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CONTENTS AND CONTRIBUTORS
CONSUMER DEFINES V ALUE
BY ERMIAS K AHSAY
LOW POWER CLOCK MULTIPLIER DESIGN FOR
HEART RATE MONITORING SYSTEM
BY TEMESGHEN TEKESTE
MY TO DO LIST
BY S AMSON GONNETZ
JOB OPPORTUNITIES
BY FILIPOS ABRAHAM &
..
Y OSIEF
WOLDEMARIAM
EDITORS
SEBLE GEBREMEDHIN, M.S. IN
PSYCHOLOGY
ADIAM WOLDEGERGISH, PH.D IN
MOLECULAR BIOLOGY
S AMSON GONNETZ, B.A. IN CIVIL
ENGINEERING
FILIPOS ABRAHAM, M.S, IN SOFTWARE
ENGINEERING AND
Y OSIEF WOLDEMARIAM, B.A. IN
ELECTRICAL ENGINEERING
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AEEC | August 2013 2
Consumer Defines Value
Ever since I was young, I was interested inelectricity, electrical circuits and gadgets. Growing
up I always wished to alleviate the power shortage
that our society, Developed and specially
Developing Countries, faced and wished to
improve the quality of life through technology.
After migrating to Centralia which is in
Washington State I initially attended a community
college to receive an associate degree in general
engineering.
Soon after completing my associate degree, I
realized how quickly modern technology was
changing and decided to continue my education. I
enrolled at Oregon State University (OSU) in
Corvallis, Oregon and completed my degree
focusing on electrical and computer engineering,
specializing in semiconductor processing and
manufacturing. During my third year at OSU, I
worked with a company called Planar Systems,
which manufactures medical, industrial and
commercial display. While working at the
company,
I did research looking at thin film
(Electroluminescent) and light emitting diode (LED).
The focus of this research was to discover which ofthese two electronics products would be better for
back lighting on computers, televisions and mobile
devices. As part of my research, I looked at Thin film
electronic circuitry components that are etched onto
a thin wafer of silicon.
Thin film transistor liquid crystal display circuits
which are made on a thin layer of specially
formulated silicon applied to a glass plate. Each TFT
LCD, Thin-Film-Transistor Liquid-Crystal-Display,unit contains the transistors, wiring and other
components necessary to turn an LCD on or off,
blocking or releasing light. Colors are thus produced
with built-in color filters. Light Emitting Diodes
(LED) is specially formulated semiconductors that
produce light when their electrons are prompted
into moving from a high-energy state to a lower one.
Light is, as a result, produced with much less energy
than light bulbs or CRT’s, Cathode Ray Tube- a
vacuum tube containing one or more electron guns
(a source of electrons or electron emitter) and a
fluorescent screen used to view images. Like TFT
LCD’s, LED displays can contain thousands of units
working together to form an image. Individual LED
units can be colored and you can control the
brightness of LED displays in the same way you can
dim a light bulb. At the conclusion of my research, it
is evident that LED for backlights improves the
quality of display color and image contrast
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AEEC | August 2013 3
compared to thin film. LED backlights also allow
thinner display packages, more tolerant viewing
angles, less energy consumption and longer product
life. As seen today, products that use LED’s such as
flat panel LCD and LED TV’s, mobile devices,
calculators, and other medical and commercial
products dominate the market presently.
After completing my study at OSU, I worked as a
product engineer in marketing and sales branch
interacting directly with consumers to find out what
requirements and needs were present in this fast
growing technology sector. While I was working in
marketing, I began to research and work on my Lean
Six Sigma which is a set of tools and strategies for
process improvement, or a powerful, proven
method of improving processes efficiency and
effectiveness that focuses customer satisfaction.
During my research, I discovered a partner that had
the same interest in Lean Six Sigma. We bother want
to help customers get products they need as fast as
possible and with full customers satisfaction. To do
this, both my partner and I created an enterprise
called Lean-Agile SERVICES INTERNATIONAL (LSI).
Lean-Agile is a business strategy based oncustomer satisfaction and delivering quality
products and service that are: 1) Exactly what
the customer needs, 2) When the customer
needs the product, 3) The amount the customer
requires, 4) Based upon an agreed price and
5)Accomplished with minimum resources.
