Fundamentals of Digital Communication

Size: px
Start display at page:

Download "Fundamentals of Digital Communication"

Transcription

1 Fundamentals of Digital Communication Network Infrastructures A.A. 2017/18 Digital communication system Analog Digital Input Signal Analog/ Digital Low Pass Filter Sampler Quantizer Source Encoder Channel Encoder Multiplexer Carrier Twisted Pair Co-axial Cable Optical Fiber Wireless Space To Channel From Channel Modulator De- Modulator Pulse Shaping Filters Receiver Filter Line Encoder Detector Carrier Recovery Symbol timing Recovery Signal at the user end Digital-to-Analog Converter Channel Decoder De- Multiplexer Analog Digital 2 1

2 Digital Modulation cost effective because of advances in digital technology (VHDL, DSP, FPGA ) advantages/disadvantages vs analog - better noise immunity - robustness to channel impairments - ability to multiplex information - error control: detect & correct corrupt bits - able to encrypt data - flexible software modulation & demodulation - requires complex signal conditioning modulating signal (message) represented as pulses n bits represented by m finite states n = log 2 m 3 Factors in Digital Modulation efficiency: low BER at low SNR channel: multipath & fading conditions minimize bandwidth required cost-effective & easy implementation Performance Measures for Modulation Schemes (i) p = power efficiency (ii) B = bandwidth efficiency 4 2

3 (i) Power Efficiency, p Ability to preserve signal fidelity at low power increasing signal power increases noise immunity specifics depend on modulation technique measures trade-off between fidelity & signal power p often expressed as ratio of E b to N 0 at receiver input to achieve specified BER p =E b / N 0 E b = bit energy N 0 = noise power spectral density 5 (ii) Bandwidth Efficiency, B Ability to accommodate data in limited bandwidth increasing data rate requires increased bandwidth direct relationship to system capacity measured in terms of bit rate, R b & RF bandwidth, B B =R b /B 6.36 Fundamental Upper Bound on achievable Bit Rate per given Bandwidth (aka Shannon Bound) Bmax = C/B S Bmax = log N C = maximum channel capacity (bps) 6 3

4 typically there is a tradeoff between B & p e.g addition of error control codes increases p and decreases B - increases bandwidth for given data rate - reduces required received power for specified BER use of M-ary keying increases B and decreases p - decreases bandwidth for given data rate - requires increased receive power for specified BER 7 Additional factors in digital modulation cost & complexity simplicity is better channel impairments (Rayleigh, Ricean fading) - multipath dispersion - interference detection sensitivity to timing jitter time varying channel typically system is simulated & all factors are analyzed prior to selection of methods and specification of parameters 8 4

5 Analog vs. Digital Analog signals Value varies continuously Digital signals Value limited to a finite set x(t) x(t) t Binary signals Has at most 2 values Used to represent bit values Bit time T needed to send 1 bit Data rate R=1/T bits per second x(t) 1 0 T t t 9 Performance Metrics In analog communications we want, mˆ ( t) m( t) Digital communication systems: Data rate (R bps) Limited by Channel Capacity Probability of error Without noise, there are no bit errors Bit Error Rate (BER): Number of bit errors that occur for a given number of bits transmitted. What s BER if P e =10-6 and 10 7 bits are transmitted? 10 5

6 Analog versus Digital Harder to separate noise from an analog signal than from a digital signal If there is too much noise cannot discern a high voltage from a low voltage 11 Analog versus Digital Regenerator receiver Original pulse Regenerated pulse Propagation distance Different kinds of digital signal are treated identically. Data Voice Media A bit is a bit! 12 6

7 Analog versus Digital Stability of components: Analog hardware change due to component aging, heat, etc. Flexibility: Perform encryption Compression Error correction/detection Reliable reproduction 13 Bandwidth of signal Baseband versus bandpass: Baseband signal Local oscillator Bandpass signal Bandwidth dilemma: Bandlimited signals are not realizable! Realizable signals have infinite bandwidth! 14 7

8 Different definition of bandwidth: a) Half-power bandwidth b) Noise equivalent bandwidth c) Null-to-null bandwidth d) Fractional power containment bandwidth e) Bounded power spectral density f) Absolute bandwidth (a) (b) (c) (d) (e)50db 15 Sampling Time domain Frequency domain x s X s x(t) X ( f ) ( t) x ( t) x( t) ( f ) X ( f ) X ( f ) (t) x ( f ) X (t) x s ( f ) X s 16 8

9 Aliasing effect LP filter Nyquist rate aliasing 17 Sampling theorem Analog signal Sampling process Pulse amplitude modulated (PAM) signal Sampling theorem: A bandlimited signal with no spectral components beyond, can be uniquely determined by values sampled at uniform intervals of The sampling rate, is called Nyquist rate. 18 9

10 Quantization Amplitude quantizing: Mapping samples of a continuous amplitude waveform to a finite set of amplitudes. Out In Average quantization noise power Quantized values Signal peak power Signal power to average quantization noise power 19 Encoding (PCM) Pulse code modulation (PCM): Encoding the quantized signals into a digital word (PCM word or codeword). Each quantized sample is digitally encoded into an l bits codeword where L in the number of quantization levels and 20 10

11 amplitude x(t) Quantization example Quant. levels boundaries PCM codeword xq(nts): quantized values x(nts): sampled values Ts: sampling time t PCM sequence 21 Quantization error Quantizing error: The difference between the input and output of a quantizer e( t) xˆ( t) x( t) Process of quantizing noise Qauntizer y q(x) Model of quantizing noise AGC x (t) xˆ ( t) x x (t) xˆ ( t) e(t) + e( t) xˆ( t) x( t) 22 11

12 Quantization error Quantizing error: Granular or linear errors happen for inputs within the dynamic range of quantizer Saturation errors happen for inputs outside the dynamic range of quantizer Saturation errors are larger than linear errors Saturation errors can be avoided by proper tuning of AGC Quantization noise variance: 2 q E {[ x q( x)] } e ( x) p( x) dx Lin Sat 2 2 ql Lin 2 p( xl ) ql Uniform q. 12 L / 2 1 l0 2 Lin 2 q Uniform and non-uniform quant. Uniform (linear) quantizing: No assumption about amplitude statistics and correlation properties of the input. Not using the user-related specifications Robust to small changes in input statistic by not finely tuned to a specific set of input parameters Simply implemented Application of linear quantizer: Signal processing, graphic and display applications, process control applications Non-uniform quantizing: Using the input statistics to tune quantizer parameters Larger SNR than uniform quantizing with same number of levels Non-uniform intervals in the dynamic range with same quantization noise variance Application of non-uniform quantizer: Commonly used for speech 24 12

