Welcome to the subjectWelcome to the subject

EKT 231EKT 231

COMMUNICATION SYSTEMCOMMUNICATION SYSTEM

LECTURERSLECTURERS

1.1. En. Rosnazri Bin AliEn. Rosnazri Bin Ali

04-985162604-9851626

rosnazrirosnazri@unimap.edu.my@unimap.edu.my

2.2. Pn. Siti Rafidah Bt. Abdul rahimPn. Siti Rafidah Bt. Abdul rahim

04-979890904-9798909

rafidah@kukum.edu.myrafidah@kukum.edu.my

SYNOPSISSYNOPSISThe aim of this subject is : The aim of this subject is :

to introduce the students with the basic principles to introduce the students with the basic principles and components of communications system.and components of communications system.

This subject will cover various topics such as:This subject will cover various topics such as: Introduction to Communication System, Introduction to Communication System, Analog Modulation and Demodulation (e.g. Analog Modulation and Demodulation (e.g.

Amplitude Modulation), Amplitude Modulation), Angle Modulation (Frequency Modulation and Phase Angle Modulation (Frequency Modulation and Phase

Modulation), Modulation), Digital Modulation, Digital Modulation, Noise in Communication System, Transmission Noise in Communication System, Transmission

System and Transmission Lines.System and Transmission Lines.

OBJECTIVESOBJECTIVES

To understand the basic components in a wire To understand the basic components in a wire line and wireless communication system for line and wireless communication system for analog and digital transmission.analog and digital transmission.

To emphasize on the importance of To emphasize on the importance of modulation and demodulation of analog modulation and demodulation of analog signals along with associated system design signals along with associated system design issues.issues.

To introduce the student with the types of To introduce the student with the types of analogue and digital modulation techniques analogue and digital modulation techniques those are used in present telecommunication those are used in present telecommunication system.system.

To characterize amplitude, double-sideband To characterize amplitude, double-sideband and single sideband modulated waveforms in and single sideband modulated waveforms in the time and the frequency domains.the time and the frequency domains.

OBJECTIVES (Cont’d)OBJECTIVES (Cont’d) To characterize frequency and phase modulated To characterize frequency and phase modulated

signals in the time domain and tone modulated signals in the time domain and tone modulated signals in the frequency domain.signals in the frequency domain.

To study the quantization process in a pulse To study the quantization process in a pulse code modulation system in terms of how it is code modulation system in terms of how it is created and how to minimize its effect.created and how to minimize its effect.

To study the characteristic of noise and its effect To study the characteristic of noise and its effect on the communications system.on the communications system.

To study and analyze the modulated analog and To study and analyze the modulated analog and digital signals performance in the presence of digital signals performance in the presence of additive noise.additive noise.

To enhance the students’ knowledge on To enhance the students’ knowledge on transmission line those are used in transmission line those are used in communication system.communication system.

ReferencesReferences

Wayne Tomasi, “ Wayne Tomasi, “ Electronic Communication Electronic Communication Systems Fundamentals Through AdvancedSystems Fundamentals Through Advanced” 5th Ed, ” 5th Ed, Prentice Hall, 2004.Prentice Hall, 2004.

Paul Young, “Electronics Communications Paul Young, “Electronics Communications Techniques”, 5Techniques”, 5thth Edition, Prentice Hall, 2004. Edition, Prentice Hall, 2004.

Mullet , “Basic Telecommunications:The Physical Mullet , “Basic Telecommunications:The Physical Layer”, Thomson Learning, 2003.Layer”, Thomson Learning, 2003.

AssessmentAssessment

Final Exam = 50 %Final Exam = 50 %

Coursework = 50 %Coursework = 50 % Test x2 Test x2 = 15 %= 15 % LabsLabs = 30 % (lab work 20%, lab = 30 % (lab work 20%, lab test 10%)test 10%) Assignments/quizzes = 5%Assignments/quizzes = 5%

CHAPTER 1CHAPTER 1INTRODUCTION TO INTRODUCTION TO

COMMUNICATION SYSTEMCOMMUNICATION SYSTEM

DefinitionsDefinitions Communications:Communications:

Transfer of information from one place to another.Transfer of information from one place to another. Should be efficient, reliable, and secured.Should be efficient, reliable, and secured.

