of the power budget. Designers typically incorporate

larger amounts of flash storage, perhaps a megabyte, on a separate

chip.

Microsensors

Sensors give these nodes their eyes and ears. Many

materials change their electrical characteristics when subjected to

varying environmental conditions. Sensors are manufactured so

these changes are predictable over a certain range. For example, a

thermistor is a variable resistor that changes smoothly with

temperature. An ADC converts the voltage drop into a binary number

that a microcontroller can store or process. Photocells and fogdetectors work similarly, but they consist of finely interleaved combs

separated by a material that uses incident photons or moisture to

change resistance. Many more sophisticated structures have been

developed to detect other phenomena. These structures consume

a few milliwatts and only need to be turned on a fraction of the time

Extremely efficient. ADCs have been developed so that the sensor

subsystem has an energy profile similar to the processor.

Microelectromechanical systems (MEMS) can sense a wide

variety of physical phenomena cheaply and efficiently. Researchers

can use the processes for etching transistors on silicon to carve

out tiny mechanical structures, such as a microscopic springboard

within an open cavity. Gravitational forces or acceleration can

deflect this cantilevered mass, causing powerful internal forces

that cause changes in material properties or delicate alignments,

which can be amplified and digitized. Manufacturers used the firs

major commercial MEMS sensor, the accelerometer, to trigger

automotive airbag release.

Whereas high-precision piezoelectric accelerometers cos

hundreds of dollars, MEMS provided sufficient precision for a few

dollars. Once the devices entered mass production, they could ride

the CMOS technology growth of modern chips to become

increasingly accurate while remaining inexpensive. A wide variety

of MEMS devices can sense various forces, chemicaconcentrations, and environmental factors.

Microradios*

For some time now, manufacturers have added sensors to

many appliances, vehicles, and gadgets. The breakthrough comes

from communicating sensor readings to other devices, translating

the physical world into informationbitsthat the devices can

transport, store, and process. Radio components can now be

manufactured using conventional CMOS technology, enabling

wireless entry devices, pagers, walkie-talkies, cell phones, and

wireless local area networks for mobile laptops. However, the amoun

of energy required to communicate wirelessly increases rapidly

WSN PART 2 - EMBEDDED NETWORK

TECHNOLOGY

ARUN S, IV YEAR

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with distance. Obstructionssuch as people or walls and

interference further attenuate the signal. Wireless LANs and cell

phones consume hundreds of milliwatts and rely on a powerful

infrastructure.

WSN radios consume about 20 milliwatts, and their range

typically is measured in tens of meters. For small devices to cover

long distances, the network must route the information hop by hop

through nodes, much as routers move information across the

Internet. Even so, communication remains one of the most energy-

consuming operations, with each bit costing as much energy as

about 1,000 instructions. Thus, WSNs process data within the

network wherever possible.

(* Now, even picoradios have been proposed a lot research work

going on under J.M.Rabaey)

SYSTEMS CHALLENGE

Bridging the gap between the hardware technologys raw

potential and the broad range of applications presents a systems

challenge. The network must allocate limited hardware to multiple

concurrent activities, such as sampling sensors, processing, and

streaming data. The potential interconnections between devices

must be discovered and information routed effectively from where

it is produced to where it is used. There must also be a means of

programming the ensemble.

TinyOS

Conventional operating systems such as Unix run well on

a 32-bit microprocessor at 50 to 100 MHz, with several megabytes

of RAM and a gigabyte or more of secondary storage. Today, this

can be achieved in a handheld device that runs for several hours on

a single charge. A more typical operating point for WSNs is one

year on a pair of AA batteries with a small fraction of these resources.

Further, this application focuses on structured interaction with the

physical world, rather than on complex human interactivity. The

developers of the open source TinyOS tailored it for this application.

CONSERVING POWER AND BANDWIDTH

Communication, usually the most energy-intensive

operation a node performs, must contend for a share of limited

bandwidth. The network stack attempts to minimize energy usage,

either by eliminating communication or by turning off the radio

when no communication needs to occur. Several approaches are

possible. For example, nodes could process data locally and only

communicate when they detect an interesting event. This approach

would be employed in an intelligent alarm system or an

environmental monitoring system that focuses data collection on

time or areas of interest. In many cases, crude low-power sensors

trigger higher-powered sensor devices, such as cameras.