13 Non-uniform quantization It is done by uniformly quantizing the compressed signal. At the receiver, an inverse compression characteristic, called expansion is employed to avoid signal distortion. compression+expansion companding y C(x) x xˆ (t) y(t) y ˆ( t ) xˆ ( t) Compress x Transmitter Quantize Channel Expand Receiver ŷ 25 Pulse Code Modulation (continued) Binary values are later converted to an analog signal Waveform similar to original results 26 13

14 Pulse Code Modulation (continued) The more snapshots taken in the same amount of time, or the more quantization levels, the better the resolution 27 Pulse Code Modulation (continued) Because the human voice has a fairly narrow bandwidth Telephone systems digitize voice into either 128 levels or 256 levels Called quantization levels If 128 levels, then each sample is 7 bits (2 ^ 7 = 128) If 256 levels, then each sample is 8 bits (2 ^ 8 = 256) 28 14

15 Pulse Code Modulation (continued) How fast do you have to sample an input source to get a fairly accurate representation? Nyquist says 2 times the bandwidth Thus, if you want to digitize voice (4000 Hz), you need to sample at 8000 samples per second 29 Delta Modulation An analog waveform is tracked using a binary 1 to represent a rise in voltage and a 0 to represent a drop 30 15

16 Source Coding To eliminate redundancy Huffman Coding Shannon-Fano Coding To maximize information rate in a transmission What is Information Rate? Information per bit Entropy 31 Channel Coding Error Control Coding To reduce the impact of channel errors by controlled introduction of redundancy Decrease in effective data rate Increased coding gain Forward Error Correcting Codes Linear Block Codes Convolutional Codes ARQ methods 32 16

17 Line Coding Formats (Converting Data into Signals) Numerous techniques NRZ-L NRZ-I Manchester Differential Manchester Bipolar AMI 33 Converting Data into Signals (continued) 34 17

18 Pulse Shaping Filters Bandlimiting signals in frequency domain spreads signal in time domain Inter-Symbol Interference ISI Nyquist Criterian to overcome ISI Pulse Shaping Filters Raised Cosine Filters Gaussian shaping filters 35 Consider: sin( t / Ts ) h eff (t) = 6.44 t / T s Assume that for n > 0 h eff (nt s ) = x NYQ (t) sin( t / T s ) t / T s -6T -4T -2T 0 2T 4T 6T h eff (nt s ) = 0 18

19 Transfer function of Nyquist Pulse Shaping Filter H NYQ (f) 1 1 2T 1 1 2T 2T 1 2T 1 2T 1 2T scaling factor, 0 1 = 0 Guassian filter has narrow absolute bandwidth not as narrow as RC filter sharp cut-off frequency & low overshoot smooth transfer function & no zero crossings good design choice when cost & power efficiency are most important BER from ISI is less critical issue Nyquist (RRC) filters have zero crossings at adjacent symbol peaks truncated transfer function assume flat channel response (equalized) 19

20 Baseband RC Filter impulse response plotted for 0 1 Baseband Gaussian Filter impulse response plotted for different B 3dB T s = 0 = 0.5 = 1 h RC (t) 1/T s h G (t) = 0.5 = 0.75 = 1.0 = 2.0-4T -3T -2T -T 0 T 2T 3T 4T 3 T s 2 T s 2 T s 2 3 s T 2 t 39 What is modulation Modulation is the process of encoding information from a message source in a manner suitable for transmission It involves translating a baseband message signal to a bandpass signal at frequencies that are very high compared to the baseband frequency. Baseband signal is called modulating signal Bandpass signal is called modulated signal 40 20

21 Modulation Techniques Modulation can be done by varying the Amplitude Phase, or Frequency of a high frequency carrier in accordance with the amplitude of the message signal. Demodulation is the inverse operation: extracting the baseband message from the carrier so that it may be processed at the receiver. 41 Fundamentals of Signals Amplitude Height of the wave above or below a given reference point Frequency Number of times a signal makes complete cycle within a given time frame Spectrum - Range of frequencies that a signal spans from minimum to maximum Bandwidth - The absolute value of the difference between the lowest and highest frequencies of a signal For example, voice spectrum Hz 42 21

22 Fundamentals of Signals (continued) Phase Position of the waveform relative to a given moment of time or relative to time zero A change in phase can be any number of angles between 0 and 360 degrees Phase changes often occur on common angles, such as 45, 90, 135, etc. 43 Where do you need modulation? Orthogonal Frequency Division Multiplexing ADSL 44 22

23 Formatting and transmission of baseband signal Digital info. source Textual info. Analog info. Sample Format Quantize Encode Pulse modulate Transmit sink Analog info. Textual info. Low-pass filter Format Decode Bit stream Pulse waveforms Demodulate/ Detect Channel Receive Digital info. 45 Modulation -Transmitting Digital Data with Analog Signals Three basic techniques: Amplitude shift keying Frequency shift keying Phase shift keying 46 23

24 Amplitude Shift Keying One amplitude encodes a 0 while another amplitude encodes a 1 (a form of amplitude modulation) 47 Amplitude Shift Keying (continued) Some systems use multiple amplitudes 48 24

25 Amplitude Shift Keying (continued) Multiple Signal Levels Why use multiple signal levels? We can represent two levels with a single bit, 0 or 1 We can represent four levels with two bits: 00, 01, 10, 11 We can represent eight levels with three bits: 000, 001, 010, 011, 100, 101, 110, 111 Note that the number of levels is always a power of 2 49 Frequency Shift Keying One frequency encodes a 0 while another frequency encodes a 1 (a form of frequency modulation) 50 25

