Download Overview - UMass Amherst

What Electrical & Computer
Engineering Can Do for You?
Science & Engineering Saturday Seminar
23 January, 2010
Marinos N. Vouvakis
[email protected]
Special Thanks to: Baird Soules, Kris Hollot, Maciej
Ciesielski, Wayne Burleson, Pat Kelly, Sandip Kundu,
Russ Tessier
Electrical and Computer Engineering
Who Am I?



Professional:
• Assistant Professor in ECE (5 years at UMass)
• Teaching: Electromagnetics, Mathematics, Antennas
• Research: Computational Electromagnetics & Antennas
Education:
• PhD 2005, The Ohio State University
• MS 2002, Arizona State University
• Dipl. Ing 1999, Democritus University of Thrace, Greece
Personal:
• Hellenic National, Crete
• 33 years old (single)
• Favorite Music: Velvet Underground, Slint, Fugazi
• Favorite Sport: Basketball
• Hobbies: Traditional Greek music, politics, history, play with
my cats.
Electrical and Computer Engineering
2
Seminar Objectives
 Why am I doing this?
 Science vs. Engineering?
 What is Electrical & Computer Engineering?
• What are major ECE sub-areas?
• What are the trends?
 A Closer look at some basic concepts ECE:
• Analog CKTs (sensing & signals)
• Digital (entering the Digital world)
• Wireless (the communications revolution)
 Demos
• Sensing & Transducers (Chris)
• Sampling & Bits (Baird, Marinos)
Electrical and Computer Engineering
3
Why am I participation on this Seminar Series?

The Vision
• I want to make impact on society.
• Engineering is key to a better future for
humans and our environment.

The Problem
• Low engineering enrolments nationwide.
• Alarming enrolment trends.
• Most teachers do not have engineering
background.

A Possible solution
• When incoming students are aware about
engineering is, they are likely to choose it.
• Educate teachers about engineering.
Electrical and Computer Engineering
4
Science and Engineering
Electrical and Computer Engineering
5
Science vs. Engineering
 Science: Why things happen the way they
happen?
 Example: Movement of objects (force, friction,
etc)
 Engineering: Creative problem solving.
• More formally: engineering is the discipline, art and
profession of acquiring and applying knowledge to
design and implement materials, structures, machines,
devices, systems, and processes that realize a desired
objective.
 Example: Wheel!!
Engineering = applied science
Electrical and Computer Engineering
6
Science vs. Engineering (cont’d)
The Taxonomy of Learning
Create
Evaluate
Engineering
Analyze
Apply
Understand
Remember
Q: Can we have engineering without science (or vise-versa)?
Electrical and Computer Engineering
7
Science and Engineering
Instrumentation
Science
Electrical and Computer Engineering
Mathematics
Engineering
8
Science and Engineering (cont’d)
Science
Technology
Society
Engineering
Technology logic = (art/craft)+(knowledge/logic)
Electrical and Computer Engineering
9
Engineering Grand Challenges*
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
Make solar energy economical
Provide energy from fusion
Provide access to clean water
Reverse-engineer the brain
Advance personalized learning
Develop carbon sequestration methods
Engineer the tools of scientific discovery
Restore and improve urban infrastructure
Advance health informatics
Prevent nuclear terror
Engineer better medicines
Enhance virtual reality
Manage the nitrogen cycle
Secure cyberspace
*Source: US. National Academy of Engineering
Electrical and Computer Engineering
10
Electrical & Computer Engineering
Electrical and Computer Engineering
11
What do Electrical and Computer Engineers do?
Electrical and Computer Engineering
12
What do Electrical and Computer Engineers do?
“Any sufficiently advanced technology is indistinguishable from magic.”
http://en.wikipedia.org/wiki/Arthur_C._Clarke
Electrical and Computer Engineering
13
Inside the iPhone 3G
“Any sufficiently advanced technology is indistinguishable from magic.”
http://en.wikipedia.org/wiki/Arthur_C._Clarke
Electrical and Computer Engineering
14
What do Electrical and Computer Engineers do?
Electrical and Computer Engineering
15
Electrical and Computer Engineering
 “Electrical engineering is an engineering discipline
that deals with the study and/or application of
electricity, electronics and electro-magnetism.”
 “Computer engineering is a discipline that
combines elements of both electrical engineering
and computer science. Computer engineers are
involved in many aspects of computing, from the
design of individual microprocessors, personal
computers, and supercomputers, to circuit design.”
 Easier to understand by exploring example systems
Electrical and Computer Engineering
16
Electrical Engineering
 Electronics
• Circuit Analysis
• Electronics
 Control
 Fields & Waves
•
•
•
•
Electromagnetics
Microwaves/RF
Optics/Photonics
Antennas/Remote Sensing
• Control Theory
• Power Systems
• Power Electronics
Electrical and Computer Engineering
17
Electrical Engineering
 Communications
•
•
•
•
Communication Systems
Wireless Comm.
Antennas/Radio Wave Propagation
Microwaves and RF
 Signal Processing
• Signals and Systems
• Signal Processing & Communications
• Image Processing
Electrical and Computer Engineering
18
Electrical Engineering
 Semiconductor Technologies
•
•
Solid State Physics
Nano-electronics
32nm TRIGATE Transistor: 2005
First Transistor: 1947
 Microelectronics
• VLSI Ckts
• Embedded Ckts
• Fabrication Technologies
Electrical and Computer Engineering
Pentium processor19
Computer Engineering
 Computer Programming Software
• Algorithms
• Computer Graphics
 Computer Design
• Hardware Organization & Design
• Embedded Systems Systems
• Computer Architecture
Electrical and Computer Engineering
20
Computer Engineering
 Networking
• Computer Networks & Internet
• Cryptography
• Trustworthy Computing
 Bioengineering
• Bio-informatics
• Bio-sensors
• Bio-electronics
Electrical and Computer Engineering
21
EE/CE Salary
 In Electrical Engineering salary rises fast with
experience
• Mobility, Flexibility, Job Satisfaction among highest
 Do not focus just on starting salaries
 EETIMES salary survey 2006
Electrical and Computer Engineering
22
Job Satisfaction: EETIMES Survey
Electrical and Computer Engineering
23
Future ECE Job Prospects*



