Digital Modulation Lecture 01. Review of Analogue Modulation Introduction to Digital Modulation Techniques Richard Harris

Size: px
Start display at page:

Download "Digital Modulation Lecture 01. Review of Analogue Modulation Introduction to Digital Modulation Techniques Richard Harris"

Transcription

1 Digital Modulation Lecture 01 Review of Analogue Modulation Introduction to Digital Modulation Techniques Richard Harris

2 Objectives You will be able to: Classify the various approaches to Analogue Modulation Discuss the basic methodologies involved in Digital Modulation Amplitude Modulation Frequency Modulation Phase Modulation Describe the concepts behind binary modulated bandpass signalling Communication Systems Digital Modulation Slide 2

3 Presentation Outline Review of Analogue Modulation Techniques Introduction to Digital Modulation methods Binary Modulated Bandpass Signalling Unipolar and Bipolar Examples of OOK etc Communication Systems Digital Modulation Slide 3

4 Review of Analogue Modulation - 1 We have found that Placing baseband signals on high frequency carriers using the process of modulation facilitates the long distance transmission of data, voice and video signals. Since they can be tied more efficiently to the communication medium, the high frequency waves travel over greater distances than could be achieved with the original message / waveform unaided. Modulation: The signal processing technique where, at the transmitter one signal (the modulating signal) modifies a property of another signal (the carrier signal) so that a composite wave (the modulated wave) is formed. Communication Systems Digital Modulation Slide 4

5 Review of Analogue Modulation - 2 Demodulation At the receiver, the modulating signal is recovered from the modulated wave (demodulation). The bandwidth of the modulated wave is equal to, or greater than the bandwidth of the modulating signal. Since the modulated wave has a higher frequency it can be launched from: Practical sized antennas Moderate sized cables or waveguides Each symbol represents a specific sequence of bits and the symbol set covers all possible bit combinations. The maximum symbol rate is determined by the passband of the bearer and associated equipment. Communication Systems Digital Modulation Slide 5

6 Analogue Modulation Analogue modulation combines a higher frequency sinusoidal carrier with a lower frequency signal carrying the message. Such carriers can be modulated in three distinct ways Amplitude A can be varied in sympathy with the message Amplitude Modulation Frequency f can be varied according to the message signal Frequency Modulation Phase φ can also be varied with the message signal. Phase modulation Note that collectively, frequency and phase modulation are referred to as angle modulation. Communication Systems Digital Modulation Slide 6

7 What is Digital Modulation? Digital Modulation combines a high frequency sinusoidal carrier signal and a digital data stream to create a modulated wave that assumes a limited number of states. As for Amplitude Modulation, we can modulate the wave in sympathy with the digital data stream in three basic ways: Amplitude A can be varied in sympathy with the message Amplitude Modulation Frequency f can be varied according to the message signal Frequency Modulation Phase φ can also be varied with the message signal. Phase modulation Communication Systems Digital Modulation Slide 7

8 Why Digital Modulation - 1 Most communication systems can be classified into one of three different categories: Bandwidth efficient Ability of system to accommodate data within a prescribed bandwidth Power efficient Reliable sending of data with minimal power requirements Cost efficient System needs to be affordable in the context of its use Communication Systems Digital Modulation Slide 8

9 Why Digital Modulation - 2 Move from Analogue (AM) to Digital (DM) since it provides better information capacity, higher data security, better quality communications. Industry trends: Signal/System Complexity AM, FM Scalar signals QAM, FSK, QPSK Vector signals TDMA, CDMA Time variant signals Required Measurement Capability Communication Systems Digital Modulation Slide 9

10 Why Digital Modulation - 3 Another layer of complexity in many new systems is multiplexing. Two principal types of multiplexing (or multiple access ) are TDMA (Time Division Multiple Access) and CDMA (Code Division Multiple Access). These are two different ways to add diversity to signals allowing different signals to be separated from one another. Communication Systems Digital Modulation Slide 10

11 Transmitting Information A pure carrier is generated at the transmitter. The carrier is modulated with the information to be transmitted. Any reliably detectable change in signal characteristics can carry information. At the receiver the signal modifications or changes are detected and demodulated. Modulation Modify a signal Demodulation Detect the modifications Communication Systems Digital Modulation Slide 11

12 Polar Display - 1 Polar display - magnitude and phase represented together A simple way to view amplitude and phase is with the polar diagram. The carrier becomes a frequency and phase reference and the signal is interpreted relative to the carrier. The signal can be expressed in polar form as a magnitude and a phase. The phase is relative to a reference signal, Usually the carrier in most communication systems. Communication Systems Digital Modulation Slide 12

13 Polar Display - 2 Magnitude is represented as the distance from the centre and phase is represented as the angle. Amplitude modulation (AM) changes only the magnitude of the signal. Phase modulation (PM) changes only the phase of the signal. Amplitude and phase modulation can be used together. Frequency modulation (FM) looks similar to phase modulation, though frequency is the controlled parameter, rather than relative phase. Communication Systems Digital Modulation Slide 13