26 Phase Shift Keying One phase change encodes a 0 while another phase change encodes a 1 (a form of phase modulation) 51 Goal of Advanced Modulation and Coding Techniques Modulation is difficult task in hostile channels like the mobile radio channels Small-scale fading and multi-path conditions. The goal of a modulation scheme is: To transport the message signal through the radio channel with best possible quality. To occupy least amount of radio (RF) spectrum

27 Multipath Propagation LOS pulses multipath pulses signal at sender signal at receiver power long term fading short term fading t 53 Wireless channel Effective channel depends on both physical environment and bandwidth! 54 27

28 Channel Classification Flat Fading Channel Slow Fading Channel Channel Coherence bandwidth >> Signal bandwidth Channel Coherence time >> Symbol duration Frequency Selective Fading Channel Fast Fading Channel Channel Coherence bandwidth << Signal bandwidth Channel Coherence time >> Symbol duration 55 Phase Shift Keying (continued) Quadrature Phase Shift Keying Four different phase angles are used: 45 degrees 135 degrees 225 degrees 315 degrees 56 28

29 Phase Shift Keying (continued) 57 Phase Shift Keying (continued) Quadrature Amplitude Modulation 12 different phases are combined with two different amplitudes Since only 4 phase angles have 2 different amplitudes, there are a total of 16 combinations. With 16 signal combinations, each baud equals 4 bits of information (2 ^ 4 = 16) 58 29

30 Phase Shift Keying (continued) 59 Spread Spectrum Technology A secure encoding technique that uses multiple frequencies or codes to transmit data Two basic spread spectrum technologies: Frequency hopping spread spectrum Direct sequence spread spectrum 60 30

31 Spread Spectrum Technology (continued) 61 Spread Spectrum Technology (continued) Direct Sequence Spread Spectrum This technology replaces each binary 0 and binary 1 with a unique pattern, or sequence, of 1s and 0s For example, one transmitter may transmit the sequence for each binary 1, and for each binary 0 Another transmitter may transmit the sequence for each binary 1, and for each binary

32 OFDM OFDM = Orthogonal FDM Carrier centers are put on orthogonal frequencies ORTHOGONALITY - The peak of each signal coincides with trough of other signals Subcarriers are spaced by 1/Ts 63 Thank you 64 32

EEE 309 Communication Theory

EEE 309 Communication Theory EEE 309 Communication Theory Semester: January 2016 Dr. Md. Farhad Hossain Associate Professor Department of EEE, BUET Email: mfarhadhossain@eee.buet.ac.bd Office: ECE 331, ECE Building Part 05 Pulse Code

More information

EEE 309 Communication Theory

EEE 309 Communication Theory EEE 309 Communication Theory Semester: January 2017 Dr. Md. Farhad Hossain Associate Professor Department of EEE, BUET Email: mfarhadhossain@eee.buet.ac.bd Office: ECE 331, ECE Building Types of Modulation

More information

Downloaded from 1

Downloaded from  1 VII SEMESTER FINAL EXAMINATION-2004 Attempt ALL questions. Q. [1] How does Digital communication System differ from Analog systems? Draw functional block diagram of DCS and explain the significance of

More information

EITF25 Internet Techniques and Applications L2: Physical layer. Stefan Höst

EITF25 Internet Techniques and Applications L2: Physical layer. Stefan Höst EITF25 Internet Techniques and Applications L2: Physical layer Stefan Höst Data vs signal Data: Static representation of information For storage Signal: Dynamic representation of information For transmission

More information

Wireless Communication: Concepts, Techniques, and Models. Hongwei Zhang

Wireless Communication: Concepts, Techniques, and Models. Hongwei Zhang Wireless Communication: Concepts, Techniques, and Models Hongwei Zhang http://www.cs.wayne.edu/~hzhang Outline Digital communication over radio channels Channel capacity MIMO: diversity and parallel channels

More information

Department of Electronics and Communication Engineering 1

Department of Electronics and Communication Engineering 1 UNIT I SAMPLING AND QUANTIZATION Pulse Modulation 1. Explain in detail the generation of PWM and PPM signals (16) (M/J 2011) 2. Explain in detail the concept of PWM and PAM (16) (N/D 2012) 3. What is the

More information

EXPERIMENT WISE VIVA QUESTIONS

EXPERIMENT WISE VIVA QUESTIONS EXPERIMENT WISE VIVA QUESTIONS Pulse Code Modulation: 1. Draw the block diagram of basic digital communication system. How it is different from analog communication system. 2. What are the advantages of

More information

Chapter Two. Fundamentals of Data and Signals. Data Communications and Computer Networks: A Business User's Approach Seventh Edition

Chapter Two. Fundamentals of Data and Signals. Data Communications and Computer Networks: A Business User's Approach Seventh Edition Chapter Two Fundamentals of Data and Signals Data Communications and Computer Networks: A Business User's Approach Seventh Edition After reading this chapter, you should be able to: Distinguish between

More information

Basic Concepts in Data Transmission

Basic Concepts in Data Transmission Basic Concepts in Data Transmission EE450: Introduction to Computer Networks Professor A. Zahid A.Zahid-EE450 1 Data and Signals Data is an entity that convey information Analog Continuous values within

More information

Digital Communication (650533) CH 3 Pulse Modulation

Digital Communication (650533) CH 3 Pulse Modulation Philadelphia University/Faculty of Engineering Communication and Electronics Engineering Digital Communication (650533) CH 3 Pulse Modulation Instructor: Eng. Nada Khatib Website: http://www.philadelphia.edu.jo/academics/nkhatib/

More information

QUESTION BANK SUBJECT: DIGITAL COMMUNICATION (15EC61)

QUESTION BANK SUBJECT: DIGITAL COMMUNICATION (15EC61) QUESTION BANK SUBJECT: DIGITAL COMMUNICATION (15EC61) Module 1 1. Explain Digital communication system with a neat block diagram. 2. What are the differences between digital and analog communication systems?

