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Pri rinciples nciples of of Com ommunications munications EC ECS S 332 32 Dr. Prapun Suksompong prapun@siit.tu.ac.th Introduction Office Hours: BKD 3601-7 Monday 14:40-16:00 Friday 14:00-16:00 1

Course Organization  Course Website: http://www2.siit.tu.ac.th/prapun/ecs332/  Lectures:  Wednesday 09:00-10:20 BKD 3206  Friday 10:40-12:00 BKD 3206  Textbook: Communication Systems: An Introduction to Signals and Noise in Electrical Communication  By A. Bruce Carlson and Paul B. Crilly  5th International edition  Call No. TK5102.5 C3 2010  ISBN: 978-007-126332-0 2

Pri rinciples nciples of of Com ommunications munications EC ECS S 332 32 Dr. Prapun Suksompong prapun@siit.tu.ac.th 1. Intro to comm. system Office Hours: BKD 3601-7 Monday 14:40-16:00 Friday 14:00-16:00 1

“The fundamental problem of communication is that of reproducing at one point either exactly or approximately a message selected at another point.” Shannon, Claude. A Mathematical Theory Of Communication. (1948) 3

C. E. Shannon (1916-2001)  1938 MIT master's thesis: A Symbolic Analysis of Relay and Switching Circuits  Insight: The binary nature of Boolean logic was analogous to the ones and zeros used by digital circuits .  The thesis became the foundation of practical digital circuit design.  The first known use of the term bit to refer to a “ binary digit .”  Possibly the most important, and also the most famous, master's thesis of the century.  It was simple, elegant, and important . 4

C. E. Shannon ( Con’t )  1948: A Mathematical Theory of Communication  Bell System Technical Journal, vol. 27, pp. 379-423, July- October, 1948.  September 1949: Book published. Include a new section by Warren Weaver that  Invent Information Theory : applied Shannon's theory to Simultaneously founded the human communication. subject, introduced all of the  Create the architecture and major concepts, and stated and concepts governing digital proved all the fundamental communication. theorems. 5

A Mathematical Theory of Communication  Link posted in the “references” section of the website. 6 [An offprint from the Bell System Technical Journal]

Shannon - Father of the Info. Age 7 [http://www.youtube.com/watch?v=z2Whj_nL-x8]

Claude E. Shannon Award Claude E. Shannon (1972) Elwyn R. Berlekamp (1993) Sergio Verdu (2007) Aaron D. Wyner (1994) Robert M. Gray (2008) David S. Slepian (1974) G. David Forney, Jr. (1995) Jorma Rissanen (2009) Robert M. Fano (1976) Imre Csiszár (1996) Te Sun Han (2010) Peter Elias (1977) Jacob Ziv (1997) Shlomo Shamai (Shitz) (2011) Mark S. Pinsker (1978) Neil J. A. Sloane (1998) Jacob Wolfowitz (1979) Tadao Kasami (1999) W . Wesley Peterson (1981) Thomas Kailath (2000) Irving S. Reed (1982) Jack Keil Wolf (2001) Robert G. Gallager (1983) Toby Berger (2002) Solomon W . Golomb (1985) William L. Root (1986) Lloyd R. Welch (2003) James L. Massey (1988) Robert J. McEliece (2004) Thomas M. Cover (1990) Richard Blahut (2005) Andrew J. Viterbi (1991) Rudolf Ahlswede (2006) 8

Information Theory The science of information theory tackles the following questions [Berger] What is information, i.e., how do we measure it 1. quantitatively? What factors limit the reliability with which information 2. generated at one point can be reproduced at another, and what are the resulting limits? How should communication systems be designed in order 3. to achieve or at least to approach these limits? 9

Basic elements of communication  Information source : produce a message  Transmitter : operate on the message to create a signal which can be sent through a channel Received Transmitted Message Message Signal Signal Information Channel Destination Receiver Transmitter Source Noise Source 10

Basic elements (2)  Channel : the medium over which the signal, carrying the information that composes the message, is sent  Receiver : transform the signal back into the message intended for delivery Received Transmitted Message Message Signal Signal Information Channel Destination Receiver Transmitter Source Noise Source 11

Basic elements (3)  Destination : a person or a machine, for whom or which the message is intended Received Transmitted Message Message Signal Signal Information Channel Destination Receiver Transmitter Source Noise Source 12

Digital Communication Binary data stream (sequence of data) without meaning (from channel viewpoint). Waveform  sequence  symbols  bits Take the bits from one place to another. Source Channel Input 010100 Encoder Encoder Binary Interface Know the probabilistic + noise & interference structure of the input Channel source. Output Source Channel 010100 Decoder Decoder 13 This is the major layering of all digital communication systems.