14 I/Q Formats In digital communications, modulation is often expressed in terms of I and Q. This is a rectangular representation of the polar diagram. On a polar diagram, the I axis lies on the zero degree phase reference, and the Q axis is rotated by 90 degrees. The signal vector s projection onto the I axis is its I component and the projection onto the Q axis is its Q component. Communication Systems Digital Modulation Slide 14

15 I and Q in Transmitter I/Q diagrams are useful since they mirror the way in which digital communication signals are created using an I/Q modulator. In the transmitter, I and Q signals are mixed with the same local oscillator. A 90 o phase shifter is placed on one of the paths. Signals that are at 90 o are said to be orthogonal to each other or in quadrature. Communication Systems Digital Modulation Slide 15

16 Transmitter Side Q Local Oscillator 90 o Phase Shift Σ Composite output signal I Signals that are in quadrature are independent and do not interfere with each other. Simplifies digital radios and similar devices Communication Systems Digital Modulation Slide 16

17 Receiver Side Quadrature component Composite input signal Local Oscillator 90 o Phase Shift In-phase component On the receiver side, the combined signals are easily separated out Communication Systems Digital Modulation Slide 17

18 Why use I/Q? Digital Modulation is easy to accomplish with I/Q modulators. Most modulators map data onto a number of discrete points on the I-Q plane. Points are known as constellation points. As the signal moves from one point to another, simultaneous amplitude and phase modulation usually takes place. Difficult to achieve in conventional phase modulators. Communication Systems Digital Modulation Slide 18

19 Application Areas Modulation Format MSK, GMSK BPSK QPSK and ¼p DQPSK OQPSK FSK, GFSK 8, 16 VSB 8PSK 16 QAM 32 QAM 64 QAM 256 QAM Application GSM and CDPD Deep space telemetry, cable modems Satellite, CDMA, NADC, TETRA, PHS, PDC, LMDS CDMA, satellite DECT, paging, RAM mobile data, AMPS, CT2, land mobile and public safety North American digital TV Satellite, aircraft Microwave digital radio, modems, DVB-C, DVB-T Terrestrial microwave, DVB-T DVB-C modems, set top boxes MMDS Modems, Digital video (USA) Communication Systems Digital Modulation Slide 19

20 MSK and GMSK Minimum-shift keying (MSK) is a type of continuous phase frequency-shift keying. Similarly to OQPSK, MSK is encoded with bits alternating between quarternary components, with the Q component delayed by half a bit period. However, instead of square pulses as OQPSK uses, MSK encodes each bit as a half sinusoid. This results in a constant-modulus signal, which reduces problems caused by non-linear distortion. The resulting signal is represented by the formula where a I (t) and a Q (t) are the square pulses as shown in QPSK. A similar modulation scheme is Gaussian minimum shift keying, which uses Gaussian instead of sinusoidal pulse shapes. Retrieved from " Communication Systems Digital Modulation Slide 20

21 Digital Modulation The modulating signal m(t) is a digital signal given by Binary line codes or Multi-level line codes Correspondingly, the bandpass signals are also given by Binary line codes or Multi-level line codes Communication Systems Digital Modulation Slide 21

22 Binary Modulated Bandpass Signalling Examples 1 We shall illustrate a number of binary signal formats in the following sequence of slides. Unipolar A 1 is represented by a current of 2A signal units and a 0 is represented by a current of zero signal units. Communication Systems Digital Modulation Slide 22

23 Binary Modulated Bandpass Signalling Examples 2 Unipolar actually can occur in two forms, viz: Non return to zero (NRZ) Current maintained for entire bit period (time slot) In a long sequence with equally likely 1s and 0s, power is ½ (2A 2 ) or 2A 2 signal watts Return to zero (RZ) Currents are maintained for a fraction of the time slot. If we assume that the current is maintained for ½ the time slot and the symbols are equally likely, then the power in this case is ½ x 2A 2 = A 2 signal watts. Consider the sequence and view the following diagrams to compare the two cases. Communication Systems Digital Modulation Slide 23

24 Binary Modulated Bandpass Signalling Examples 3 With Non Return to Zero operation: Long sequences of 0s produce periods where there is no current generated Long sequences of 1s produce periods where positive current is generated When the 1s and 0s are equally likely, the mean value is A signal units. Each of the above conditions can cause problems for an electronic receiver, viz: When a constant current or no current flows there is no timing information and synchronisation is difficult. Unipolar (Non Return to Zero) Communication Systems Digital Modulation Slide 24

25 Binary Modulated Bandpass Signalling Examples 4 With Return to Zero operation: Long sequences of 0s produce periods where there is no current generated Long sequences of 1s produce periods where positive current is generated for a fraction of the time and hence a change can be detected by the receiver. When the 1s and 0s are equally likely and the pulses are ½ T wide, the mean value is A/2 signal units. So RZ eliminates the timing problem, but not the problem of long term level shifts. Communication Systems Digital Modulation Slide 25