Performing aggregation within the network can reduce

communication. For example, an application might need to determine

the average temperature at shaded nodes in a certain geographic

region. Selecting the subset of readings of interest could be

performed at the trees leaves, routing their aggregation as data

upward, so that each node transmits at most a single packet to

provide a statistical summary of its subtree. More sophisticated

aggregation could involve detecting distributed regions of interest.

Compression and scheduling also can conserve energy at lower

layers. Some protocol overhead is associated with data

communication to maintain routing structures, manage contention,

and enhance reliability. Sensor networks can avoid explicit protoco

messages by piggybacking control information on data messages

and by overhearing packets destined for other nodes. They can

use prescheduled time to reduce contention and the time the radio

remains live. This can be coordinated with the high-level application

behavior by, for example, periodic low-rate data sampling

Alternatively, the network could implement energy conservation

generically within lower layers by, for example, time division multiple

access.

In the spatial dimension, the network can assign specific

responsibilities to certain nodes, such as retransmission or

aggregation. Finally, the network can reject uninteresting packets

by turning off the radio after receiving only a portion. However

because these many optimizations can be mutually conflicting, a

rich and growing body of literature employs different combinations

of techniques under different application and platform assumptions

The Nokia E71 is said to be one of thebest phones Nokia has made to dateIts a device that a lot of businessmen

have been waiting for ... Now for thespecifications: Its got QVGA display (320x240pixels, 16M colours), the screen can bedisplayed as Detailed and Clean. Its a quadband phone that offers 3G connectivity in theform of HSDPA, as well as Wi-Fi. Its got110MB of internal storage that uses a SymbianOperating System 9.2 (series60 3rd editionFeature Pack1) powered by a ARM11 369Mhzprocessor and a micro SD slot that can offe

NOKIA E71 : REVIEW

anish a, iv year

support up to 8GB cards. The main highlight of this phone is thaits got a QWERTY keypad so its make it easy to type SMSs and

emails etc. Its got a 3.2megapixel with optional auto-focus and LEDflash and a secondary camera in the front for video conferencecalls. Its also got a built-in GPS receiver.

Now for the review, one can bang out SMS/emails on thisdevice, but theres a lot more under the hood and the E71 looks tobe a fairly good all rounder. The S60 implementation used is still alittle under-powered at times, most notably when opening imagesand playing back videos, but its fine for everyday productivity andgeneral mobile computing, the E71 now plays DRMed WMA music

The D-padis outstanding, the best such control Ive usedin several years. With the screen being QVGA, there are manymany compatible games (maybe N-Gage will make an appearancehere?) and having a good D-pad to work them is half the battleQVGA on the E71 looks crisp and good. Its only really when web

browsing that youll come a cropper - as usual with S60 Web insuch a low resolution display. Around the sides of the E71 are: Toppower button and mono speaker (good volume and quality). LeftmicroSD slot, microUSB port Bottom: charging port. Right: Volumeup/down, voice recording button, standard 2.5mm 4-way stereoheadset jack.

Most of the E71s rear is metal, with a patterned mirrorfinish, with the camera module adding a couple of mm to the 11mmbasic thickness in a little bump, featuring a tiny camera, a LED flashand an aiming mirror - though, to be honest, the entire back forms agood enough mirror for framing yourself when talking to cameraButtons either side of the case pop off the rear cover, revealing thehuge BP-4L battery, the same one as used in the E61i and E90(commonly known as the communicator) and 1500mAh will power

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the E71 for an eternity. Even with heavy Wi-Fi use and music/camera activity, the E71 will easily last a working day - and oftentwo. Take the battery out and you appreciate just how stunninglylight the E71s body is and how hard Nokia has worked to miniaturizeeverything. We can appreciate Nokia for the good design and workthey have done on this phone. The phone costs around Rs.20200.

Life would be better if we dont miss aphone call under any circumstance. But

what do we do if the mobile is in silent

mode and buried deep inside your bag or if

the surrounding environment is so noisy that

you are unable to hear or see the phone ring

or feel its vibration? Though the bluetooth

BLUETOOTH WRISTBAND

taking place to incorporate additional functionalities like displaying

time and the name of the caller .These functionalities demand

effective coupling with the operating system of the phone and

utilization of effective tactile communication devices. So, in future

we can imagine of a deaf person wearing a wristband which alerts

upon a wide range of activation signals from different sources like

doorbell, microwave oven, washing machine or whichever demands

his/her attention. Rather than having the transmission device

incorporated internally into the existing bluetooth functionality of

the phone, it can be added as a retrofit element to the phoneswithout bluetooth capabilities. The transmission device consists

of an array of MEMS actuators, a few piezo benders, mechanica

actuators, pneumatic actuators, direct pneumatics and solenoids

Trade off between power and range limits its range to 15 feet with a

battery life of 100 hours in standby. Apart from bluetooth, other

radio frequencies like VLF , VHF , ultrasonic and inaudible sound

can also be employed for communication between the

phone(transmission device) and the wristband(receiver device) .I

is apt to conclude that, this product is just a precursor of versatile

yet simple bluetooth gadgets to come in future.