The term 'Lean' in a business or manufacturing
environment describes a philosophy that
incorporates a collection of tools and techniques
into the business process to optimize time, human
resources, assets, and productivity, while
improving the quality level of products and
services to the customers. Lean is also a principle
that creates and maximizes value through the
elimination of waste. Organizations thus rethink
their end-to-end value chains and find ways to
provide what their customers value better, fasterand with significantly fewer resources than their
competitors and can obviously develop an
unassailable competitive advantage by utilizing the
Lean principle.
My partner and I, further developed and are able to
offer what we believe to be the most effective,
powerful, user friendly, and affordable lean data
management software called Lean Data System
(LDS) or Supplier Quality System. LDS is developed
as a primary tool designed to promote a truly lean,
effective and uniform supplier quality effort. It is
also meant as a single source of supplier quality
issue details, lessons learned, and data to support
key metrics used to identify what issues and
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AEEC | August 2013 4
concerns suppliers need to address and in what
order based on cost and schedule impact or both.
Lean Data System helps companies identify and
resolve their issues within a fraction of the time.
LDS allows companies to focuses on what matters
the most, Safety, Quality, Cost and Schedule inorder to give the best service and product to the
consumer. The essential idea of our company
(LSI) is to maximize customer value while
minimizing waste.
Lean creates more value for customers with fewer
resources.
At the end of the day, companies, large, medium or
small, who will be using this fast growing
technology, will be defined by their customers, the
value of their products and services.
~ Engineer Ermias Kahsay
A
E
E
C
Bringing the best and the brightest together
Hard to reach doesn’t have to mean hard to do
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AEEC | August 2013 5
It is every one's dream to connect and discuss as Eritrean professionals are
spreading to all corners of the world as if to fill the map. As its name
indicates Alpha Eritrean Engineers Magazine is the beginning to motivate
other professionals outside engineering to find a means of connection. It is a
brilliant idea to be Alpha.
There is no green light ready to welcome any one whenever you live abroad.
Hunting professional job is the most challenging. I admit that being focused
and working hard will change Eritrean Diaspora's life sooner or later. But
Alpha Eritrean Engineers Magazine is in the right track and wish to
congratulate those who initiate the idea.
Estifanos Asrat Geotechnical engineering
Thanks for sharing brother. It’s so up lifting to see Eritreans in such a
diverse and intellectual field. I am not sure if the magazine is distributed
and how many copies are printed but since I am in the printing industry,
anything I can do to be any assistant to you and your peers, please, don’t
hesitate to let me know.
Dr. Awet Gherezghiher
ALPHA ERITREAN ENGINEERS
Comments & Suggestions
Page
AE
E
C
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AEEC | August 2013 6
Background
Born and raised in the capital city of Eritrea, I
completed all my studies including myundergraduate degree in Asmara. I received my
Bachelor of Science degree in Electrical Engineering
from University of Asmara. After I completed my
studies, I joined the Eritrea Institute of Technology
and worked as Graduate Teaching Assistant. While
working, not only did I have the opportunity to learn
the challenges of Electrical Engineering but I also
gained experience within the academic sector.
Although my interest in Electrical engineering goes
back to my childhood, during my undergrad studies, I
developed a specific interest in digital electronicsand was eager to advance my studies. Thus, from
September 2010 to May 2012, I studied
Microsystems in Masdar Institute of Science and
Technology and took numerous course related to
circuit design and microelectronic fabrication.
I was very fascinated and encouraged to do research
in circuit design after I successfully designed and
tested a chip during my graduate research work. My
research involved digitally assisted analog/mixed
signal circuit design.
I was exposed to the challenges of designing an
verification of custom analog and digital circuits. CA
tools from Synopsys, Cadence and Mentor graphic
were extensively utilized while working on a chip
My research was to implement an ultra-low powe
clock multiplier to supply a LED driver with a 2MHclock based on a 32 kHz reference. The circuit wa
part of an ultra-low power heart rate monitorin
system which uses pulse oximetry technique. Th
system comprises of a photon to digital converter
LED driver and clock generator, (Figure 1). Thre
chips were designed and fabricated and it was a
inspiring experience to design and test a chip a
masters level. One of the outcomes of the researc
conducted was presented at the International Soli
State Circuit Conference (ISSCC 2013) [1]. Being par
of the research group, I had the privilege tparticipate in the ISSCC 2013 conference which waheld on February, 2013 in San Francisco. I also fullcustom designed chip to appear in the conference from
the Middle East region.