26 Bipolar operation: Binary Modulated Bandpass Signalling Examples 5 A 1 is represented by a current of +A signal units A 0 is represented by a current of A signal units Two modes of operation, once again: Non Return to Zero Currents maintained for entire time slot Power needed for equally likely symbols is A 2 signal watts Return to Zero Currents maintained for fraction of time slot Power needed for equally likely symbols is A 2 /2 signal watts Communication Systems Digital Modulation Slide 26

27 Binary Modulated Bandpass Signalling Examples 6 Bipolar Non Return to Zero Bipolar Return to Zero Communication Systems Digital Modulation Slide 27

28 Binary Modulated Bandpass Signalling Examples 7 Long strings of 1s or 0s produce constant currents in NRZ bipolar and these represent a problem for electronic circuits once again. For RZ bipolar, these problems are basically eliminated because the receiver detects the return to zero in each pulse period. When 1s and 0s are equally likely, the mean signal value is just zero. Communication Systems Digital Modulation Slide 28

29 Biphase (or Manchester) Binary Modulated Bandpass Signalling Examples 8 A 1 is a positive current of amplitude A signal units that changes to a negative current pulse of equal magnitude and a 0 is a negative pulse that changes to a positive current pulse of equal magnitude. The change-over occurs at the midpoint of the timeslot. This type of coding is used between equipment that operates at a high speed and requires close synchronisation. Communication Systems Digital Modulation Slide 29

30 Binary Modulated Bandpass Signalling Examples 9 Alternate Mark Inversion (AMI) 1s are represented by return to zero current pulses of equal magnitude A that alternate between positive and negative. 0s are represented by the absence of current pulses. Power requirements are A 2 /4 which is half of RZ bipolar and one eighth of NRZ bipolar. Since the polarity alternates, almost all the power is contained within a bandwidth equal to the bit rate expressed in Hz. With a pulse shape that is approximately the same as a raised cosine, AMI is used extensively in the USA T1 carrier systems. Communication Systems Digital Modulation Slide 30

31 Binary Modulated Bandpass Signalling Examples 10 Two binary, one quaternary (2B1Q) Four signal levels (±3 and ±1) each represent a pair of bits. Of each pair, the first bit determines whether the level is positive or negative (1 = +ve, and 0 = -ve) Communication Systems Digital Modulation Slide 31

32 Comments on 2B1Q Signalling amplitude time Usually described as distance 2 : -3, -1, +1, +3 2B1Q signalling is used for BISDN basic rate services (at 160kbps) and ISDN digital subscriber loop services. For long sequences of 1s and 0s, or alternating 1s and 0s (ie ) 2B1Q signalling produces constant currents and synchronisation is impossible. Since the frequency power density spectrums of 2B1Q, AMI and Raised Cosine are lower, they are employed in bandwidth limited environments such as telephone connections. Manchester is used in LANs and other applications where precise synchronisation is important and bandwidth is available. Communication Systems Digital Modulation Slide 32

Objectives. Presentation Outline. Digital Modulation Lecture 01

Objectives. Presentation Outline. Digital Modulation Lecture 01 Digital Modulation Lecture 01 Review of Analogue Modulation Introduction to Digital Modulation Techniques Richard Harris Objectives You will be able to: Classify the various approaches to Analogue Modulation

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

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

COSC 3213: Computer Networks I: Chapter 3 Handout #4. Instructor: Dr. Marvin Mandelbaum Department of Computer Science York University Section A

COSC 3213: Computer Networks I: Chapter 3 Handout #4. Instructor: Dr. Marvin Mandelbaum Department of Computer Science York University Section A COSC 3213: Computer Networks I: Chapter 3 Handout #4 Instructor: Dr. Marvin Mandelbaum Department of Computer Science York University Section A Topics: 1. Line Coding: Unipolar, Polar,and Inverted ; Bipolar;

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

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

Chapter 7 Multiple Division Techniques for Traffic Channels

Chapter 7 Multiple Division Techniques for Traffic Channels Introduction to Wireless & Mobile Systems Chapter 7 Multiple Division Techniques for Traffic Channels Outline Introduction Concepts and Models for Multiple Divisions Frequency Division Multiple Access

More information

UNIT 2 DIGITAL COMMUNICATION DIGITAL COMMUNICATION-Introduction The techniques used to modulate digital information so that it can be transmitted via microwave, satellite or down a cable pair is different

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

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

COMPUTER COMMUNICATION AND NETWORKS ENCODING TECHNIQUES

COMPUTER COMMUNICATION AND NETWORKS ENCODING TECHNIQUES COMPUTER COMMUNICATION AND NETWORKS ENCODING TECHNIQUES Encoding Coding is the process of embedding clocks into a given data stream and producing a signal that can be transmitted over a selected medium.