References  A Brief History of Communications: IEEE Communications Society - a fifty-year foundation for the future  ประวัติย่อ "การสื่อสารโลก": ห้าสิบปีชมรมไฟฟ้า สื่อสาร — รากฐานสู่อนาคต  Thai Telecommunications Encyclopedia ( สารานุกรม โทรคมนาคมไทย)  Links posted in the “references” section of the website. 14

Pri Principles of Comm nciples of Communi unications cations EC ECS 332 S 332 Dr. Prapun Suksompong prapun@siit.tu.ac.th 2. Frequency-Domain Analysis Office Hours: BKD 3601-7 Monday 14:40-16:00 Friday 14:00-16:00 1

The Most Beautiful Equation 2

7 Equations that changed the world … and still rule everyday life 3

4

What’s wrong with this picture? 5

The cochlea has sometimes been described as a biological Fourier analyzer . Fourier Transform in Auditory System Approximate best frequencies of various places along the basilar membrane, in hertz. [Schnupp, Nelken, and King, 2010, Fig 2.2] Human Audiogram (Audibility Curve) [Schnupp, Nelken, and King, 2010, Fig 2.1] Schematic showing the cochlea unrolled, in cross-section. 6 [Schnupp, Nelken, and King, 2010, Fig 2.2] [http://psyc254.uconn.edu/Lecture18/]

Spectrum of Digital Data (1/4)     A 1, T 1 1          c t A 1 t 0, T     0.8 C f 0.6 A 0.4 0.2 t T 0 -5 -4 -3 -2 -1 0 1 2 3 4 5 f [Hz] m = [-1,-1,1,-1,-1,1,1,-1,-1,-1,1,-1,-1,1,-1,1,1,-1,-1,-1,-1,1,-1,-1,-1,-1,-1,1,-1,1]   s t A Can you sketch the spectrum of s ( t )? t -A 7

Spectrum of Digital Data (2/4)     A 1, T 1 1          c t A 1 t 0, T     0.8 C f This is also the spectrum of 0.6   A  c t kT for any . k 0.4 0.2 t T 0 -5 -4 -3 -2 -1 0 1 2 3 4 5 f [Hz] m = [-1,-1,1,-1,-1,1,1,-1,-1,-1,1,-1,-1,1,-1,1,1,-1,-1,-1,-1,1,-1,-1,-1,-1,-1,1,-1,1]   s t  A n 1        s t m c t kT k t  k 0 -A 8

Spectrum of Digital Data (3/4)     A 1, T 1 1          c t A 1 t 0, T     0.8 C f This is also the spectrum of 0.6   A  c t kT for any . k 0.4 0.2 t T 0 -5 -4 -3 -2 -1 0 1 2 3 4 5 f [Hz] m = [-1,-1,1,-1,-1,1,1,-1,-1,-1,1,-1,-1,1,-1,1,1,-1,-1,-1,-1,1,-1,-1,-1,-1,-1,1,-1,1]   s t  A n 1        s t m c t kT k t  k 0  -A n 1           j 2 fkT S f C f m e k  0 k 9

Spectrum of Digital Data (4/4)     A 1, T 1 1          c t A 1 t 0, T     0.8 C f This is also the spectrum of 0.6   A  c t kT for any . k 0.4 0.2 t T 0 -5 -4 -3 -2 -1 0 1 2 3 4 5 f [Hz] m = [-1,-1,1,-1,-1,1,1,-1,-1,-1,1,-1,-1,1,-1,1,1,-1,-1,-1,-1,1,-1,-1,-1,-1,-1,1,-1,1] 10   s t   8 A S f 6 t 4 -A 2 0 -5 -4 -3 -2 -1 0 1 2 3 4 5 f [Hz]   n 1 n 1                  j 2 fkT s t m c t kT S f C f m e k k 10   k 0 k 0

Example: Convolution 11

Important Formulas (Will be provided on the midterm)      j e cos j sin     2 2cos x 1 cos 2 x     2 2sin x 1 cos 2 x          j 2 ft G f g t e dt   1 1                  j j cos 2 f t f f e f f e c c c 2 2        j 2 ft g t t e G f 0 0       j 2 f t e g t G f f 0 0 1 1             m t cos 2 f t M f f M f f c c c 2 2 12

Pri Principles of Comm nciples of Communi unications cations EC ECS 332 S 332 Dr. Prapun Suksompong prapun@siit.tu.ac.th 3. Modulation Office Hours: BKD 3601-7 Monday 14:40-16:00 Friday 14:00-16:00 1