Figure1
Heartrate monitoring system based on pulse
oximetry
The novel aspect of the clock multiplier is that it ha
digital intensive implementation based on Frequency Locked Loop (FLL) architecture whic
allows operation at 0.5V supply voltage with les
than 10 micro Amps of current consumption.
Low power Clock multiplier design for heart rate monitoring
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AEEC | August 2013 7
Power consumption is crucial in low power CMOS
circuit design especially for portable and mobile
devices. Scaling the supply voltage is one of the best
techniques to lower the power dissipation. That is
why the systems power supply was limited to 0.5V.
Another reason is that this voltage is also available
directly from a tiny solar cell. The problems
encountered when designing clock generators at lowsupply voltage is the susceptibility to process,
temperature and supply voltage (PVT) variations.
The designed clock multiplier is robust in the
presence of process, temperature, and supply voltage
variations while avoiding complex calibration oranalog circuits such as band gap voltage references
(Figure 2). It is an integer N-frequency multiplier
based on a Frequency Locking Technique. The main
distinction between Frequency Locked Loop and
Phase Locked Loop is that in FLL the error signal
generated in the loop represents frequency rather
than phase error. In case of PLL the error signal
would be proportional to phase. Generally the
system could be described as a negative feedback
system in which a change in the output frequency
would be counteracted by the restoring behavior ofthe feedback.
The main parameter tracked in the feedback loop i
the frequency of the output clock. The system
constantly keeps track of the output frequency an
generates an error signal by comparing it with
reference word. The system does frequenc
multiplication given by FOUT = FREF N where FREF i
reference frequency, FOUT is the output frequenc
and N is an integer.
Figure2
Architecture of the designed FLL
The forward path of the loop comprises of the digita
comparator followed by a set of filters and a digitall
controlled oscillator. The feedback path is formed b
a frequency detector which generates a digital wor
equivalent to the frequency of the output of the DCO
The frequency detector is analogous to a divider tha
generates a phase equivalent to the output in digitaphase locked loop. Digital circuits were heavil
utilized when implementing the system. Digita
circuits are immune to PVT variations as they onl
have to determine digital logic levels of 0 or 1. Wit
technology change the digital circuits could b
retained. The analog part in the design was th
Digitally Controlled Oscillator, and this part might b
required to be redesigned when moving to anothe
technology.
The FLL is designed to generate a clock wit
frequency of 2.096 MHz generated by a digitally
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AEEC | August 2013 8
controlled oscillator (DCO) as revealed in Figure 2.
The DCO is formed by a digital to analog converter
(DAC) and a current controlled ring oscillator. It is
controlled by a 31 level thermometer coded word.
The thermometer code essentially controls a set of
PMOS switches of the DAC, and by turning on or off
more switches the output phase and frequency of the
DCO is modulated. Since the system is designed tokeep track of the output frequency, a frequency
detector (FD) based on counters is implemented. The
frequency detector counts the number of full cycles
of output clock in one period of the reference clock.
The output of the frequency detector is a 9-bit word
and is added with a reference control word so as to
generate a frequency error signal. A value 32 is
chosen as a reference word that corresponds to the
number of full cycles of 1.048 MHz output clock in
one period of the reference clock with frequency
32.768kHz (note that this frequency is available froma commercial crystal oscillators). The 1.048MHz
signal is obtained by dividing the 2.096MHz clock
from the DCO.
The frequency error is accumulated and filtered to
tune the DCO to the desired frequency. The first
accumulator followed by an adder form a lead lag
filter. In addition to accumulating the error signal the
lead lag filter helps reduce the in band phase noise
and quantization error. The output of the lead lag
filter is fed to a second 18bit accumulator. The
output of the accumulator drives a first order Sigma
Delta modulator. The Sigma Delta modulator has an
input of 18bits and output of 5bits. By its dithering
behavior, the Sigma Delta provides a digital word
with average value that tracks the input 18bit word.
Prior to driving the DCO, the 5bit binary word from
the Sigma Delta is converted to a thermometer code.