More information

Mobile & Wireless Networking. Lecture 2: Wireless Transmission (2/2)

Mobile & Wireless Networking. Lecture 2: Wireless Transmission (2/2) 192620010 Mobile & Wireless Networking Lecture 2: Wireless Transmission (2/2) [Schiller, Section 2.6 & 2.7] [Reader Part 1: OFDM: An architecture for the fourth generation] Geert Heijenk Outline of Lecture

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

CS441 Mobile & Wireless Computing Communication Basics

CS441 Mobile & Wireless Computing Communication Basics Department of Computer Science Southern Illinois University Carbondale CS441 Mobile & Wireless Computing Communication Basics Dr. Kemal Akkaya E-mail: kemal@cs.siu.edu Kemal Akkaya Mobile & Wireless Computing

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

Hello and welcome to today s lecture. In the last couple of lectures we have discussed about various transmission media.

Hello and welcome to today s lecture. In the last couple of lectures we have discussed about various transmission media. Data Communication Prof. Ajit Pal Department of Computer Science & Engineering Indian Institute of Technology, Kharagpur Lecture No # 7 Transmission of Digital Signal-I Hello and welcome to today s lecture.

More information

Digital to Digital Encoding

Digital to Digital Encoding MODULATION AND ENCODING Data must be transformed into signals to send them from one place to another Conversion Schemes Digital-to-Digital Analog-to-Digital Digital-to-Analog Analog-to-Analog Digital to

More information

Modulation (7): Constellation Diagrams

Modulation (7): Constellation Diagrams Modulation (7): Constellation Diagrams Luiz DaSilva Professor of Telecommunications dasilval@tcd.ie +353-1-8963660 Adapted from material by Dr Nicola Marchetti Geometric representation of modulation signal

More information

Wireless Communications

Wireless Communications 2. Physical Layer DIN/CTC/UEM 2018 Periodic Signal Periodic signal: repeats itself in time, that is g(t) = g(t + T ) in which T (given in seconds [s]) is the period of the signal g(t) The number of cycles

More information

3/26/18. Lecture 3 EITN STRUCTURE OF A WIRELESS COMMUNICATION LINK

3/26/18. Lecture 3 EITN STRUCTURE OF A WIRELESS COMMUNICATION LINK Lecture 3 EITN75 208 STRUCTURE OF A WIRELESS COMMUNICATION LINK 2 A simple structure Speech Data A/D Speech encoder Encrypt. Chann. encoding Modulation Key Speech D/A Speech decoder Decrypt. Chann. decoding

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

Signal Encoding Techniques

Signal Encoding Techniques Signal Encoding Techniques Overview Have already noted previous chapters that both analog and digital information can be encoded as either analog or digital signals: Digital data, digital signals: simplest

More information

MODULATION AND MULTIPLE ACCESS TECHNIQUES

MODULATION AND MULTIPLE ACCESS TECHNIQUES 1 MODULATION AND MULTIPLE ACCESS TECHNIQUES Networks and Communication Department Dr. Marwah Ahmed Outlines 2 Introduction Digital Transmission Digital Modulation Digital Transmission of Analog Signal

More information

CHETTINAD COLLEGE OF ENGINEERING & TECHNOLOGY NH-67, TRICHY MAIN ROAD, PULIYUR, C.F , KARUR DT.

CHETTINAD COLLEGE OF ENGINEERING & TECHNOLOGY NH-67, TRICHY MAIN ROAD, PULIYUR, C.F , KARUR DT. CHETTINAD COLLEGE OF ENGINEERING & TECHNOLOGY NH-67, TRICHY MAIN ROAD, PULIYUR, C.F. 639 114, KARUR DT. DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING COURSE MATERIAL Subject Name: Analog & Digital

More information

Data Communications and Networking (Module 2)

Data Communications and Networking (Module 2) Data Communications and Networking (Module 2) Chapter 5 Signal Encoding Techniques References: Book Chapter 5 Data and Computer Communications, 8th edition, by William Stallings 1 Outline Overview Encoding

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

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

C06a: Digital Modulation

C06a: Digital Modulation CISC 7332X T6 C06a: Digital Modulation Hui Chen Department of Computer & Information Science CUNY Brooklyn College 10/2/2018 CUNY Brooklyn College 1 Outline Digital modulation Baseband transmission Line

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

Chapter 2: Wireless Transmission. Mobile Communications. Spread spectrum. Multiplexing. Modulation. Frequencies. Antenna. Signals

Chapter 2: Wireless Transmission. Mobile Communications. Spread spectrum. Multiplexing. Modulation. Frequencies. Antenna. Signals Mobile Communications Chapter 2: Wireless Transmission Frequencies Multiplexing Signals Spread spectrum Antenna Modulation Signal propagation Cellular systems Prof. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/