More information

Revision of Wireless Channel

Revision of Wireless Channel Revision of Wireless Channel Quick recap system block diagram CODEC MODEM Wireless Channel Previous three lectures looked into wireless mobile channels To understand mobile communication technologies,

More information

QUESTION BANK EC 1351 DIGITAL COMMUNICATION YEAR / SEM : III / VI UNIT I- PULSE MODULATION PART-A (2 Marks) 1. What is the purpose of sample and hold

QUESTION BANK EC 1351 DIGITAL COMMUNICATION YEAR / SEM : III / VI UNIT I- PULSE MODULATION PART-A (2 Marks) 1. What is the purpose of sample and hold QUESTION BANK EC 1351 DIGITAL COMMUNICATION YEAR / SEM : III / VI UNIT I- PULSE MODULATION PART-A (2 Marks) 1. What is the purpose of sample and hold circuit 2. What is the difference between natural sampling

More information

CHAPTER 3 Syllabus (2006 scheme syllabus) Differential pulse code modulation DPCM transmitter

CHAPTER 3 Syllabus (2006 scheme syllabus) Differential pulse code modulation DPCM transmitter CHAPTER 3 Syllabus 1) DPCM 2) DM 3) Base band shaping for data tranmission 4) Discrete PAM signals 5) Power spectra of discrete PAM signal. 6) Applications (2006 scheme syllabus) Differential pulse code

More information

Communications I (ELCN 306)

Communications I (ELCN 306) Communications I (ELCN 306) c Samy S. Soliman Electronics and Electrical Communications Engineering Department Cairo University, Egypt Email: samy.soliman@cu.edu.eg Website: http://scholar.cu.edu.eg/samysoliman

More information

Detection and Estimation of Signals in Noise. Dr. Robert Schober Department of Electrical and Computer Engineering University of British Columbia

Detection and Estimation of Signals in Noise. Dr. Robert Schober Department of Electrical and Computer Engineering University of British Columbia Detection and Estimation of Signals in Noise Dr. Robert Schober Department of Electrical and Computer Engineering University of British Columbia Vancouver, August 24, 2010 2 Contents 1 Basic Elements

More information

Lecture 3 Concepts for the Data Communications and Computer Interconnection

Lecture 3 Concepts for the Data Communications and Computer Interconnection Lecture 3 Concepts for the Data Communications and Computer Interconnection Aim: overview of existing methods and techniques Terms used: -Data entities conveying meaning (of information) -Signals data

More information

Digital Communication System

Digital Communication System Digital Communication System Purpose: communicate information at required rate between geographically separated locations reliably (quality) Important point: rate, quality spectral bandwidth, power requirements

More information

UNIT-1. Basic signal processing operations in digital communication

UNIT-1. Basic signal processing operations in digital communication UNIT-1 Lecture-1 Basic signal processing operations in digital communication The three basic elements of every communication systems are Transmitter, Receiver and Channel. The Overall purpose of this system

More information

Time division multiplexing The block diagram for TDM is illustrated as shown in the figure

Time division multiplexing The block diagram for TDM is illustrated as shown in the figure CHAPTER 2 Syllabus: 1) Pulse amplitude modulation 2) TDM 3) Wave form coding techniques 4) PCM 5) Quantization noise and SNR 6) Robust quantization Pulse amplitude modulation In pulse amplitude modulation,

More information

Ș.l. dr. ing. Lucian-Florentin Bărbulescu

Ș.l. dr. ing. Lucian-Florentin Bărbulescu Ș.l. dr. ing. Lucian-Florentin Bărbulescu 1 Data: entities that convey meaning within a computer system Signals: are the electric or electromagnetic impulses used to encode and transmit data Characteristics

More information

Signal Encoding Techniques

Signal Encoding Techniques 2 Techniques ITS323: to Data Communications CSS331: Fundamentals of Data Communications Sirindhorn International Institute of Technology Thammasat University Prepared by Steven Gordon on 3 August 2015

More information

Lecture Fundamentals of Data and signals

Lecture Fundamentals of Data and signals IT-5301-3 Data Communications and Computer Networks Lecture 05-07 Fundamentals of Data and signals Lecture 05 - Roadmap Analog and Digital Data Analog Signals, Digital Signals Periodic and Aperiodic Signals

More information

Terminology (1) Chapter 3. Terminology (3) Terminology (2) Transmitter Receiver Medium. Data Transmission. Direct link. Point-to-point.

Terminology (1) Chapter 3. Terminology (3) Terminology (2) Transmitter Receiver Medium. Data Transmission. Direct link. Point-to-point. Terminology (1) Chapter 3 Data Transmission Transmitter Receiver Medium Guided medium e.g. twisted pair, optical fiber Unguided medium e.g. air, water, vacuum Spring 2012 03-1 Spring 2012 03-2 Terminology

More information

Pulse Code Modulation

Pulse Code Modulation Pulse Code Modulation Modulation is the process of varying one or more parameters of a carrier signal in accordance with the instantaneous values of the message signal. The message signal is the signal

More information

Chapter-1: Introduction

Chapter-1: Introduction Chapter-1: Introduction The purpose of a Communication System is to transport an information bearing signal from a source to a user destination via a communication channel. MODEL OF A COMMUNICATION SYSTEM

More information

Syllabus. osmania university UNIT - I UNIT - II UNIT - III CHAPTER - 1 : INTRODUCTION TO DIGITAL COMMUNICATION CHAPTER - 3 : INFORMATION THEORY

Syllabus. osmania university UNIT - I UNIT - II UNIT - III CHAPTER - 1 : INTRODUCTION TO DIGITAL COMMUNICATION CHAPTER - 3 : INFORMATION THEORY i Syllabus osmania university UNIT - I CHAPTER - 1 : INTRODUCTION TO Elements of Digital Communication System, Comparison of Digital and Analog Communication Systems. CHAPTER - 2 : DIGITAL TRANSMISSION

More information

PULSE CODE MODULATION (PCM)

PULSE CODE MODULATION (PCM) PULSE CODE MODULATION (PCM) 1. PCM quantization Techniques 2. PCM Transmission Bandwidth 3. PCM Coding Techniques 4. PCM Integrated Circuits 5. Advantages of PCM 6. Delta Modulation 7. Adaptive Delta Modulation

More information

UNIT TEST I Digital Communication

UNIT TEST I Digital Communication Time: 1 Hour Class: T.E. I & II Max. Marks: 30 Q.1) (a) A compact disc (CD) records audio signals digitally by using PCM. Assume the audio signal B.W. to be 15 khz. (I) Find Nyquist rate. (II) If the Nyquist