Computer hardware engineers are expected to have employment growth of 4 percent
over the projections decade, for all occupations. Although the use of information
technology continues to expand rapidly, the manufacture of computer hardware is
expected to be adversely affected by intense foreign competition. As computer and
semiconductor manufacturers contract out more of their engineering needs to both domestic
and foreign design firms, much of the growth in employment of hardware engineers is
expected to take place in the computer systems design and related services industry.
Electrical engineers are expected to have employment growth of 2 percent over the
projections decade. Although strong demand for electrical devices including electric
power generators, wireless phone transmitters, high-density batteries, and navigation
systems should spur job growth, international competition and the use of engineering
services performed in other countries will limit employment growth. Electrical engineers
working in firms providing engineering expertise and design services to manufacturers
should have better job prospects.
Electronics engineers, are expected to experience little to no employment change over
the projections decade. Although rising demand for electronic goods including
communications equipment, defense-related equipment, medical electronics, and consumer
products should continue to increase demand for electronics engineers, foreign
competition in electronic products development and the use of engineering services
performed in other countries will limit employment growth. Growth is expected to be fastest
in service-providing industries particularly in firms that provide engineering and design
services.
*Bureau of Labor & Statistics
Electrical and Computer Engineering
24
Electrical & Computer Engineering Systems
An advanced “engineering” system
React
Electrical and Computer Engineering
25
Analog Electrical CKTs
(Sensing & Power)
React
Electrical and Computer Engineering
26
Charge & Electric Current
 Each electron carries an electrical charge,
q of –1.602x10-19 coulombs [C]
 1 [C] = the charge of 6.242x1018 electrons
 Current, I or i
• flow rate of electrical charge through a
conductor or a circuit element
• Unit: ampere [A]. 1A=1C/s
• Current-charge relationship:
d
i (t )  q(t )
dt
Electrical and Computer Engineering
27
Direct Current (DC) & Alternating Current (AC)
 DC
• Current that is constant with time
• For examples, I=3A or V=12V
 AC
• Current that varies with time and
reverses its direction periodically
(sinusoidal)
• For example,
Thomas Edison
(1847 – 1931)
v(t)  VP cos 2 ft 
Nikola Tesla
(1856 – 1943)
Electrical and Computer Engineering
28
Water-Model Analogy
 We cannot see electric current flowing in a wire
 Water-model or fluid-flow analogy helps us
visualize the behaviors of electrical circuits and
elements
 Electric Current = flow of electrical charges
 (Water) Current = flow of water molecules
 Assumptions
wire / pipe
• Frictionless pipes
• No gravity effect
• Incompressible water
i(t)
cross section
Electrical and Computer Engineering
29
Material Types
 Conductors
• Electric currents flow easily.
• Examples: copper, gold, aluminum…
 Insulators
• Do not conduct electricity.
• Examples: ceramics, plastic, glass, air…
 Semiconductors
• Sometimes conductors, sometimes insulators
• Examples: silicon, germanium
• Applications: transistors
 Superconductors
• Perfect conductors when cooled
• Applications: MRI, astronomy
Electrical and Computer Engineering
30
Voltage
 Voltage
• Measured between two points (terminals)
• Energy transferred per unit of charge that
flows from one terminal to the other
• Intuitive interpretations: potential difference,
water pressure in water model
• Variable: v(t ), Vin ,Vout ,V1 ,V2 
• Unit: volt [V]
Alessandro Volta
(1745 – 1827)
 Water models
• For constant voltage sources
• Constant-pressure water pump
• Constant-torque motor
Electrical and Computer Engineering