More information

Chapter 7. Multiple Division Techniques

Chapter 7. Multiple Division Techniques Chapter 7 Multiple Division Techniques 1 Outline Frequency Division Multiple Access (FDMA) Division Multiple Access (TDMA) Code Division Multiple Access (CDMA) Comparison of FDMA, TDMA, and CDMA Walsh

More information

Class 4 ((Communication and Computer Networks))

Class 4 ((Communication and Computer Networks)) Class 4 ((Communication and Computer Networks)) Lesson 5... SIGNAL ENCODING TECHNIQUES Abstract Both analog and digital information can be encoded as either analog or digital signals. The particular encoding

More information

21. Orthonormal Representation of Signals

21. Orthonormal Representation of Signals 1. Orthonormal Representation of Signals Introduction An analogue communication system is designed for the transmission of information in analogue form. he source information is in analogue form. In practice,

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

ECE5713 : Advanced Digital Communications

ECE5713 : Advanced Digital Communications ECE5713 : Advanced Digital Communications Bandpass Modulation MPSK MASK, OOK MFSK 04-May-15 Advanced Digital Communications, Spring-2015, Week-8 1 In-phase and Quadrature (I&Q) Representation Any bandpass

More information

Mobile Communication An overview Lesson 03 Introduction to Modulation Methods

Mobile Communication An overview Lesson 03 Introduction to Modulation Methods Mobile Communication An overview Lesson 03 Introduction to Modulation Methods Oxford University Press 2007. All rights reserved. 1 Modulation The process of varying one signal, called carrier, according

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

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

Digital modulation techniques

Digital modulation techniques Outline Introduction Signal, random variable, random process and spectra Analog modulation Analog to digital conversion Digital transmission through baseband channels Signal space representation Optimal

More information

DIGITAL COMMUNICATIONS SYSTEMS. MSc in Electronic Technologies and Communications

DIGITAL COMMUNICATIONS SYSTEMS. MSc in Electronic Technologies and Communications DIGITAL COMMUNICATIONS SYSTEMS MSc in Electronic Technologies and Communications Bandpass binary signalling The common techniques of bandpass binary signalling are: - On-off keying (OOK), also known as

More information

Amplitude Modulation, II

Amplitude Modulation, II Amplitude Modulation, II Single sideband modulation (SSB) Vestigial sideband modulation (VSB) VSB spectrum Modulator and demodulator NTSC TV signsals Quadrature modulation Spectral efficiency Modulator

More information

Modulation is the process of impressing a low-frequency information signal (baseband signal) onto a higher frequency carrier signal

Modulation is the process of impressing a low-frequency information signal (baseband signal) onto a higher frequency carrier signal Modulation is the process of impressing a low-frequency information signal (baseband signal) onto a higher frequency carrier signal Modulation is a process of mixing a signal with a sinusoid to produce

More information

RF Basics 15/11/2013

RF Basics 15/11/2013 27 RF Basics 15/11/2013 Basic Terminology 1/2 dbm is a measure of RF Power referred to 1 mw (0 dbm) 10mW(10dBm), 500 mw (27dBm) PER Packet Error Rate [%] percentage of the packets not successfully received

More information

Digital data (a sequence of binary bits) can be transmitted by various pule waveforms.

Digital data (a sequence of binary bits) can be transmitted by various pule waveforms. Chapter 2 Line Coding Digital data (a sequence of binary bits) can be transmitted by various pule waveforms. Sometimes these pulse waveforms have been called line codes. 2.1 Signalling Format Figure 2.1

More information

EE3723 : Digital Communications

EE3723 : Digital Communications EE3723 : Digital Communications Week 8-9: Bandpass Modulation MPSK MASK, OOK MFSK 04-May-15 Muhammad Ali Jinnah University, Islamabad - Digital Communications - EE3723 1 In-phase and Quadrature (I&Q) Representation

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

Chapter 6 Passband Data Transmission

Chapter 6 Passband Data Transmission Chapter 6 Passband Data Transmission Passband Data Transmission concerns the Transmission of the Digital Data over the real Passband channel. 6.1 Introduction Categories of digital communications (ASK/PSK/FSK)

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

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

CHAPTER 2 DIGITAL MODULATION

CHAPTER 2 DIGITAL MODULATION 2.1 INTRODUCTION CHAPTER 2 DIGITAL MODULATION Referring to Equation (2.1), if the information signal is digital and the amplitude (lv of the carrier is varied proportional to the information signal, a

More information

Radio Technology and Architectures. 1 ENGN4521/ENGN6521: Embedded Wireless L#1

Radio Technology and Architectures. 1 ENGN4521/ENGN6521: Embedded Wireless L#1 Radio Technology and Architectures 1 ENGN4521/ENGN6521: Embedded Wireless L#1 Radio (Architectures) Spectrum plan and legal issues Radio Architectures and components 2 ENGN4521/ENGN6521: Embedded Wireless

More information

Wireless Networks. Why Wireless Networks? Wireless Local Area Network. Wireless Personal Area Network (WPAN)