headsets are already available in market to ward off these problems,

people with aesthetic sense dont prefer wearing it all the time. Let

us see some of the basics of bluetooth technology which is used in

this product. BT (BlueTooth) devices operate at 2.4 GHz in the

globally available, license-free ISM band. This band is reserved for

general use by Industrial, Scientific, and Medical(ISM) applications,

which obey a basic set of power and spectral emission and

interference specifications. So Bluetooth has to very robust, as

there are many users sharing this spectrum. The two devices

connected communicating via BT , retune their radio to different

frequency, effectively hopping from radio channel to radio channel.

In this way, BT devices use the whole of the available ISM band

and if the transmission is compromised by interference on one

channel, the retransmission will always be on a different, most

probably clear channel. The operating band is divided into 1 MHz-

spaced channels, each signaling data at 1 Mega symbol per second

so as to obtain the maximum available channel bandwidth. Using

Gaussian Frequency Shift Keying , a binary 1 gives rise to a positive

frequency deviation from the nominal carrier frequency, while abinary 0 gives rise to a negative frequency deviation. Each BT time

slot lasts for 625 microseconds, and, generally, devices hop once

per packet, which will be every slot, every 3 slots, or every 5 slots.

Three different power classes are defined, which provide operation

ranges of approximately 10 m, 20m, and 100 m. Two trendy bluetooth

wristbands named blualert and bluQ offer a solution to this problem.

Blualert uses v1.2 standard which is compatible with 1.1,1.2 and 2.

These wristbands vibrate to alert you whenever you get a call .

They can sometimes be used to alert upon receiving messages too.

BluQ has two buttons, one is the on/off button and the other one is

the transfer button which is used to transfer the control back to the

phone once the call has been sensed.

Simplicity in its usage along with the option to personalize

its appearance by using own pictures or the available wearable

skins makes it more appealing to youngsters who are concerned

about the cool factor. Bluealert can also be configured to act as a

security device to prevent you from losing your phone . If the

device finds itself more than five metres away from the phone after

being paired up with it, it buzzes. As far as aesthetics are concerned,

Blue alert looks more like a fashionable hi-fi bracelet . If you see

from a different perspective, it might be more useful than what it

sounds - deaf people can be alerted whenever they get a message

or alarm, so they will find $50 is worth paying. Further research is

sindhu a, iii year

Have you ever experienced this ordeal? You draw a nea

circuit diagram, hesitantly transfer it to a breadboard hoping

for the best and find that your shabby circuit works

perfectly. Next, with renewed confidence, you set about transferring

it to a general purpose PCB expecting the same results but wha

turns out is utter mayhem. Your PCB is laced with blobs of solder

covering one another without intent and the number of component

comes a distant second to the number of jumpers.

Dont despair. There is a way out of this predicament. Youcan build your own custom PCB in a jiffy and that too a neat one

like those computer motherboards with perfectly parallel copper

tracks running in harmony. For that you may have to get your

hands on the following materials-

1 Copper clad boards which are fiberglass boards with a thin copper

coating available in electronic goods shops.

2 Marker pen or Carbon paper (Any one will do).

3 Acetone (Found in nail polish remover).

4 Ferric chloride hexahydrate (FeCl3.6H

20) which can be purchased

in any shop dealing with chemicals.(Anhydrous FeCl3

can also be

used but it generates a lot of heat when dissolved in water and

needs HCl to start the etching reaction)

5 A plastic container.

6 Hand drill.

And most importantly you will require a Schematic and

PCB layout generating software. The best one around is EAGLE by

Cadsoft. A limited capabilities version is available for free from the

companys website. This software lets you draw your circuits

schematic in a schematic editor and generates a PCB layou

automatically. Once the layout has been generated you can take a

printout of it and use it to build your PCBs. Remember to take a

mirror image of the layout since the tracks will be printed on the

MAKING PCBS AT HOME FOR

DUMMIES

ARUN GOUD, IV YEAR

.....tutorials


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10/1210 Potential Unleashed by Logic Saturated Engineers

Nitty-Gritty....

bottom side of the PCB while the components will be placed on the

upper side. Once you are equipped with the layout you can start

following the steps given below.

