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What Electrical & Computer Engineering Can Do for You?

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1 What Electrical & Computer Engineering Can Do for You?
Science & Engineering Saturday Seminar 23 January, 2010 Marinos N. Vouvakis Special Thanks to: Baird Soules, Kris Hollot, Maciej Ciesielski, Wayne Burleson, Pat Kelly, Sandip Kundu, Russ Tessier

2 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.

3 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)

4 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.

5 Science and Engineering

6 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

7 Science vs. Engineering (cont’d)
The Taxonomy of Learning Create Engineering Evaluate Analyze Apply Understand Remember Q: Can we have engineering without science (or vise-versa)?

8 Science and Engineering
Observation Science First Principles Instrumentation Mathematics Engineering Intuition

9 Science and Engineering (cont’d)
Beliefs/behaviors Technology Society Engineering Technology logic = (art/craft)+(knowledge/logic)

10 Engineering Grand Challenges*
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

11 Electrical & Computer Engineering

12 What do Electrical and Computer Engineers do?

13 What do Electrical and Computer Engineers do?
“Any sufficiently advanced technology is indistinguishable from magic.”

14 Inside the iPhone 3G “Any sufficiently advanced technology is indistinguishable from magic.”

15 What do Electrical and Computer Engineers do?

16 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

17 Electrical Engineering
Electronics Circuit Analysis Fields & Waves Electromagnetics Microwaves/RF Optics/Photonics Antennas/Remote Sensing Control Control Theory Power Systems Power Electronics

18 Electrical Engineering
Communications Communication Systems Wireless Comm. Antennas/Radio Wave Propagation Microwaves and RF Signal Processing Signals and Systems Signal Processing & Communications Image Processing

19 Electrical Engineering
Semiconductor Technologies Solid State Physics Nano-electronics 32nm TRIGATE Transistor: 2005 First Transistor: 1947 Microelectronics VLSI Ckts Embedded Ckts Fabrication Technologies Pentium processor

20 Computer Engineering Computer Programming Software Computer Design
Algorithms Computer Graphics Computer Design Hardware Organization & Design Embedded Systems Systems Computer Architecture

21 Computer Engineering Networking Bioengineering
Computer Networks & Internet Cryptography Trustworthy Computing Bioengineering Bio-informatics Bio-sensors Bio-electronics

22 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

23 Job Satisfaction: EETIMES Survey

24 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

25 Electrical & Computer Engineering Systems
An advanced “engineering” system React

26 Analog Electrical CKTs
(Sensing & Power) React

27 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:

28 Direct Current (DC) & Alternating Current (AC)
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) Nikola Tesla (1856 – 1943)

29 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 Frictionless pipes No gravity effect Incompressible water i(t) wire / pipe cross section

30 Material Types Conductors Insulators Semiconductors Superconductors
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

31 Voltage Voltage Water models 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: Unit: volt [V] Water models For constant voltage sources Constant-pressure water pump Constant-torque motor Alessandro Volta (1745 – 1827)

32 Rules of Current Flow - Kirchhoff’s Current Law
Kirchhoff’s current law (KCL) Conservation of electrical currents 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 Gustav Kirchhoff (1824 – 1887) node

33 Rules of Current Flow - Kirchhoff’s Voltage Law
Kirchhoff’s voltage law (KVL) Conservation of energy The sum of the voltages around any closed path (loop) is zero Example loop 3 1 5 3 9 + _ 12 4 loop 1 loop 2

34 CKT Components - The Resistor
Electrical component that resists the current flow Variable: R [ohm] or Water models for a resistor R constriction R R sponge = ~

35 Incandescent Light Bulb
Resistors in Practice Resistive Touch-screen Power Supplies

36 Rules of Current Flow - Ohm’s Law
Power dissipated in a resistor Georg Ohm (1789 – 1854) R v(t) _ + i(t)

37 Resistors in Series + _ + _ =

38 Resistors in Parallel + _ + _ =

39 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 ( ) capacitor C

40 CKT Components - The Capacitor (cont’d)
+ _ i(t) electron flow CKT Model: Water Model: piston spring

41 Capacitor Equations Current: + Voltage: C _ Energy Stored:
MATH (Integration) = CKT (capacitor) !!!

42 Basic Capacitors Arrangements
+ _ + _ Parallel: + _ + _ Series:

43 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 + _ L Joseph Henry ( )

44 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 Water model analogy Bi-directional turbine driving a flywheel Passive, driven by current; no motor Momentum

45 Inductor Equations Current: + Voltage: L Energy Stored: _
MATH (differentiation) = CKT (inductor) !!!

46 Basic Inductor Arrangements
+ _ + _ Parallel: + _ + _ Series:

47 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) John Bareen Walter Brattain William Shockley (1947) B (base) E (emitter) *Julius Edgar Lilienfield (1925)!!