Wireless Networks. Why Wireless Networks? Wireless Local Area Network. Wireless Personal Area Network (WPAN) Wireless Networks Why Wireless Networks? rate MBit/s 100.0 10.0 1.0 0.1 0.01 wired terminals WMAN WLAN CORDLESS (CT, DECT) Office Building stationary walking drive Indoor HIPERLAN UMTS CELLULAR (GSM) Outdoor

More information

Digital Modulators & Line Codes

Digital Modulators & Line Codes Digital Modulators & Line Codes Professor A. Manikas Imperial College London EE303 - Communication Systems An Overview of Fundamental Prof. A. Manikas (Imperial College) EE303: Dig. Mod. and Line Codes

More information

COMM 601: Modulation I

COMM 601: Modulation I Prof. Ahmed El-Mahdy, Communications Department The German University in Cairo Text Books [1] Couch, Digital and Analog Communication Systems, 7 th edition, Prentice Hall, 2007. [2] Simon Haykin, Communication

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

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

Real and Complex Modulation

Real and Complex Modulation Real and Complex Modulation TIPL 4708 Presented by Matt Guibord Prepared by Matt Guibord 1 What is modulation? Modulation is the act of changing a carrier signal s properties (amplitude, phase, frequency)

More information

Communication Systems

Communication Systems Electronics Engineering Communication Systems Comprehensive Theory with Solved Examples and Practice Questions Publications Publications MADE EASY Publications Corporate Office: 44-A/4, Kalu Sarai (Near

More information

6. Modulation and Multiplexing Techniques

6. Modulation and Multiplexing Techniques 6. Modulation and Multiplexing Techniques The quality of analog transmission is S/N (signal to noise ratio). signal power S/N = ---------------------------- baseband noise power S/N can be greater than

More information

Thus there are three basic modulation techniques: 1) AMPLITUDE SHIFT KEYING 2) FREQUENCY SHIFT KEYING 3) PHASE SHIFT KEYING

Thus there are three basic modulation techniques: 1) AMPLITUDE SHIFT KEYING 2) FREQUENCY SHIFT KEYING 3) PHASE SHIFT KEYING CHAPTER 5 Syllabus 1) Digital modulation formats 2) Coherent binary modulation techniques 3) Coherent Quadrature modulation techniques 4) Non coherent binary modulation techniques. Digital modulation formats:

More information

AM Limitations. Amplitude Modulation II. DSB-SC Modulation. AM Modifications

AM Limitations. Amplitude Modulation II. DSB-SC Modulation. AM Modifications Lecture 6: Amplitude Modulation II EE 3770: Communication Systems AM Limitations AM Limitations DSB-SC Modulation SSB Modulation VSB Modulation Lecture 6 Amplitude Modulation II Amplitude modulation is

More information

Chapter 5: Modulation Techniques. Abdullah Al-Meshal

Chapter 5: Modulation Techniques. Abdullah Al-Meshal Chapter 5: Modulation Techniques Abdullah Al-Meshal Introduction After encoding the binary data, the data is now ready to be transmitted through the physical channel In order to transmit the data in the

More information

Data Encoding. Two devices are used for producing the signals: CODECs produce DIGITAL signals MODEMs produce ANALOGUE signals

Data Encoding. Two devices are used for producing the signals: CODECs produce DIGITAL signals MODEMs produce ANALOGUE signals Data Encoding Data are propagated from point to point by encoding data into signals The data may be analogue or digital Likewise the signals may be analogue or digital Two devices are used for producing

More information

Instant data transmission in daily use

Instant data transmission in daily use International Journal of Scientific and Research Publications, Volume 5, Issue 9, September 2015 1 Instant data transmission in daily use Manjunisha Baby Chouhan 1, Bhawani pratap rathore 2, Vikash Yadav

More information

Lecture Outline. Data and Signals. Analogue Data on Analogue Signals. OSI Protocol Model

Lecture Outline. Data and Signals. Analogue Data on Analogue Signals. OSI Protocol Model Lecture Outline Data and Signals COMP312 Richard Nelson richardn@cs.waikato.ac.nz http://www.cs.waikato.ac.nz Analogue Data on Analogue Signals Digital Data on Analogue Signals Analogue Data on Digital

More information

Amplitude Modulation II

Amplitude Modulation II Lecture 6: Amplitude Modulation II EE 3770: Communication Systems Lecture 6 Amplitude Modulation II AM Limitations DSB-SC Modulation SSB Modulation VSB Modulation Multiplexing Mojtaba Vaezi 6-1 Contents

More information

(Refer Slide Time: 2:23)

(Refer Slide Time: 2:23) Data Communications Prof. A. Pal Department of Computer Science & Engineering Indian Institute of Technology, Kharagpur Lecture-11B Multiplexing (Contd.) Hello and welcome to today s lecture on multiplexing