Steps to come up with your very own home made PCB-

1 Wash the copper clad board using soap water and then wipe it

clean. Rub the surface with sandpaper to remove the deposited

oxides. The copper surface should be lustrous at this stage.

2 Draw the PCB layout on the copper surface using a marker

pen(preferably black colour). Alternatively a carbon paper can beplaced on the copper layer and the layouts imprint can be created.

3 Take a plastic container and fill it with warm water. Add a

tablespoon of FeCl3. Care must be taken as FeCl

3is highly corrosive

and can leave indelible marks on the floor and on your clothes if

spilled. For the same reason, dont use a metallic container.

Remember to use gloves and spectacles.

4 Place the copper clad board in the FeCl3

solution and stir slowly.

It takes around 15-20 minutes for the exposed copper to dissolve. If

the reaction is slow add more FeCl3.During this process the portion

of copper which is covered by carbon (from marker/carbon paper)

will stay untouched.

5 Remove the board and leave it to dry for some time.

6 Once dried, use a piece of cotton dipped in acetone solution (fromnail polish remover) to remove the carbon. Now the copper tracks

will be visible.

7 Test the board using a continuity tester for any short circuits.

8 Drill holes for placing the components.

9 Solder the components. You cant run away from this task.

However it will look simpler now since the layout generating

software creates an optimal layout with shortest interconnect length

and minimum number of jumpers.

In a world where money is more coveted than glory,

complacency is on the rise-A situation where people get

satisfied by a place in the podium, when they could have ended

up on its top!! The value which people attach to expectations and

promises, has decreased a lot. And we budding engineers are no

different?!?

We see so many students getting admitted in this institution,

carrying with them the expectations of so many people with them,

but miserably fail to make any great impact in the society today.

This is mainly because we get complacent once we get into this

institution, and the very fact of enjoying freedom of thought, action

and the power of independent decision making infuses us with awrong perspective about the freedom vested upon us and we get

caught in an illusion, and are reluctant to come out of the illusion

which gave us a feel of pseudo-success. By the time we realize this

(everyone will certainly!!!), we think its too late. This is nothing

but theFEAR OF ACCEPTANCE AND DENIAL(FAD). We fear

to accept because; we fear that we might get denied for mere

acceptance. The truth is that we get denied only because we fear to

accept.

The number of cases where our college students join courses

for competitive exams like CAT,JMET,GMAT etc. paying huge

money to coaching institutes but fail to attend even regular classes

READ ME

,is on the rise. This is only because of the fact that, we refuse to

think on the right accord before making decisions. We join these

courses, just because our neighbor or roommate, class mate has

enrolled in it. We join because we do not want unwanted scrutiny

from our parents on what we do in our leisure time. We do so

because we think we are providing us with an opportunity. An

opportunity which will pull us out of the FAD factor. We fail to

realize the real opportunity** in that opportunity. We use the

opportunity for our purpose. We fail to realize its real purpose.

**realizing the MBA dream

By we I do not mean all. The Day has already

dawned. The only thing is that, we late risers are still inside our

shell. All we have to do is to come out of the shell and feel the

sunshine.

P.S. Never mind the title. If youre reading this line, it has served

its purpose.

K. Ramasubramanian, IV YEAR

Here is one issue that has sparked of debates all over the

country. The question that lingers on everybodys mindis, Is the nuclear deal good or bad for India? People have

judged this issue, not based on facts, but on personal interests

business motives and imaginations. It has got a dubious distinction

of being called not clear deal because of the political and the

technical complexities involved in it. As this deal is going to be

active for a period of 40 long years, it is imperative that you and I

know it better than our 60+ politicians. Here we go!!!

It all began when Dr. Manmohan Singh went on his firs

trip to the United States on March 2005, after being crowned Indias

fourteenth prime minister in 2004. It was first time that a pact on

civilian nuclear energy cooperation was signed. Why it was thefirst time, requires a bit of rewinding

Jawaharlal Nehru, independent Indias first prime minister

proclaimed that we should not miss the nuclear bus as India had

lost out on industrial revolution, because we did not develop steam

energy. Many countries including US, UK, Canada and Russia

helped to build our nascent nuclear energy program. US, in particular

not only helped in nuclear power, but also to develop nuclear

weapons, because Washington did not want China to gain nuclear

dominance in the South Asian region. The face of all this

cooperation changed when Indira Gandhi decided to test plutonium

based nuclear weapon, at Pokhran, in 1974. The bomb was buil

using the used fuel imported from Canada .For the first time, theworld realized the scourge of nuclear proliferation. The internationa

community imposed restrictions on supply of nuclear fuel and

technology to India. Infact, the nuclear suppliers group or the NSG

was itself created in Pokhrans aftermath (India can take credit for

that!!!).