31
Rules of Current Flow - Kirchhoff’s Current Law
 Kirchhoff’s current law (KCL)
N
i
• Conservation of electrical currents
n 1
• The sum of all the currents into a node is zero
• The sum of the currents entering a node equals the
sum of the currents leaving a node
n
(t )  0
node
i3
i1
i2
i1  i2  i3  0
i1  i2  i3
Electrical and Computer Engineering
i3
i1
i2
Gustav Kirchhoff
(1824 – 1887)
32
Rules of Current Flow - Kirchhoff’s Voltage Law
N
v
 Kirchhoff’s voltage law (KVL)
n
(t )  0
• Conservation of energy
n 1
• The sum of the voltages around any closed path (loop)
is zero
loop 3
 Example
+1 _
3+
Loop 1 : 1V  5V  3V  9V  0
+
5_
loop 2
+
12
_
+4
_
loop 1
_
+
9_
_3 +
Loop 2 :  3V  12V  4V  5V  0
Loop 3 : 1V  3V  12V  4V  3V  9V  0
Electrical and Computer Engineering
33
CKT Components - The Resistor
 Resistor
• Electrical component that resists the current flow
• Variable: R [ohm] or 
 
 Water models for a resistor
R
~
=
R
constriction
Electrical and Computer Engineering
R
sponge
34
Resistors in Practice
Incandescent
Light Bulb
Resistive Touch-screen
Electrical and Computer Engineering
Power Supplies
35
Rules of Current Flow - Ohm’s Law
v(t )  i (t ) R
 Ohm’s Law
i (t )
+
v(t)
R
_
v (t )
 Power dissipated in a resistor
i(t)
Georg Ohm
(1789 – 1854)
2
v
(t )
2
p(t )  i(t ) v(t )  i (t ) R 
R
Electrical and Computer Engineering
36
Resistors in Series
+
v (t )
_
i (t )
R1
+ v1 _
+
+
v2
_ v3 + _
R2
=
i (t )
v (t )
+
_
Req
_
R3
KCL : i(t )  i1 (t )  i2 (t )  i3 (t )
KVL : v(t )  v1 (t )  v2 (t )  v3 (t )
Ohm' s Law : v(t )  i(t ) R1  i(t ) R2  i(t ) R3  i(t )( R1  R2  R3 )
v(t)  i(t)Req
Electrical and Computer Engineering