More information

ECE 4203: COMMUNICATIONS ENGINEERING LAB II

ECE 4203: COMMUNICATIONS ENGINEERING LAB II DEPARTMENT OF ELECTRICAL & COMPUTER ENGINEERING ECE 4203: COMMUNICATIONS ENGINEERING LAB II SEMESTER 2, 2017/2018 DIGITAL MODULATIONS INTRODUCTION In many digital communication systems, cable (as for data

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

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

6. has units of bits/second. a. Throughput b. Propagation speed c. Propagation time d. (b)or(c)

6. has units of bits/second. a. Throughput b. Propagation speed c. Propagation time d. (b)or(c) King Saud University College of Computer and Information Sciences Information Technology Department First Semester 1436/1437 IT224: Networks 1 Sheet# 10 (chapter 3-4-5) Multiple-Choice Questions 1. Before

More information

9.4. Synchronization:

9.4. Synchronization: 9.4. Synchronization: It is the process of timing the serial transmission to properly identify the data being sent. There are two most common modes: Synchronous transmission: Synchronous transmission relies

More information

Chapter 14 MODULATION INTRODUCTION

Chapter 14 MODULATION INTRODUCTION Chapter 14 MODULATION INTRODUCTION As we have seen in previous three chapters, different types of media need different types of electromagnetic signals to carry information from the source to the destination.

More information

College of information Technology Department of Information Networks Telecommunication & Networking I Chapter 5. Analog Transmission

College of information Technology Department of Information Networks Telecommunication & Networking I Chapter 5. Analog Transmission Analog Transmission 5.1 DIGITAL-TO-ANALOG CONVERSION Digital-to-analog conversion is the process of changing one of the characteristics of an analog signal based on the information in digital data. The

More information

Lecture-8 Transmission of Signals

Lecture-8 Transmission of Signals Lecture-8 Transmission of Signals The signals are transmitted as electromagnetic waveforms. As the signal may be analog or digital, there four case of signal transmission. Analog data Analog Signal:- The

More information

Data Encoding g(p (part 2)

Data Encoding g(p (part 2) Data Encoding g(p (part 2) CSE 3213 Instructor: U.T. Nguyen 10/11/2007 12:44 PM 1 Analog Data, Digital Signals (5.3) 2 1 Analog Data, Digital Signals Digitization Conversion of analog data into digital

More information

END-OF-YEAR EXAMINATIONS ELEC321 Communication Systems (D2) Tuesday, 22 November 2005, 9:20 a.m. Three hours plus 10 minutes reading time.

END-OF-YEAR EXAMINATIONS ELEC321 Communication Systems (D2) Tuesday, 22 November 2005, 9:20 a.m. Three hours plus 10 minutes reading time. END-OF-YEAR EXAMINATIONS 2005 Unit: Day and Time: Time Allowed: ELEC321 Communication Systems (D2) Tuesday, 22 November 2005, 9:20 a.m. Three hours plus 10 minutes reading time. Total Number of Questions:

More information

Introduction to Communications Part Two: Physical Layer Ch5: Analog Transmission. Goals of This Class. Warm Up. Outline of the Class

Introduction to Communications Part Two: Physical Layer Ch5: Analog Transmission. Goals of This Class. Warm Up. Outline of the Class Introduction to Communications Part Two: Physical Layer Ch5: Analog Transmission Kuang Chiu Huang TCM NCKU Spring/2008 2009/4/11 KuangChiu Huang 1 Goals of This Class Through the lecture of analog transmission,

More information

2. TELECOMMUNICATIONS BASICS

2. TELECOMMUNICATIONS BASICS 2. TELECOMMUNICATIONS BASICS The purpose of any telecommunications system is to transfer information from the sender to the receiver by a means of a communication channel. The information is carried by

More information

ECE230X Lectures 10-11

ECE230X Lectures 10-11 ECE230X Lectures 10-11 Data and Computer Communications Eighth Edition By William Stallings Section 5.2 Digital Data, Analog Signals D. Richard Brown III Worcester Polytechnic Institute Electrical and

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

ISHIK UNIVERSITY Faculty of Science Department of Information Technology Fall Course Name: Wireless Networks

ISHIK UNIVERSITY Faculty of Science Department of Information Technology Fall Course Name: Wireless Networks ISHIK UNIVERSITY Faculty of Science Department of Information Technology 2017-2018 Fall Course Name: Wireless Networks Agenda Lecture 4 Multiple Access Techniques: FDMA, TDMA, SDMA and CDMA 1. Frequency

More information

(Refer Slide Time: 01:45)

(Refer Slide Time: 01:45) Digital Communication Professor Surendra Prasad Department of Electrical Engineering Indian Institute of Technology, Delhi Module 01 Lecture 21 Passband Modulations for Bandlimited Channels In our discussion

More information

On-off keying, which consists of keying a sinusoidal carrier on and off with a unipolar binary signal