The binary to thermometer decoder has a behavior
to change only one bit when its input changes by
only one value, thus insuring monotonicity. The DCOhas a CCO which integrates the filtered control signalto an output clock phase ( ).
All the clock signals All the clock signals that operate
the logical circuits are obtained from the referenc
clock and the output of the DCO. The Sigma Delta i
made to run at a higher frequency from the output o
the DCO to enhance the noise performance of th
system. Synchronization circuits are added in th
system so as not to lose any information when th
signals are traveling across the loop.
In summary, proposed system was PVT toleran
frequency locked loop based clock multiplier fo
heart rate monitoring system operating at ultra-low
power. All the circuit required were simulated at
transistor level and the circuit layout was created. A
chip was fabricated and tested. A test board wa
designed as shown in Figure 3a below and the outpu
of the chip is shown in Figure 3b and 3c. The chip
had the desired performance with results similar t
the post layout simulations. Furthermore, aimportant tool that was used in developing thi
model system is called CppSim (www.cppsim.com
which offers fast behavioral simulation systems. It i
built in c++ based modules and various user define
modules can easily be integrated into its platform
This tool is helpful for Electrical Engineers especiall
those working in circuit design.
Figure 3a
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AEEC | August 2013 9
The tool is called CppSim (www.cppsim.com) which
offers a fast behavioral simulation of systems. It has
built in c++ based modules and various user defined
modules could be easily integrated in to its platform.
It is a helpful tool for Electrical Engineers especially
for those working in circuit design.
Figure 3b
Figure 2b
Figure 3c
References
[1] Alhawari M. et al, “0.5V <4µW CMO
photoplethysmographic heart-rate sensor IC based on a nonuniform quantizer”, ISSCC 2013, Sanfrancisco, CA.
~ Engineer Temesghen Tekeste
Simple facts
The first electric light was made in 1800 by Humphry Davy , an
English scientist. (wiki.answers.com)
Three new and latest mathematical theorems were developed by
an Eritrean high school student Saied Mohammed Ali , who was a
student at Warsay – Yekealo Senior Secondary School. (TesfaNews)
An early form of circuit breaker was described by Thomas Edison
in an 1879 patent application. (Wikipedia)
The compass, a tool used to help aid in finding direction, was
invented in China, during the Han Dynasty between the 2nd
century BC and first century AD. The first compasses were made of
lodestone, a naturally magnetized ore of iron. William Sturgeon
invented the modern compass, which is still used today.
(Wikipedia & invention.yukozimo.com)
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A land of dreamers who walk confidently
in the direction of their dreams
Eritrea purely magnificent
Civil engineering at its best!
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My To-Do Lists
Each day, most of us have personal goals-say,
preparing for an exam, throwing a house party or
going somewhere to attend a family weeding etc, and
we have different techniques of managing our time to
increase our productivity, but at certain point it becomes so difficult that the tasks pile up and with
never ending task lists you tend to procrastinate and
frustrate.
I have a problem with my to-do list. Do you?
Even though I had a difficulty with organizing my
day; I always have a to-do list. I find that if I write
my tasks down, I'm far less stressed because I
know I won't forget anything. It helps me to set
priorities and when I'm done with one task, I canmove right onto the next.
I fall in to all kinds of traps with my to-do lists. I
have lists all over the place. I put short and long
time lists and when I occasionally review them
with my pen against the finished ones I found most
of them are not done or partially done. And the
feeling that I wasn't accomplishing anything
frustrates me some times.
For instance, I always plan to start my day bywaking up at six in the morning, go to Gym or do
some running and then do the rest according to my
to-do lists. But I found walking up at six is really
difficult for me. I've been struggling with this for
years. I don’t know why it is always in the first of
my to-do lists. I know I am not going to wake up
but I write it as my first morning task. Why bother
when I can't do it?
In the morning I think that I can do all my to-do
lists for the day. Once I start checking my e-mail I
get distracted and I spend more time on some o
the tasks that are not listed. So, something goe
wrong with my today’s tasks.
Consequently I can't finish my to-dos and I feel likI haven't done enough for the day. On the othe
hand, there are days that my to-do lists goes we
and I feel that I achieved something and I fee
contented. It boosts me to do more for the nex
day.