More information

ITM 1010 Computer and Communication Technologies

ITM 1010 Computer and Communication Technologies ITM 1010 Computer and Communication Technologies Lecture #14 Part II Introduction to Communication Technologies: Digital Signals: Digital modulation, channel sharing 2003 香港中文大學, 電子工程學系 (Prof. H.K.Tsang)

More information

Voice Transmission --Basic Concepts--

Voice Transmission --Basic Concepts-- Voice Transmission --Basic Concepts-- Voice---is analog in character and moves in the form of waves. 3-important wave-characteristics: Amplitude Frequency Phase Telephone Handset (has 2-parts) 2 1. Transmitter

More information

Outline / Wireless Networks and Applications Lecture 3: Physical Layer Signals, Modulation, Multiplexing. Cartoon View 1 A Wave of Energy

Outline / Wireless Networks and Applications Lecture 3: Physical Layer Signals, Modulation, Multiplexing. Cartoon View 1 A Wave of Energy Outline 18-452/18-750 Wireless Networks and Applications Lecture 3: Physical Layer Signals, Modulation, Multiplexing Peter Steenkiste Carnegie Mellon University Spring Semester 2017 http://www.cs.cmu.edu/~prs/wirelesss17/

More information

Sixth Semester B.E. Degree Examination, May/June 2010 Digital Communication Note: Answer any FIVEfull questions, selecting at least TWO questionsfrom each part. PART-A a. With a block diagram, explain

More information

University of Swaziland Faculty of Science Department of Electrical and Electronic Engineering Main Examination 2016

University of Swaziland Faculty of Science Department of Electrical and Electronic Engineering Main Examination 2016 University of Swaziland Faculty of Science Department of Electrical and Electronic Engineering Main Examination 2016 Title of Paper Course Number Time Allowed Instructions Digital Communication Systems

More information

Lecture 13. Introduction to OFDM

Lecture 13. Introduction to OFDM Lecture 13 Introduction to OFDM Ref: About-OFDM.pdf Orthogonal frequency division multiplexing (OFDM) is well-known to be effective against multipath distortion. It is a multicarrier communication scheme,

More information

SEN366 Computer Networks

SEN366 Computer Networks SEN366 Computer Networks Prof. Dr. Hasan Hüseyin BALIK (5 th Week) 5. Signal Encoding Techniques 5.Outline An overview of the basic methods of encoding digital data into a digital signal An overview of

More information

ETSF15 Physical layer communication. Stefan Höst

ETSF15 Physical layer communication. Stefan Höst ETSF15 Physical layer communication Stefan Höst Physical layer Analog vs digital (Previous lecture) Transmission media Modulation Represent digital data in a continuous world Disturbances, Noise and distortion

More information

Digital Communication System

Digital Communication System Digital Communication System Purpose: communicate information at certain rate between geographically separated locations reliably (quality) Important point: rate, quality spectral bandwidth requirement

More information

COMMUNICATION SYSTEMS

COMMUNICATION SYSTEMS COMMUNICATION SYSTEMS 4TH EDITION Simon Hayhin McMaster University JOHN WILEY & SONS, INC. Ш.! [ BACKGROUND AND PREVIEW 1. The Communication Process 1 2. Primary Communication Resources 3 3. Sources of

More information

MSK has three important properties. However, the PSD of the MSK only drops by 10log 10 9 = 9.54 db below its midband value at ft b = 0.

MSK has three important properties. However, the PSD of the MSK only drops by 10log 10 9 = 9.54 db below its midband value at ft b = 0. Gaussian MSK MSK has three important properties Constant envelope (why?) Relatively narrow bandwidth Coherent detection performance equivalent to that of QPSK However, the PSD of the MSK only drops by

More information

Chapter 2: Fundamentals of Data and Signals

Chapter 2: Fundamentals of Data and Signals Chapter 2: Fundamentals of Data and Signals TRUE/FALSE 1. The terms data and signal mean the same thing. F PTS: 1 REF: 30 2. By convention, the minimum and maximum values of analog data and signals are

More information

Digital Modulation Schemes

Digital Modulation Schemes Digital Modulation Schemes 1. In binary data transmission DPSK is preferred to PSK because (a) a coherent carrier is not required to be generated at the receiver (b) for a given energy per bit, the probability

More information

EC 554 Data Communications

EC 554 Data Communications EC 554 Data Communications Mohamed Khedr http://webmail. webmail.aast.edu/~khedraast.edu/~khedr Syllabus Tentatively Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 Week 10 Week 11 Week

More information

EC 2301 Digital communication Question bank

EC 2301 Digital communication Question bank EC 2301 Digital communication Question bank UNIT I Digital communication system 2 marks 1.Draw block diagram of digital communication system. Information source and input transducer formatter Source encoder

More information

QUESTION BANK. SUBJECT CODE / Name: EC2301 DIGITAL COMMUNICATION UNIT 2

QUESTION BANK. SUBJECT CODE / Name: EC2301 DIGITAL COMMUNICATION UNIT 2 QUESTION BANK DEPARTMENT: ECE SEMESTER: V SUBJECT CODE / Name: EC2301 DIGITAL COMMUNICATION UNIT 2 BASEBAND FORMATTING TECHNIQUES 1. Why prefilterring done before sampling [AUC NOV/DEC 2010] The signal

More information

Data Communication. Chapter 3 Data Transmission

Data Communication. Chapter 3 Data Transmission Data Communication Chapter 3 Data Transmission ١ Terminology (1) Transmitter Receiver Medium Guided medium e.g. twisted pair, coaxial cable, optical fiber Unguided medium e.g. air, water, vacuum ٢ Terminology

More information

KINGS COLLEGE OF ENGINEERING DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING QUESTION BANK. Subject Name: Digital Communication Techniques

KINGS COLLEGE OF ENGINEERING DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING QUESTION BANK. Subject Name: Digital Communication Techniques KINGS COLLEGE OF ENGINEERING DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING QUESTION BANK Subject Code: EC1351 Year/Sem: III/IV Subject Name: Digital Communication Techniques UNIT I PULSE MODULATION