On-off keying, which consists of keying a sinusoidal carrier on and off with a unipolar binary signal Bandpass signalling Thus far only baseband signalling has been considered: an information source is usually a baseband signal. Some communication channels have a bandpass characteristic, and will not propagate

More information

Structure of the Lecture

Structure of the Lecture Structure of the Lecture Chapter 2 Technical Basics: Layer 1 Methods for Medium Access: Layer 2 Representation of digital signals on an analogous medium Signal propagation Characteristics of antennas Chapter

More information

Principles of Communications ECS 332

Principles of Communications ECS 332 Principles of Communications ECS 332 Asst. Prof. Dr. Prapun Suksompong prapun@siit.tu.ac.th 5. Angle Modulation Office Hours: BKD, 6th floor of Sirindhralai building Wednesday 4:3-5:3 Friday 4:3-5:3 Example

More information

Vector Signal Analyzer FSE-B7 for Spectrum Analyzers FSE

Vector Signal Analyzer FSE-B7 for Spectrum Analyzers FSE Vector Signal Analyzer FSE-B7 for Spectrum Analyzers FSE Universal demodulation, analysis and documentation of digital and analog mobile radio signals For all major mobile radio communication standards:

More information

Electronics Interview Questions

Electronics Interview Questions Electronics Interview Questions 1. What is Electronic? The study and use of electrical devices that operate by controlling the flow of electrons or other electrically charged particles. 2. What is communication?

More information

Chapter 4. Part 2(a) Digital Modulation Techniques

Chapter 4. Part 2(a) Digital Modulation Techniques Chapter 4 Part 2(a) Digital Modulation Techniques Overview Digital Modulation techniques Bandpass data transmission Amplitude Shift Keying (ASK) Phase Shift Keying (PSK) Frequency Shift Keying (FSK) Quadrature

More information

AN INTRODUCTION OF ANALOG AND DIGITAL MODULATION TECHNIQUES IN COMMUNICATION SYSTEM

AN INTRODUCTION OF ANALOG AND DIGITAL MODULATION TECHNIQUES IN COMMUNICATION SYSTEM AN INTRODUCTION OF ANALOG AND DIGITAL MODULATION TECHNIQUES IN COMMUNICATION SYSTEM Rashmi Pandey Vedica Institute of Technology, Bhopal Department of Electronics & Communication rashmipandey07@rediffmail.com

More information

Communications IB Paper 6 Handout 5: Multiple Access

Communications IB Paper 6 Handout 5: Multiple Access Communications IB Paper 6 Handout 5: Multiple Access Jossy Sayir Signal Processing and Communications Lab Department of Engineering University of Cambridge jossy.sayir@eng.cam.ac.uk Lent Term Jossy Sayir

More information

Lecture 2 Fiber Optical Communication Lecture 2, Slide 1

Lecture 2 Fiber Optical Communication Lecture 2, Slide 1 Lecture 2 General concepts Digital modulation in general Optical modulation Direct modulation External modulation Modulation formats Differential detection Coherent detection Fiber Optical Communication

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

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

Outline. EECS 3213 Fall Sebastian Magierowski York University. Review Passband Modulation. Constellations ASK, FSK, PSK.

Outline. EECS 3213 Fall Sebastian Magierowski York University. Review Passband Modulation. Constellations ASK, FSK, PSK. EECS 3213 Fall 2014 L12: Modulation Sebastian Magierowski York University 1 Outline Review Passband Modulation ASK, FSK, PSK Constellations 2 1 Underlying Idea Attempting to send a sequence of digits through

More information

Signals and codes. Path and modulation

Signals and codes. Path and modulation Signals and codes Path and modulation Communication system The goal is to transfer a status message from source to destination. Signal quality is decreased by channel noise / interference Transferred message

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

INTRODUCTION TO COMMUNICATION SYSTEMS AND TRANSMISSION MEDIA

INTRODUCTION TO COMMUNICATION SYSTEMS AND TRANSMISSION MEDIA COMM.ENG INTRODUCTION TO COMMUNICATION SYSTEMS AND TRANSMISSION MEDIA 9/9/2017 LECTURES 1 Objectives To give a background on Communication system components and channels (media) A distinction between analogue

More information

Contents. 7.1 Line Coding. Dr. Ali Muqaibel [Principles of Digital Transmission ]

Contents. 7.1 Line Coding. Dr. Ali Muqaibel [Principles of Digital Transmission ] Contents 7.1 Line Coding... 1 Performance Criteria of Line Codes... 4 Advanced Examples in Line Coding: High Density Bipolar (HDBN)... 5 7. Power Spectral Density of Line Codes... 5 7.3 Pulse shaping and

More information

I-Q transmission. Lecture 17

I-Q transmission. Lecture 17 I-Q Transmission Lecture 7 I-Q transmission i Sending Digital Data Binary Phase Shift Keying (BPSK): sending binary data over a single frequency band Quadrature Phase Shift Keying (QPSK): sending twice

More information