48 Transistor Operation Use base voltage to control current flow on collector Amplification (analog CKTs) Switching (digital CKTs) C (collector) 1 B (base) amplifier switch E (emitter)

49 Circuit Schematics connection no connection wires R + + V _ V I
resistor battery voltage source current source L C terminals inductor ground capacitor transistor

50 An Analog CKT System High-End Sound Amplifier CKT design
Hardware Implementation

51 Digital Electrical CKTs
(Process) React

52 The Digital World Biological Systems: Electrical Systems:
1 agccccagtc agcgtcacca cgccgtatgt ggaggacatc tcagagccgc ccctgcatga 61 cctctactgc agtaaactgc tggacctggc cttcctgctg gacggctcct ccaagctgtc 121 ggaggctgag tttgatgtgc taaaggtctt tgtggtggac atgatggagc ggctgcacat 181 ctcccagaag cggatccgtg tggccgtggt ggagtaccac gatggctcgc actcctacat 241 cgacctcagg gacaggaagc agccttcgga gctgcggcgc atcgctggtc aggtgaagta

53 The Digital World Biological Systems: Electrical Systems:

54 Binary in History Yin-Yang Emblem G. Leibniz Pa Kua: Eight Trigrams
( ) Pa Kua: Eight Trigrams Binary exists for thousand of years in ancient Chinese history: yin-yang trigrams hexagrams G. Leibniz, 1679: formal development of the system of binary arithmetic

55 Signal, Signals, Signals
Continuous-Amplitude Discrete-Amplitude Continuous -Time (Space) Local telephone, cassette-tape recording,photograph telegraph Discrete Switched capacitor filter, speech storage chip, half-tone photography CD, DVD, cellular phones, digital camera & camcorder t x(t) t x(t) n x[n] n x[n]

56 Why Digital? Robust (less susceptible to noise) Simple
(deals with 0s & 1s)

57 Entering and Exiting the Digital World…

58 Entering and Exiting the Digital World… (cont’d)

59 Sampling ^ x(t) t x(t) t t x(t) ^ t x(t)
Increases the sampling rate and the amplitude resolution by a factor of 2 t x(t) ^ t x(t)

60 Sampling (cont’d) 300Hz 700Hz Sampling rate: 1000Hz 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 700Hz 300Hz Sampling rate: 1000Hz

61 Sampling (cont’d) Aliasing 700Hz Sampling rate increases to: 1400Hz
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

62 Sampling & Aliasing in Digital Images

63 Example: Digital Audio
processing or storage of digital signal (e.g., MP3)

64 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.

65 Measure amplitude at each tick of sample clock
Digital Quantization 3-bit quantization: use 3 bits to represent values 0,1,…7 1 2 3 4 5 6 7 Amplitude Measure amplitude at each tick of sample clock Time

66 Decimal-Binary Conversion
Quotient Remainder Divide the decimal number repeatedly until the quotient is zero. The remainders in reverse order give the number’s equivalent binary form 343/2 171 1 171/2 85 85/2 42 42/2 21 21/2 10 10/2 5 5/2 2 2/2 1/2 = 10 2 1 x x x x x 2 + 0 x x x x 2 = 343 8 7 6 5 4 3 2 1

67 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: 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

68 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 1, 2, 4, 8 bits/pixel 512x512, 256x256, 128x128 Positive, negative 64x64, 8 bit, 4 kB Lower resolution

69 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!

70 Digital Technology: DVD
Specification CD DVD Track Pitch 1600 nm 740 nm Min. Pit Length 830 nm 400/440 nm Storage Capacity 780 MB GB

71 Binary Logic - Logic Gates

72 Binary Arithmetic - Addition
Simple observation Addition Binary Decimal 0+0=0 0+1=1 1+0=1 1+1=10 1+1=2

73 Binary Arithmetic - Addition (cont’d)
Truth Table of Half-Adder Inputs Outputs A B Sum Carry 1 A B Sum Carry XOR AND What about n-bit inputs?