More information

Wireless Communication Fading Modulation

Wireless Communication Fading Modulation EC744 Wireless Communication Fall 2008 Mohamed Essam Khedr Department of Electronics and Communications Wireless Communication Fading Modulation Syllabus Tentatively Week 1 Week 2 Week 3 Week 4 Week 5

More information

Principles of Baseband Digital Data Transmission

Principles of Baseband Digital Data Transmission Principles of Baseband Digital Data Transmission Prof. Wangrok Oh Dept. of Information Communications Eng. Chungnam National University Prof. Wangrok Oh(CNU) / 3 Overview Baseband Digital Data Transmission

More information

Objectives. Presentation Outline. Digital Modulation Revision

Objectives. Presentation Outline. Digital Modulation Revision Digital Modulation Revision Professor Richard Harris Objectives To identify the key points from the lecture material presented in the Digital Modulation section of this paper. What is in the examination

More information

Waveform Encoding - PCM. BY: Dr.AHMED ALKHAYYAT. Chapter Two

Waveform Encoding - PCM. BY: Dr.AHMED ALKHAYYAT. Chapter Two Chapter Two Layout: 1. Introduction. 2. Pulse Code Modulation (PCM). 3. Differential Pulse Code Modulation (DPCM). 4. Delta modulation. 5. Adaptive delta modulation. 6. Sigma Delta Modulation (SDM). 7.

More information

Part II Data Communications

Part II Data Communications Part II Data Communications Chapter 3 Data Transmission Concept & Terminology Signal : Time Domain & Frequency Domain Concepts Signal & Data Analog and Digital Data Transmission Transmission Impairments

More information

CSCD 433 Network Programming Fall Lecture 5 Physical Layer Continued

CSCD 433 Network Programming Fall Lecture 5 Physical Layer Continued CSCD 433 Network Programming Fall 2016 Lecture 5 Physical Layer Continued 1 Topics Definitions Analog Transmission of Digital Data Digital Transmission of Analog Data Multiplexing 2 Different Types of

More information

EE3723 : Digital Communications

EE3723 : Digital Communications EE3723 : Digital Communications Week 11, 12: Inter Symbol Interference (ISI) Nyquist Criteria for ISI Pulse Shaping and Raised-Cosine Filter Eye Pattern Equalization (On Board) 01-Jun-15 Muhammad Ali Jinnah

More information

EE390 Final Exam Fall Term 2002 Friday, December 13, 2002

EE390 Final Exam Fall Term 2002 Friday, December 13, 2002 Name Page 1 of 11 EE390 Final Exam Fall Term 2002 Friday, December 13, 2002 Notes 1. This is a 2 hour exam, starting at 9:00 am and ending at 11:00 am. The exam is worth a total of 50 marks, broken down

More information

Chapter 4 Digital Transmission 4.1

Chapter 4 Digital Transmission 4.1 Chapter 4 Digital Transmission 4.1 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 4-1 DIGITAL-TO-DIGITAL CONVERSION In this section, we see how we can represent

More information

EE5713 : Advanced Digital Communications

EE5713 : Advanced Digital Communications EE573 : Advanced Digital Communications Week 4, 5: Inter Symbol Interference (ISI) Nyquist Criteria for ISI Pulse Shaping and Raised-Cosine Filter Eye Pattern Error Performance Degradation (On Board) Demodulation

More information

Mobile Radio Systems OPAM: Understanding OFDM and Spread Spectrum

Mobile Radio Systems OPAM: Understanding OFDM and Spread Spectrum Mobile Radio Systems OPAM: Understanding OFDM and Spread Spectrum Klaus Witrisal witrisal@tugraz.at Signal Processing and Speech Communication Laboratory www.spsc.tugraz.at Graz University of Technology

More information

Contents Preview and Introduction Waveform Encoding

Contents Preview and Introduction Waveform Encoding Contents 1 Preview and Introduction... 1 1.1 Process of Communication..... 1 1.2 General Definition of Signal..... 3 1.3 Time-Value Definition of Signals Analog and Digital..... 6 1.3.1 Continuous Time

More information

Outline / Wireless Networks and Applications Lecture 7: Physical Layer OFDM. Frequency-Selective Radio Channel. How Do We Increase Rates?

Outline / Wireless Networks and Applications Lecture 7: Physical Layer OFDM. Frequency-Selective Radio Channel. How Do We Increase Rates? Page 1 Outline 18-452/18-750 Wireless Networks and Applications Lecture 7: Physical Layer OFDM Peter Steenkiste Carnegie Mellon University RF introduction Modulation and multiplexing Channel capacity Antennas

More information

Modulation and Coding Tradeoffs

Modulation and Coding Tradeoffs 0 Modulation and Coding Tradeoffs Contents 1 1. Design Goals 2. Error Probability Plane 3. Nyquist Minimum Bandwidth 4. Shannon Hartley Capacity Theorem 5. Bandwidth Efficiency Plane 6. Modulation and

More information

Physical Layer: Outline

Physical Layer: Outline 18-345: Introduction to Telecommunication Networks Lectures 3: Physical Layer Peter Steenkiste Spring 2015 www.cs.cmu.edu/~prs/nets-ece Physical Layer: Outline Digital networking Modulation Characterization

More information

Analyze BER Performance of Wireless FSK System

Analyze BER Performance of Wireless FSK System nalyze BER Performance of Wireless FSK System Microwaves & RF; Nov009, Vol. 48 Issue 11, p80 Hamood Shehab Hamid 1 Ekhlas Kadhum,,Widad Ismail 3, Mandeep Singh 4 1 School of Electrical and Electronics

More information

Outline / Wireless Networks and Applications Lecture 5: Physical Layer Signal Propagation and Modulation

Outline / Wireless Networks and Applications Lecture 5: Physical Layer Signal Propagation and Modulation Outline 18-452/18-750 Wireless Networks and Applications Lecture 5: Physical Layer Signal Propagation and Modulation Peter Steenkiste Carnegie Mellon University Spring Semester 2017 http://www.cs.cmu.edu/~prs/wirelesss17/

More information

Announcements : Wireless Networks Lecture 3: Physical Layer. Bird s Eye View. Outline. Page 1