Req  R1  R2  R3
37
Resistors in Parallel
+
v (t )
i (t )
i1 (t )
i2 (t )
R1
_
+
i3 (t )
R2
R3
=
v (t )
i (t )
+
_
Req
_
KCL : i(t )  i1 (t )  i2 (t )  i3 (t )
KVL : v(t )  v1 (t )  v2 (t )  v3 (t )
1 1
v(t ) v(t ) v(t )
1 
Ohm' s Law : i(t ) 


 v(t )   
R1
R2
R3
 R1 R2 R3 
v(t)
1
i(t) 
 Req 
Req
1 R1  1 R2  1 R3
Electrical and Computer Engineering
38
CKT Components - The Capacitor
 Capacitor & Capacitance
• Stores energy through storing charge
• Construction: separating two sheets of
conductor by a thin layer of insulator
• Variable: C
• Unit: Farad [F]. 1F=1 coulomb per volt
Michael Faraday
(1791-1867)
C
q(t )  Cv(t )
Electrical and Computer Engineering
capacitor
39
CKT Components - The Capacitor (cont’d)
_
+ v (t )
i(t)
CKT Model:
+
+
+
+
+
+
_
_
_
_
_
_
electron flow
Water Model:
piston
Electrical and Computer Engineering
spring
40
Capacitor Equations
dv(t)
i(t)  C
dt
 Current:
i (t )
C
 Voltage:
+
v_(t )
t
1
v(t )   i(t )dt  v(t 0 )
C t0
 Energy Stored:
1 2
e(t)  Cv (t)
2
MATH (Integration) = CKT (capacitor) !!!
Electrical and Computer Engineering
41
Basic Capacitors Arrangements
i (t )
+
i (t )
i1
Parallel:v (t )
i3
i2
C2
C1
+
C3
v (t )
_
+
_
C1
i (t )
+ v
1
Series:
v (t )
_
+
_ C C C C
eq
1
2
3
+
_
+
v2
v
_ 3+ _
C3
Electrical and Computer Engineering
C2
v (t )
_
+
_
1
1
1
1



Ceq C1 C2 C3
42
CKT Components - The Inductor
• Stores energy through storing magnetic field
• Construction: coiling a wire around some type
of form
• Variable: L [Henry] or [H].
• When the electric current changes in the coil,
it creates a magnetic field around the wire
which induces voltage across the coil
i (t )
Joseph Henry
(1797-1878)
+
L
v (t )
_
Electrical and Computer Engineering
43
CKT Components - The Inductor (cont’d)
 Operation
• When the electric current changes in the coil, it creates
a magnetic field around the wire which induces voltage
across the coil
d
v(t )  L i (t )
dt
 Water model analogy



Electrical and Computer Engineering


Bi-directional turbine
driving a flywheel
Passive, driven by
current; no motor
Momentum
44
Inductor Equations
 Current:
t
1
i(t )   v(t )dt  i(t 0 )
L t0
 Voltage:
d
v(t )  L i (t )
dt
 Energy Stored:
1 2
e(t)  Li (t)
2
i (t )
+
L
v (t )
_
MATH (differentiation) = CKT (inductor) !!!
Electrical and Computer Engineering
45
Basic Inductor Arrangements
i (t ) L1
+
+ v1 _
Parallel: v (t )
_ v3
_
+
+
v2 L2
v (t )
+
_
_
i (t )
Leq  L1  L2  L3
L3
+
Series: v (t )
i (t )
+
L1
L2
_
Electrical and Computer Engineering
L3
v (t )
i (t )
1
1
1
1



Leq L1 L2 L3
_
46
CKT Components - The Transistor



Transistor is active component (generates energy)
Controls the flow of currents
Construction: combine semiconductor materials
(many different implementations)

