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
The official BIMONTHLY magazine of ECEA
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
magazine.pulse@gmail.com
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....
Potential Unleashed by Logic Saturated Engineers
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
The official BIMONTHLY magazine of ECEA
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
Potential Unleashed by Logic Saturated Engineers
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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
......techiesarena
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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
gizmos......
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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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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!!!
The official BIMONTHLY magazine of ECEA
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?
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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 magazine.pulse@gmail.com
Exciting prizes await you !
We also welcome well-written articles !
Potential Unleashed by Logic Saturated Engineers
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
magazine.pulse@gmail.com
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)
top related