Announcements : Wireless Networks Lecture 3: Physical Layer. Bird s Eye View. Outline. Page 1 Announcements 18-759: Wireless Networks Lecture 3: Physical Layer Please start to form project teams» Updated project handout is available on the web site Also start to form teams for surveys» Send mail

More information

2. By convention, the minimum and maximum values of analog data and signals are presented as voltages.

2. By convention, the minimum and maximum values of analog data and signals are presented as voltages. Chapter 2: Fundamentals of Data and Signals Data Communications and Computer Networks A Business Users Approach 8th Edition White TEST BANK Full clear download (no formatting errors) at: https://testbankreal.com/download/data-communications-computer-networksbusiness-users-approach-8th-edition-white-test-bank/

More information

Point-to-Point Communications

Point-to-Point Communications Point-to-Point Communications Key Aspects of Communication Voice Mail Tones Alphabet Signals Air Paper Media Language English/Hindi English/Hindi Outline of Point-to-Point Communication 1. Signals basic

More information

EEE482F: Problem Set 1

EEE482F: Problem Set 1 EEE482F: Problem Set 1 1. A digital source emits 1.0 and 0.0V levels with a probability of 0.2 each, and +3.0 and +4.0V levels with a probability of 0.3 each. Evaluate the average information of the source.

More information

CHAPTER 2. Instructor: Mr. Abhijit Parmar Course: Mobile Computing and Wireless Communication ( )

CHAPTER 2. Instructor: Mr. Abhijit Parmar Course: Mobile Computing and Wireless Communication ( ) CHAPTER 2 Instructor: Mr. Abhijit Parmar Course: Mobile Computing and Wireless Communication (2170710) Syllabus Chapter-2.3 Modulation Techniques Reasons for Choosing Encoding Techniques Digital data,

More information

Year : TYEJ Sub: Digital Communication (17535) Assignment No. 1. Introduction of Digital Communication. Question Exam Marks

Year : TYEJ Sub: Digital Communication (17535) Assignment No. 1. Introduction of Digital Communication. Question Exam Marks Assignment 1 Introduction of Digital Communication Sr. Question Exam Marks 1 Draw the block diagram of the basic digital communication system. State the function of each block in detail. W 2015 6 2 State

More information

Stream Information. A real-time voice signal must be digitized & transmitted as it is produced Analog signal level varies continuously in time

Stream Information. A real-time voice signal must be digitized & transmitted as it is produced Analog signal level varies continuously in time , German University in Cairo Stream Information A real-time voice signal must be digitized & transmitted as it is produced Analog signal level varies continuously in time Th e s p ee ch s i g n al l e

More information

EC6501 Digital Communication

EC6501 Digital Communication EC6501 Digital Communication UNIT -1 DIGITAL COMMUNICATION SYSTEMS Digital Communication system 1) Write the advantages and disadvantages of digital communication. [A/M 11] The advantages of digital communication

More information

Comm 502: Communication Theory. Lecture 4. Line Coding M-ary PCM-Delta Modulation

Comm 502: Communication Theory. Lecture 4. Line Coding M-ary PCM-Delta Modulation Comm 502: Communication Theory Lecture 4 Line Coding M-ary PCM-Delta Modulation PCM Decoder PCM Waveform Types (Line Coding) Representation of binary sequence into the electrical signals that enter the

More information

EECS 122: Introduction to Computer Networks Encoding and Framing. Questions

EECS 122: Introduction to Computer Networks Encoding and Framing. Questions EECS 122: Introduction to Computer Networks Encoding and Framing Computer Science Division Department of Electrical Engineering and Computer Sciences University of California, Berkeley Berkeley, CA 94720-1776

More information

Wireless Channel Propagation Model Small-scale Fading

Wireless Channel Propagation Model Small-scale Fading Wireless Channel Propagation Model Small-scale Fading Basic Questions T x What will happen if the transmitter - changes transmit power? - changes frequency? - operates at higher speed? Transmit power,

More information

KINGS DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING DIGITAL COMMUNICATION TECHNIQUES YEAR/SEM: III / VI BRANCH : ECE PULSE MODULATION

KINGS DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING DIGITAL COMMUNICATION TECHNIQUES YEAR/SEM: III / VI BRANCH : ECE PULSE MODULATION KINGS COLLEGE OF ENGINEERING DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING SUB.NAME : EC1351 DIGITAL COMMUNICATION TECHNIQUES BRANCH : ECE YEAR/SEM: III / VI UNIT I PULSE MODULATION PART A (2

More information

Chapter 3. Data Transmission

Chapter 3. Data Transmission Chapter 3 Data Transmission Reading Materials Data and Computer Communications, William Stallings Terminology (1) Transmitter Receiver Medium Guided medium (e.g. twisted pair, optical fiber) Unguided medium

More information

UNIT I Source Coding Systems

UNIT I Source Coding Systems SIDDHARTH GROUP OF INSTITUTIONS: PUTTUR Siddharth Nagar, Narayanavanam Road 517583 QUESTION BANK (DESCRIPTIVE) Subject with Code: DC (16EC421) Year & Sem: III-B. Tech & II-Sem Course & Branch: B. Tech

More information

UNIT III -- DATA AND PULSE COMMUNICATION PART-A 1. State the sampling theorem for band-limited signals of finite energy. If a finite energy signal g(t) contains no frequency higher than W Hz, it is completely

More information

CHAPTER 4. PULSE MODULATION Part 2

CHAPTER 4. PULSE MODULATION Part 2 CHAPTER 4 PULSE MODULATION Part 2 Pulse Modulation Analog pulse modulation: Sampling, i.e., information is transmitted only at discrete time instants. e.g. PAM, PPM and PDM Digital pulse modulation: Sampling

More information

Fundamentals of Data and Signals

Fundamentals of Data and Signals Fundamentals of Data and Signals Chapter 2 Learning Objectives After reading this chapter, you should be able to: Distinguish between data and signals and cite the advantages of digital data and signals

More information

APECE-302: Radio & Television Engineering

APECE-302: Radio & Television Engineering APECE-302: Radio & Television Engineering Applied Physics, Electronics & Communication Engineering LEC PPT # 01 University of Dhaka APECE DU Course Teacher: S.M. Riazul Islam, PhD Date: 2013 Year, 04 Month,