The key element in any ECE application
C (collector)
B (base)
John Bareen
Walter Brattain
William Shockley
(1947)
E (emitter)
Electrical and Computer Engineering
*Julius Edgar Lilienfield (1925)!!
47
Transistor Operation
 Use base voltage to control current flow on collector
• Amplification (analog CKTs)
• Switching (digital CKTs)
C (collector)
1
B (base)
0
E (emitter)
Electrical and Computer Engineering
switch
amplifier
48
Circuit Schematics
connection
wires
R
resistor
+
V
battery
no connection
+
_
V
voltage
source
I
current
source
L
C
terminals
ground
Electrical and Computer Engineering
capacitor
inductor
transistor
49
An Analog CKT System
High-End Sound Amplifier
CKT design
Hardware Implementation
Electrical and Computer Engineering
50
Digital Electrical CKTs
(Process)
React
Electrical and Computer Engineering
51
The Digital World
 Biological Systems:
1 agccccagtc agcgtcacca cgccgtatgt
61 cctctactgc agtaaactgc tggacctggc
121 ggaggctgag tttgatgtgc taaaggtctt
181 ctcccagaag cggatccgtg tggccgtggt
241 cgacctcagg gacaggaagc agccttcgga
ggaggacatc
cttcctgctg
tgtggtggac
ggagtaccac
gctgcggcgc
tcagagccgc
gacggctcct
atgatggagc
gatggctcgc
atcgctggtc
ccctgcatga
ccaagctgtc
ggctgcacat
actcctacat
aggtgaagta
 Electrical Systems:
1 01000101 00101011 11010010
61 00111011 00101110 00010000
121 10101010 00110111 11000110
181 00000000 11011101 01011110
241 00101011 01010111 01011110
Electrical and Computer Engineering
11110011
00000001
01011100
00101111
00101010
01111000
10000000
01110001
00010010
10000101
00101101
01101111
00111011
10010100
01011010
52
The Digital World
 Biological Systems:
 Electrical Systems:
Electrical and Computer Engineering
53
Binary in History
Yin-Yang Emblem
Pa Kua: Eight Trigrams
G. Leibniz
(1646-1716)
 Binary exists for thousand of years in ancient Chinese
history: yin-yang
8 trigrams
64 hexagrams
 G. Leibniz, 1679: formal development of the system of
binary arithmetic
Electrical and Computer Engineering
54
Signal, Signals, Signals
Continuous
-Time
(Space)
Continuous-Amplitude
Discrete-Amplitude
x(t)
x(t)
t
t
Local telephone, cassettetape recording,photograph
telegraph
x[n]
Discrete
-Time
(Space)
x[n]
n
Switched capacitor filter,
speech storage chip, halftone photography
Electrical and Computer Engineering
n
CD, DVD, cellular
phones, digital camera &
camcorder
55
Why Digital?
 Robust
(less susceptible to noise)
 Simple
(deals with 0s & 1s)
Electrical and Computer Engineering
56
Entering and Exiting the Digital World…
Electrical and Computer Engineering
57
Entering and Exiting the Digital World… (cont’d)
Electrical and Computer Engineering
58
Sampling
^x(t)
x(t)
t
t
 Increases the sampling rate and the
amplitude resolution by a factor of 2
^
x(t)
x(t)
Electrical and Computer Engineering
t
t
59
Sampling (cont’d)
 Sampling rate:
• How fast should we sample?
• Fewer samples are needed for a slowly-changing signal.
More samples are required for fast-changing signals
• What is the critical sampling rate?
 Consider the sampling of a simple sinusoid
300Hz
700Hz
Sampling rate: 1000Hz
Electrical and Computer Engineering
60
Sampling (cont’d)
 Aliasing
• Ambiguity in the reconstruction: 700Hz sinusoid can be
mistakenly identified as a 300Hz sinusoid in example
• Generally, aliasing error results from not having enough
samples for fast-changing signals
• To avoid aliasing, sample fast enough!
700Hz
Sampling rate increases to: 1400Hz
Electrical and Computer Engineering
61
Sampling & Aliasing in Digital Images
Electrical and Computer Engineering
62
Example: Digital Audio
processing or storage of
digital signal (e.g., MP3)
Electrical and Computer Engineering
63
Analog to Digital Recording Chain
ADC
• Microphone converts acoustic waves to electrical
energy. It’s a transducer.
• Analog signal: continuously varying electrical energy of
the sound pressure wave.
• ADC (Analog to Digital Converter) converts analog to
digital electrical signal.
• Digital signal: digital representation of signal in binary
numbers.
• DAC (Digital to Analog Converter) converts digital signal
in computer to analog for your headphones.
Electrical and Computer Engineering
64
Digital Quantization
3-bit quantization: use 3 bits to represent values 0,1,…7
7
Amplitude
6
5
4
3
2
1
0
Measure amplitude at each tick of sample clock
5
6
7
7
Electrical and Computer Engineering
5
4
3
1
2
5
7
5
7
Time
4
65
Decimal-Binary Conversion
 Divide the decimal number
repeatedly until the quotient is
zero. The remainders in reverse
order give the number’s equivalent
binary form
343 10 = 101010111 2
1 x 2 8 + 0 x 27 + 1 x 2 6 + 0 x 2 5+ 1 x 2 4
0
+ 0 x 2 3+ 1 x 2 2 + 1 x 2 1 + 1 x 2 = 343
Electrical and Computer Engineering
Quotient Remainder
343/2
171
1
171/2
85
1
85/2
42
1
42/2
21
0
21/2
10
1
10/2
5
0
5/2
2
1
2/2
1
0
1/2
0
1
66
The Digital Audio Stream
 A series of sample numbers, to be interpreted as
instantaneous amplitudes
• one number for every tick of the sample clock
From previous example:
5
6
7
7
5
4
3
1
2
5
7
5
7
4
 This is what appears in a sound file, along with a header that
indicates the sampling rate, bit depth and other things
 Each number is then converted to binary and stored in a
register
101
110
111
111
101
Electrical and Computer Engineering
100
101
001
010
101
111
101
111
100
67
Examples of quantization vs. resolution
256x256, 8 bit, 64 kB
256x256, 4 bit, 32 kB
256x256, 2 bit, 16 kB
256x256, 1 bit, 8 kB
64x64, 8 bit, 4 kB
Lower resolution
Electrical and Computer Engineering
68
Digital Technology: DVD
Digital Versatile Disc or Digital Video Disc
First appeared in the US market in March 1997
Employ the same red laser as in CDs
Higher-density multi-layer discs to improve storage
capacity
 DVD Audio: 192-kHz 24-bit sampling rate!