What followed was an era of nuclear apartheid, which

continues even till today.

Consequently, our nuke scientists were isolated from their

counterparts in western countries, leading to a technological

embargo. Our scientists started working from the scratch and

developed indigenous nuclear technology. India was lucky to have

NUCLEAR DEAL

SANTHAPRAKASH S, III YEAR

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....gaiety

TECH - QUIZ CORNER

visionary leaders like Dr. Homi Bhabha who envisioned a three

stage nuclear program. The first stage involves construction of

Natural Uranium, Heavy Water Moderated and Cooled Pressurized

Heavy Water Reactors (PHWRs). Spent fuel from these reactors is

reprocessed to obtain Plutonium. Stage two envisages construction

of Fast Breeder Reactors (FBRs) fuelled by Plutonium produced in

stage-I. These reactors would also breed U-233 from Thorium.

Finally, stage-3 would involve power reactors using U-233 / Thorium

as fuel. Thus the thorium based reactors would be the final

destination in Indian nuclear program as India is home to one-thirdof worlds thorium reserves.

We come back to July 2005, when President Bush on his

reciprocal visit to India, signaled the beginning of negotiating an

operational agreement called the 123 agreement. This was because

section 123 of the US atomic energy act, deals with nuclear

cooperation with other countries. US had already entered into 123

agreements with 25 nations. Meanwhile, the US senate passed the

H.R.Hyde act which was the legal framework on which the nuclear

deal with India had to be worked upon. This act contained many

extraneous provisions, which caused furore in India. They are:

Union Carbide had done to Bhopal and Enron had done to

Maharashtra. We would filling their cash chest for which we

would get in return

India will be able to feed her uranium starved nuclear reactors

which are running at half of the installed capacity. But many

nuclear experts have suggested that it was only a temporary

bug and could be solved by shoring up our domestic reserves

India will become a strategic outpost (not an ALLY) of the US

helping it to get strong foothold in the South Asian region.

Nothing else!!!

M.GOVIND RAMANUJAM, iv year

India should contain, isolate and dissuade Iran (a traditional

ally of India) from continuing with its nuclear weapon programand should sanction against Iran. This was a direct

interference in our sovereignty.

India had to cut down its plutonium based nuclear weapon

production and in the long term has to be a partner to the

Non-proliferation treaty. Again this was interference in our

strategic issues.

India was forced to follow a unilateral moratorium on nuclear

testing. Any nuclear test would end the nuclear deal. This

was a nefarious design to curtail our right to self-defense

from our enemies.

On the technological front too, India suffered a body blow

when it was learnt the existing embargo would not be lifted.

India had to develop its own reprocessing facility (which is

an important part of nuclear fuel cycle) and put it under

IAEA safeguards. Thus, this lead to a reverse drain of

technology from India to the US.

This deal posed some serious questions on the legal front

also. Unlike the 123 agreements with china and Japan, this

123 agreement with India didnt have an arbitration clause.

That is, the US could just go away from the deal Scot free

when we would have invested billions of dollars. Thus US

again reinforced that this was not a deal between equalnations but was a lopsided one.

To add to the humiliating list is the clause of perpetual

safeguards not leading to perpetual fuel supply. In simpler

terms, while the reactors that we earmark for civilian nuclear

energy production will be kept under IAEA safeguards for

their entire lifetime, there is no assurances of lifetime fuel

supply in case the deal is broken.This deal could have only

a dream for the American nuclear energy companies which

were running into huge losses. All over the world too (except

France and Russia), governments have shied away from

nuclear energy. Our politicians had forgotten about what

But US responded to the timid fears (which should have

been strong allegations) from the Indian side by resorting to

convoluted wordings in the 123 agreement. In the due course, India

got its safeguards agreement approved in the IAEA, lost the majority

in the parliament, passed the floor test and went to the NSG for an

India-specific waiver so that we could enter into global nuclear

commerce (not just with the US).