More information

Ultra Wideband Transceiver Design

Ultra Wideband Transceiver Design Ultra Wideband Transceiver Design By: Wafula Wanjala George For: Bachelor Of Science In Electrical & Electronic Engineering University Of Nairobi SUPERVISOR: Dr. Vitalice Oduol EXAMINER: Dr. M.K. Gakuru

More information

Lecture 5 Transmission

Lecture 5 Transmission Lecture 5 Transmission David Andersen Department of Computer Science Carnegie Mellon University 15-441 Networking, Spring 2005 http://www.cs.cmu.edu/~srini/15-441/s05 1 Physical and Datalink Layers: 3

More information

ECE 4600 Communication Systems

ECE 4600 Communication Systems ECE 4600 Communication Systems Dr. Bradley J. Bazuin Associate Professor Department of Electrical and Computer Engineering College of Engineering and Applied Sciences Course Topics Course Introduction

More information

CSCD 433 Network Programming Fall Lecture 5 Physical Layer Continued

CSCD 433 Network Programming Fall Lecture 5 Physical Layer Continued CSCD 433 Network Programming Fall 2016 Lecture 5 Physical Layer Continued 1 Topics Definitions Analog Transmission of Digital Data Digital Transmission of Analog Data Multiplexing 2 Different Types of

More information

Communication Channels

Communication Channels Communication Channels wires (PCB trace or conductor on IC) optical fiber (attenuation 4dB/km) broadcast TV (50 kw transmit) voice telephone line (under -9 dbm or 110 µw) walkie-talkie: 500 mw, 467 MHz

More information

Course 2: Channels 1 1

Course 2: Channels 1 1 Course 2: Channels 1 1 "You see, wire telegraph is a kind of a very, very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? And radio operates exactly

More information

Terminology (1) Chapter 3. Terminology (3) Terminology (2) Transmitter Receiver Medium. Data Transmission. Simplex. Direct link.

Terminology (1) Chapter 3. Terminology (3) Terminology (2) Transmitter Receiver Medium. Data Transmission. Simplex. Direct link. Chapter 3 Data Transmission Terminology (1) Transmitter Receiver Medium Guided medium e.g. twisted pair, optical fiber Unguided medium e.g. air, water, vacuum Corneliu Zaharia 2 Corneliu Zaharia Terminology

More information

Introduction to Digital Communications System

Introduction to Digital Communications System Wireless Information Transmission System Lab. Introduction to Digital Communications System Institute of Communications Engineering National Sun Yat-sen University Recommended Books Digital Communications

More information

ENGR 4323/5323 Digital and Analog Communication

ENGR 4323/5323 Digital and Analog Communication ENGR 4323/5323 Digital and Analog Communication Chapter 1 Introduction Engineering and Physics University of Central Oklahoma Dr. Mohamed Bingabr Course Materials Textbook: Modern Digital and Analog Communication,

More information

DEPARTMENT OF COMPUTER GCE@Bodi_ SCIENCE GCE@Bodi_ AND ENIGNEERING GCE@Bodi_ GCE@Bodi_ GCE@Bodi_ Analog and Digital Communication GCE@Bodi_ DEPARTMENT OF CsE Subject Name: Analog and Digital Communication

More information

Data and Computer Communications Chapter 3 Data Transmission

Data and Computer Communications Chapter 3 Data Transmission Data and Computer Communications Chapter 3 Data Transmission Eighth Edition by William Stallings Transmission Terminology data transmission occurs between a transmitter & receiver via some medium guided

More information

Chapter 2. Physical Layer

Chapter 2. Physical Layer Chapter 2 Physical Layer Lecture 1 Outline 2.1 Analog and Digital 2.2 Transmission Media 2.3 Digital Modulation and Multiplexing 2.4 Transmission Impairment 2.5 Data-rate Limits 2.6 Performance Physical

More information

Lecture 5 Transmission. Physical and Datalink Layers: 3 Lectures

Lecture 5 Transmission. Physical and Datalink Layers: 3 Lectures Lecture 5 Transmission Peter Steenkiste School of Computer Science Department of Electrical and Computer Engineering Carnegie Mellon University 15-441 Networking, Spring 2004 http://www.cs.cmu.edu/~prs/15-441

More information

Orthogonal Frequency Division Multiplexing & Measurement of its Performance

Orthogonal Frequency Division Multiplexing & Measurement of its Performance Available Online at www.ijcsmc.com International Journal of Computer Science and Mobile Computing A Monthly Journal of Computer Science and Information Technology IJCSMC, Vol. 5, Issue. 2, February 2016,

More information

Lecture 3: Wireless Physical Layer: Modulation Techniques. Mythili Vutukuru CS 653 Spring 2014 Jan 13, Monday

Lecture 3: Wireless Physical Layer: Modulation Techniques. Mythili Vutukuru CS 653 Spring 2014 Jan 13, Monday Lecture 3: Wireless Physical Layer: Modulation Techniques Mythili Vutukuru CS 653 Spring 2014 Jan 13, Monday Modulation We saw a simple example of amplitude modulation in the last lecture Modulation how

More information

Receiver Designs for the Radio Channel

Receiver Designs for the Radio Channel Receiver Designs for the Radio Channel COS 463: Wireless Networks Lecture 15 Kyle Jamieson [Parts adapted from C. Sodini, W. Ozan, J. Tan] Today 1. Delay Spread and Frequency-Selective Fading 2. Time-Domain

More information

Problem Sheet 1 Probability, random processes, and noise

Problem Sheet 1 Probability, random processes, and noise Problem Sheet 1 Probability, random processes, and noise 1. If F X (x) is the distribution function of a random variable X and x 1 x 2, show that F X (x 1 ) F X (x 2 ). 2. Use the definition of the cumulative

More information

Chapter 3 Digital Transmission Fundamentals

Chapter 3 Digital Transmission Fundamentals Chapter 3 Digital Transmission Fundamentals Characterization of Communication Channels Fundamental Limits in Digital Transmission CSE 323, Winter 200 Instructor: Foroohar Foroozan Chapter 3 Digital Transmission

More information