Electrical and Computer Engineering
69
Digital Technology: DVD
Specification
CD
DVD
Track Pitch
1600 nm
740 nm
Min. Pit Length
830 nm
400/440 nm
Storage Capacity
780 MB
4.38-15.9 GB
Electrical and Computer Engineering
70
Binary Logic - Logic Gates
Electrical and Computer Engineering
71
Binary Arithmetic - Addition
 Simple observation
Addition
Binary
Decimal
0+0=0
0+0=0
0+1=1
0+1=1
1+0=1
1+0=1
1+1=10
1+1=2
Electrical and Computer Engineering
72
Binary Arithmetic - Addition (cont’d)
Truth Table of Half-Adder
Inputs
A
B
Sum
Carry
 What about n-bit inputs?
Electrical and Computer Engineering
Outputs
A
B
Sum
Carry
0
0
0
0
0
1
1
0
1
0
1
0
1
1
0
1
XOR
AND
73
Principle of Binary Addition
 Binary addition
• Very similar to decimal addition
• Starting from least significant bit (LSB), keep track of
partial sum & carry until reaching most significant bit
(MSB)
• Simpler than decimal addition: only 0 and 1 are involved
 Example
111110 0
1101100
carry
+
MSB
1011101
11001001
Binary Addition
Electrical and Computer Engineering
+
LSB
11
108
carry
93
201
Decimal Addition
74
Binary Arithmetic - Addition the Full Adder
Inputs
 We need to add three
bits (A, B, and Carry),
not two as in the halfadder
 This is called a full
adder Ai Bi
Carry-out
Co
FA
Sum
S
Electrical and Computer Engineering
Carry-in
Ci
Outputs
Ai
Bi
Ci
S
Co
0
0
0
0
0
0
0
1
1
0
0
1
0
1
0
0
1
1
0
1
1
0
0
1
0
1
0
1
0
1
1
1
0
0
1
1
1
1
1
1
75
Binary Arithmetic - the N-bit Full Adder
A7 B7 A6 B6 A5 B5 A4 B4 A3 B3 A2 B2 A1 B1 A0 B0
Co
Ci
S8
S7
S6
S5
S4
S3
S2
S1
S0
8-bit Full Adder
last carry out,
overflow bit
first carry in,
set to 0 here
CKT = MATH (= $$$$$)
Electrical and Computer Engineering
76
The Systems Approach
(divide and conquer)
Electrical and Computer Engineering
77
System - An external view
System
(Perform Function)
Inputs
Outputs
System: A collection of interacting elements that form an
integrated whole
Electrical and Computer Engineering
78
Digital Hardware Building Block Hierarchy
 Digital system (1)
 Circuit board (1-4)
 Chip (5-100)
 Logic gate (1k-500k)
 Transistor (1M-10M)
Electrical and Computer Engineering
79
PC Motherboard Level
I/O bus slots
Electrical and Computer Engineering
Disk & USB interfaces
Processor
interface
Memory
Processor
Graphics
80
Chip Level (Pentium 4 Processor)
Electrical and Computer Engineering
81
Logic Gate Level
NAND Gate Chip
Electrical and Computer Engineering
82
Transistor Level
Capacitor
M1 word
line
Metal word line
SiO2
Poly
n+
Field Oxide
n+
Poly
Inversion layer
induced by
plate bias
Cross-section
Diffused
bit line
Polysilicon
gate
Polysilicon
plate
Layout
Uses Polysilicon-Diffusion Capacitance
Electrical and Computer Engineering
83
Software
 Software
• Contains instructions for the computer to accomplish certain
tasks
• Flexible, easy to modify, copy, and transport
 Data manipulations
• Arithmetic operations: additions, multiplications, logarithms,
trigonometric functions…
• Logic operations: from OR, AND, NOT to complex logic
functions…
• Conditional operations: if then else…
 For ECE research and development
• Matlab, Mathematica, Maple, Mathcad, Labview, Cadence,
develop our own software using programming languages such
as C++, Java, FORTRAN…
Electrical and Computer Engineering
84
Software Building Block Hierarchy
 Assembly code
• Most basic low-level programming codes
• Different and need to be optimize per processor type
 Operating System (OS)
• Set of basic instructions for I/O, file system, resource
sharing, security, graphical user interface (GUI)
• UNIX/Linux, Windows, MS-DOS, MacOS…
 High-level programming language
• Provide more general, more powerful, more abstract
instructions for the computer
• Visual BASIC, FORTRAN, C, C++, Java…
 Application
MOV 520 R0
ADD R0 R1
UNIX: ls –l
rm *.*
DOS: dir
del *.*
C++: x++
Fortran: x=x+1
• User-friendly software package for popular applications
• Word processors, email & web browser, games…
Electrical and Computer Engineering
Word
Explorer
Sims
85
Communication CKTs
(Sense/React)
React
Electrical and Computer Engineering
86
Cell Phone