74 Principle of 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 1 1 1 1 1 carry 11 carry 108 + + MSB LSB 93 1 1 1 1 201 Binary Addition Decimal Addition

75 Binary Arithmetic - Addition the Full Adder
Inputs Outputs 1 We need to add three bits (A, B, and Carry), not two as in the half-adder This is called a full adder Carry-out Carry-in FA Sum

76 Binary Arithmetic - the N-bit Full Adder
S7 Co S8 A6 B6 S6 A5 B5 S5 A4 B4 S4 A3 B3 S3 A2 B2 S2 A1 B1 S1 Ci A0 B0 S0 first carry in, set to 0 here last carry out, overflow bit 8-bit Full Adder CKT = MATH (= $$$$$)

77 The Systems Approach (divide and conquer)

78 System - An external view
(Perform Function) Inputs Outputs System: A collection of interacting elements that form an integrated whole

79 Digital Hardware Building Block Hierarchy
Digital system (1) Circuit board (1-4) Chip (5-100) Logic gate (1k-500k) Transistor (1M-10M)

80 PC Motherboard Level Disk & USB interfaces Processor Memory
I/O bus slots Graphics Processor chip is hidden under the heat sink DRAM memories are on DIMMS (dual in-line memory modules)

81 Chip Level (Pentium 4 Processor)

82 Logic Gate Level NAND Gate Chip

83 Transistor Level Cross-section Layout
M1 word line Diffused bit line Polysilicon gate plate Capacitor Metal word line Poly SiO 2 Field Oxide n + Inversion layer induced by plate bias Cross-section Layout Uses Polysilicon-Diffusion Capacitance

84 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…

85 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 User-friendly software package for popular applications Word processors, & web browser, games… MOV 520 R0 ADD R0 R1 UNIX: ls –l rm *.* DOS: dir del *.* C++: x++ Fortran: x=x+1 Word Explorer Sims

86 Communication CKTs (Sense/React) React

87 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)

88 Cell Phones: Inside front back LCD & keypad microprocessor
flash memory speaker, microphone

89 Cell Phone System

90 Sound Fundamentals 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

91 Harmonics in Music Signals
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

92 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 Period: second (unit of time) Frequency: 1/sec or hertz [Hz] Phase: radians

93 Music Signals: Piano

94 Frequency Spectrum - Audio
Human Auditory System 20Hz-20kHz f (Hz) 10k 20k FM Radio Signals 100Hz-12kHz f (Hz) 10k 20k AM Radio Signals 100Hz-5kHz f (Hz) 10k 20k Telephone Speech 300Hz-3.5kHz f (Hz) 10k 20k

95 Frequency Spectrum - Music Signals

96 Transmitting & Receiving Information via Electromagnetic
Aeronautical comm MHz Maritime comm MHz VHF wireless, TV MHz Cellular phones 900, 1800, 2400 MHz Detection of buried land mines ( MHz) Microwave imaging of tumors MHz Radio astronomy 1413 MHz Microwave ovens 2400 MHz Bluetooth wireless Global position sat 1600, 1200 MHz Airport appr. radar 2700 MHz Satellite weather 12 GHz Satellite TV 14 GHz Satellite comm GHz Adv. environ. radars 37, 98, 220 GHz Large size devices Small bandwidth Small antenna gain Large penetration Small resolution Small size devices Large Bandwidth Large antenna gain Small penetration Large resolution c : speed of light f : frequency

97 Modulation

98 Modulation (cont’d) Modulation Pulse modulation Amplitude modulation
Using higher-frequency sinusoids to carry signals More efficient transmission & allow multi-user sharing Pulse modulation Amplitude modulation Frequency modulation Morse code, infrared remote control… AM radio stations, video part of TV signals… FM radio stations, Cell phones, cordless phones…

99 Radio Frequency Systems
An advanced RF /microwave system DSP/ Processor A/D waveguide T/R switch PA Mixer VCO Antenna LO LNA Power Supply

100 Modem Transmission 1 1 Transmit Receive frequency 1 1
Frequency-shift keying (FSK) Uses analog sinusoids of different frequencies to carry digital signals 1 1 Transmit Receive frequency 300 1070 1270 2025 2225 3300 1 1

101 Cell Phones Motorola Razr BlackBerry Frst cell phone 1973 DynaTAC 1983
Nokia N96 Sony Ericsson Xperia X1 Apple iPhone Google G1

102 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 Telephone Switching Office (MTSO) Each carrier: 832 radio frequencies Duplex system: 395 voice channels & 42 control channels Each cell: 56 voice channels

103 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 hand-off switching between cells based on signal strengths Everything happens within seconds or even less!

104 Switching, RF and Power Electronics
Cell Phone Tower Antenna Array Switching, RF and Power Electronics

105 What Next? Connect & collaborate with UMass Amherst ECE faculty
Teacher development grants Summer research experience for teachers Recommend exceptional high-school juniors/seniors summer research at UMass. Invite UMass Profs to High-school student seminars. M5 Open house for students and Teachers. Spread the word to students & colleagues. Participate on upcoming ECE SESS(more in-depth). Marinos N. Vouvakis

106 Disclaimer Some materials (drawings, figures, text) presented in these slides was obtained from the following web resources:


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