I’m more organized at work than at home or mor
productive outside than at home. More organize
when I am doing some other people’s busines
than my own. If cleaning or organizing my home ione of my short to-do lists, most of the time
procrastinate to do it unless someone is coming t
my house. I am sure most of us do, especiall
single people homes are more clean and organize
when they invite someone.
I think keeping your lists fairly short helps manag
your tasks easily. It’s so disappointing at the end o
the day when I see my to do lists with a number o
items on it has only a few or maybe non
accomplished. Being able to manage small achievmore makes me very happy. It works for me and
hope it will work for you too!
~ Engineer Samson Gonets
“Only put off until tomorrow what you
are willing to die having left undone”
― Pablo Picasso
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Engineering-Humour.com
Glass Half Full
Someone who sees a partially filled glass as half full is an
often cited definition of an optimist. Someone who sees
the same glass as half empty is taken to be a pessimist. Ithas been said that someone who sets the glass as poorly
designed, because it is twice as large as it needed to be,
is surely an engineer .
……. Sense of humor from engineer’s prospective
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Alpha Eritrean Engineers Magazine
A E E M
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Current Job OpportunitiesCompanies or Government Jobs Location & Number Closing D
Electrical Engineering
https://jobs.boeing.com/JobSeeker/JobView?reqcode=13-1011857
Innovation Center Project Engineer4/5, 13-1011857, Everett, WA;
October 21, 2
https://jobs.boeing.com/JobSeeker/JobView?reqcode=13-
1011060
Multi-Function Project
Manager/Integrator, 13-1011060,
Everett, WA; October 07, 2
https://jobs.boeing.com/JobSeeker/JobView?reqcode=13-
1014135
Electrical Design and Analysis
Engineer 3/4, 13-1014135, Hill
AFB, UT
September 2
2013
Flight Engineering
https://jobs.boeing.com/JobSeeker/JobView?reqcode=13-010779
Aerodynamics Engineer, 13-
1010779, Huntington Beach, CA September 1
2013 https://jobs.boeing.com/JobSeeker/JobView?reqcode=13-010025
Propulsion Engineer 4/5,
13-1010025, North Charleston, SC
September 0
2013
https://jobs.boeing.com/JobSeeker/JobView?reqcode=13-010026
Propulsion Engineer 3/4, 13-
1010026, North Charleston, SC
September 0
2013
Software Engineer
https://jobs.boeing.com/JobSeeker/JobView?reqcode=13-
1013533
Software Engineer 2/3, 13-
1013533, Herndon, VA November 01,
https://jobs.boeing.com/JobSeeker/JobView?reqcode=13-
1013176
Software Engineer, 13-1013176,
Springfield, VAOctober 24, 2
https://jobs.boeing.com/JobSeeker/JobView?reqcode=13-
1012530
Software Engineer 2/3, 13-
1012530, Saint Louis, MO September 1
2013 https://jobs.boeing.com/JobSeeker/JobView?reqcode=13-
1012576
Software Engineer 3, 13-1012576,
Springfield, VA September 1
2013 Information Technology
https://jobs.boeing.com/JobSeeker/JobView?reqcode=13-
1014008
Computing Security & Information
Protection Specialist 3, 13-
1014008, Saint Louis, MO September 0
2013 https://jobs.boeing.com/JobSeeker/JobView?reqcode=13-
1013542
Network Support Analyst, 13-
1013542, Bristol, United Kingdom
September 3
2013
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AEEC | August 2013 15
The authors
Ermias Kahsay [email protected]
Received AS from Centralia community College in
General Enginering in 1994 & BS from Oregon
State University in Elecrical, Electronics and
Computer Engineering in 2002. Currently he
owns company (business) called Lean Services
International works as senior consultant and
President of Operations.
Temesgen Tekeste [email protected]
received his B.S. in Electrical Engineering from
University of Asmara & MS in Micro-systems in
Masdar Institute of Science and Technology, Abu
Dhab. Currently he is employed by Masdar Istitute
of Science and Technology as a research engineer.
Samson [email protected] received his B.S. in CivilEngineering from San Francisco State University in
California and currently he is studing and in a
process of abtaining a Professional Engineer
licence (PE).
If you need an updated information,
discussions or got an Engineering
experiences that you want share
your knowledge or ideas with your
fellow professionals.
You will find us on
www.linkedin.com/groups/Alpha-
Eritrean-Engineers-Community
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