A cell phone is a very complex system that can receive input signals in
various forms (electromagnetic waves from base station, sound from
microphone, text from key pad) and convert them to several desired types
of output signals (sound through speaker, electromagnetic waves to base
station, graphics to screen)
Electrical and Computer Engineering
87
Cell Phones: Inside
front
microprocessor
Electrical and Computer Engineering
back
flash memory
LCD & keypad
speaker, microphone
88
Cell Phone System
Electrical and Computer Engineering
89
Sound Fundamentals



Electrical and Computer Engineering
Sound waves:
vibrations of air
particles
Fluctuations in air
pressure are
picked up by the
eardrums
Vibrations from
the eardrums are
then interpreted
by the brain as
sounds
90
Harmonics in Music Signals



Electrical and Computer Engineering
The spectrum of a single note
from a musical instrument
usually has a set of peaks at
harmonic ratios
If the fundamental frequency is f,
there are peaks at f, and also at
(about) 2f, 3f, 4f…
Best basis functions to capture
speech & music: cosines & sines
91
Frequency
 How fast a vibration happens
• High frequency -> fast vibration (voice/music: soprano)
• Low frequency -> slow vibration (voice/music: baritone)
 The frequency f is the inverse of the period T
 Sinusoidal frequency
 Units
1
f 
T
1 
f  
T 2
• Period: second (unit of time)
• Frequency: 1/sec or hertz [Hz]
• Phase: radians
Electrical and Computer Engineering
92
Music Signals: Piano
Electrical and Computer Engineering
93
Frequency Spectrum - Audio
0
0
Human Auditory System
20Hz-20kHz
10k
FM Radio Signals
100Hz-12kHz
10k
20k
20k
AM Radio Signals
100Hz-5kHz
0
10k
20k
f (Hz)
f (Hz)
f (Hz)
Telephone Speech f max  3.3kHz  f sampling  6.6kHz
300Hz-3.5kHz
f (Hz)
0
10k
20k
Electrical and Computer Engineering
94
Frequency Spectrum - Music Signals
  2f  fundamenta l frequency
x(t )  cost   0.75 cos3t   0.5 cos5t  
0.14 cos7t   0.5 cos9t   0.12 cos11t   0.17 cos13t 
Electrical and Computer Engineering
95
Transmitting & Receiving Information via Electromagnetic
Aeronautical comm
120 - 130 MHz
Maritime comm
157 - 162 MHz
VHF wireless, TV
169 - 600 MHz
Cellular phones
900, 1800, 2400 MHz
Detection of buried
land mines
(900 - 2000 MHz)
Microwave imaging
of tumors
1100 - 1200 MHz
Radio astronomy
1413 MHz
Microwave ovens
2400 MHz
Bluetooth wireless
2400 MHz
Global position sat
1600, 1200 MHz
Airport appr. radar
2700 MHz
Satellite weather
12 GHz
Satellite TV
14 GHz
Satellite comm
20 - 22 GHz
Adv. environ. radars
37, 98, 220 GHz
Small size devices
Large Bandwidth
Large antenna gain
Small penetration
Large resolution
Large size devices
Small bandwidth
Small antenna gain
Large penetration
Small resolution
Electrical and Computer Engineering
c