India faced stiff resistance in the NSG from the non-

proliferation lobby. While complains about lack of interest in theUS negotiating side were being raised in the Indian media, a potentia

deal buster came in the form of a letter released by the foreign

relations committee of the US senate. This letter contained answers

from the Bush administration to 45 techno-political questions raised

by the congressional committee. The letter, which could be

considered the official stand of US, confirmed our worst fears. (The

letter can be accessed at http://www.hcfa.house.gov /110

press090208.pdf)

But as had been the custom throughout the negotiations, the

Indian side brushed aside the issue, saying India was bound only

by the 123 agreement. (Best contenders for modern day Nero!!)

Finally, under the pressure of the US government and after an Indianassurance on non-proliferation, India-specific waiver was cleared

at Vienna with the government describing it a historic moment and

the opponents claiming loss of sovereignty.

We cant brush aside this deal as being totally off the colour

Many countries, including Pakistan, have been denied one. Come

October there will be no Bush to respond to our allegations or for

that matter during the next forty years. It is upto us to protect our

rights and dignity by being pro-active. JAGO INDIA JAGO!!!


1. The base transit time of a bipolar transistor is 100 ps and

carriers cross the 1.2 micro metre B-C space charge at a speed

of 10^7 cm/s. The E-B jn charging time is 25 ps and the collector

capacitance and resistance are .1 pF and 10 ohms, resp. Wha

is the cutoff frequency?

2. What type of junction is formed in the collector-substrate

junction in epitaxial collector structure?

3. A 4 bit modulo-6 ripple counter uses JK flip-flop. If the

propagation delay of each FF is 50ns, what is the max clk

freq?

4. Whether the signal x(t) = 4 sin 3t + 3 sin (sqrt(3)t) is periodic?

If it is periodic, what is its periodicity?

8/14/2019 Pulse Sep-Oct 2008

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gaiety.....

CROSSWORD

KARTHIK.T, iv year & KARTHICK.R.N, i ii year

Quiz COrner

Sudharshan MG, IV Year

Crossword

Sudharshan MG & Rukmani Ravi, IV year

Winners of July - August 2008 issue

Mail your entries to [email protected]

Exciting prizes await you !

We also welcome well-written articles !


Editors

Principal correspondents

third year journalists

Bharanidharan B & Arun Chekhov I

Saravanan P

Karthyek Rajhaa

Harish Guruprasad

Govind Ramanujam M

Arun S

Arun Goud

Anish A

Visswanath VSindhu A

Sheerapthinath OS

Santhaprakash S

Roopini Dan

Prasanna Kumar TSM

Karthick RN

Ganapathy S

[email protected]

5. 12 signals each band limited to 5 kHz are to be transmitted

over a single channel by FDM. If AM-SSB modulation guard

band of 1 kHz is used, what is the BW of the multiplexed

signal?

6. A super heterodyne receiver is to operate in the frequency

range of 550 KHz 1650 KHz, with IF = 450 kHz. The receiver

is tuned to 700 kHz . What is Cmax / Cmin ratio of the LO?

7. 4 1.2 nC point charges are located in free space at the corners

of a square 4 cm on a side. Find the total potential energy

stored in it.8. A lossless transmission line with a characteristic impedance

of 80 ohm is terminated by a load of 125 ohm. Length of line

= 1.25 lambda. What is the input impedance?

9. A 1 micro Farad cap is shunted by a 1 K ohm resistor

maintained at 300 K. What is the rms noise voltage over the

entire frequency band?

10. A mixer stage has a noise figure of 20 dB. This mixer stage is

preceded by an amplifier which has a noise figure of 9 dB

and an available power gain of 15 dB. What is the overall

noise figure?

ACROSS

1 Murders cop tribe if light signal is transmitted (5,5)

6 Aerial worker turns Nebraska, not applicable (7)

7 A completely succesful storage (4)

8 Mixed up at the end (4)

9 This is the point which marks the end of solidity(7)

13 Non-discrete youth leader offers parallelism (7)

15 F1 (Not racing!) (4)

17 This theory is really big! (4)18 Mongolian leader arranged meet on the outskirts of Amritsar on

current issues (7)

19 Get rid of these and keep doing your work (10)

DOWN

1 Breaking news about the fastest of converters (5)

2 100kbps rat bite?Ouch! (3,4)

3 If you cant catch up with me , youll have to face this

reportedly(5,3)

4 Transistor found in a big fettle (5)

5 Impulse gesture? (5)

10 BASIC ENGLISH for example (8)11 Reverse attractor(6)

12 Openest error in a single stair (3,4)

14 Even,allonge ions need password to enter (5)

16 Harbour sockets (5)

pulse sep-oct 2008

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