f
c : speed of light
f : frequency
96
Modulation
Electrical and Computer Engineering
97
Modulation (cont’d)
 Modulation
• Using higher-frequency sinusoids to carry signals
• More efficient transmission & allow multi-user sharing
 Pulse modulation
Morse code,
infrared remote control…
 Amplitude modulation
AM radio stations,
video part of TV signals…
 Frequency modulation
FM radio stations,
Cell phones, cordless phones…
Electrical and Computer Engineering
98
Radio Frequency Systems
An advanced RF /microwave system
waveguidePA
T/R
Antenna
switch
LNA
Mixer VCO
DSP/
A/D
Processor
LO
Power
Supply
Electrical and Computer Engineering
99
Modem Transmission
 Frequency-shift keying (FSK)
• Uses analog sinusoids of different frequencies to carry digital
signals
0
1
0
Transmit
0
1
Receive
frequency
300
1070 1270
0
Electrical and Computer Engineering
1
2025 2225
0
3300
1
100
Cell Phones
Frst cell phone 1973 DynaTAC 1983 Motorola Razr
Sony Ericsson
Xperia X1
Nokia N96
Electrical and Computer Engineering
Google G1
BlackBerry
Apple iPhone
101
The Cell Approach
 Cellular telephone system is
based on the principle of
radio communication
 Coverage area is divided into
hexagonal cells (each covers
around 10 square miles)
 Non-adjacent cells can reuse
the same frequencies
 Low-power transmitters:
both phones & base stations
 Each city has a Mobile
 Each carrier: 832 radio frequencies
Telephone Switching Office
 Duplex system: 395 voice channels &
(MTSO)
42 control channels

Each cell: 56 voice channels
Electrical and Computer Engineering
102
From Cell to Cell
 System Identification
(SID) code to check for
available service
 MTSO uses the control
channels to identify where
the user is & assign
frequencies
 MTSO handles the handoff switching between cells
based on signal strengths
 Everything happens within
seconds or even less!
Electrical and Computer Engineering
103
Cell Phone Tower
Antenna Array
Switching, RF and Power
Electronics
Electrical and Computer Engineering
104
What Next?
1. Connect & collaborate with UMass Amherst ECE faculty
1. Teacher development grants
2. Summer research experience for teachers
2. Recommend exceptional high-school juniors/seniors
summer research at UMass.
3. Invite UMass Profs to High-school student seminars.
4. M5 Open house for students and Teachers.
5. Spread the word to students & colleagues.
6. Participate on upcoming ECE SESS(more in-depth).
Marinos N. Vouvakis
[email protected]
Electrical and Computer Engineering
105
Disclaimer
Some materials (drawings, figures, text) presented
in these slides was obtained from the following web
resources:
1.
2.
3.
4.
5.
6.
7.
8.
http://images.google.com/imghp?hl=en&tab=wi
http://www.ecs.umass.edu/ece/engin112/
http://thanglong.ece.jhu.edu/Course/137/Lectures/
http://www.ecs.umass.edu/public/ece_docs/ECE_303_
syllabus_S09.pdf
http://www.nae.edu/
http://www.bls.gov/oco/ocos027.htm#outlook
http://www.engtrends.com/IEE/0806D.php
http://www.eetimes.com/news/latest/showArticle.jhtml
?articleID=206903802
Electrical and Computer Engineering
106