Communication system:Communication system: components/subsystems act together to accomplish components/subsystems act together to accomplish

information transfer/exchangeinformation transfer/exchange

Definitions (Cont’d)Definitions (Cont’d)

Electronic communication systemElectronic communication systemtransmission, reception and transmission, reception and

processing of information processing of information between two or more locations between two or more locations using electronic circuits.using electronic circuits.

Information sourceInformation sourceanalog/digital formanalog/digital form

Information, message Information, message and signalsand signals

InformationInformation The commodity produced by the source The commodity produced by the source

for transfer to some user at the for transfer to some user at the destination.destination.

MessageMessage The physical manifestation of information The physical manifestation of information

as produced by the information source.as produced by the information source. SignalsSignals

A physical embodiment of information – A physical embodiment of information – voltage signal or current signalvoltage signal or current signal

Need For CommunicationNeed For Communication

Importance of communication:Importance of communication:

exchange of information exchange of information between two parties separated between two parties separated in distances in a more faster and in distances in a more faster and reliable way.reliable way.

Information transfer system block Information transfer system block diagramdiagram

Processing(modulator)

Transmitter

Receiver /Processing

(demodulator)Transducers

Information sources > Audio > Video > Data(with their respective transducers)

Audio

Video

Data

Reproduced information

Transmission medium

Think!Think!

Have you ever pictured yourself living in a Have you ever pictured yourself living in a world without any communication system?world without any communication system?

Development and Development and progressprogress

Communications between human beingsCommunications between human beings Form of hand gestures and facial Form of hand gestures and facial

expressionsexpressions Verbal grunts and groansVerbal grunts and groans

Long distance communicationsLong distance communications Smoke signalsSmoke signals Light, mirror reflectionLight, mirror reflection TelegraphTelegraph TelephoneTelephone

Cont’d…Cont’d…

Wireless radio signalsWireless radio signals Spark-gap transmitterSpark-gap transmitter Continuous carrier wave Continuous carrier wave

transmitter (with the invention of transmitter (with the invention of triode vacuum tubes)triode vacuum tubes)

Commercial radio broadcastingCommercial radio broadcasting Satellite communicationsSatellite communications Mobile telephonesMobile telephones

Early wireless telegraph stationEarly wireless telegraph station(using spark-gap transmitter)(using spark-gap transmitter)

Receiver

Transmitter

Notice that the person is wearing a belt that full with vacuum tubes !

Vacuum tubeThe first transistor

Brief History in CommunicationBrief History in Communication

YearYear EventsEvents1844 1844 Telegraph – Telegraph – Samuel B. MorseSamuel B. Morse18621862 Prediction of electromagnetic Prediction of electromagnetic waves propagation through a waves propagation through a

vacuum vacuum – – James Clerk MaxwellJames Clerk Maxwell1876 1876 Telephone – Telephone – Alexander Graham Alexander Graham

BellBell18881888 Proved of EM waves existence – Proved of EM waves existence –

Heinrich HertzHeinrich Hertz18951895 Wireless telegraph – Wireless telegraph – G. MarconiG. Marconi19041904 Invention of diode vacuum tube – Invention of diode vacuum tube –

John John Fleming Fleming1906 1906 Invention of triode vacuum tube – Invention of triode vacuum tube – Lee Lee

de Forestde Forest

cont’d….cont’d….

YearYear EventsEvents

19061906 Amplitude modulation (AM) – Amplitude modulation (AM) –

Reginald FessendenReginald Fessenden

1920 1920 11stst radio broadcast (AM, in radio broadcast (AM, in US)US)

1923 1923 Television - Television - Vladimir Vladimir ZworykinZworykin

1933 1933 Frequency modulation (FM) – Frequency modulation (FM) – Edwin H. ArmstrongEdwin H. Armstrong

19411941 FM radio broadcast (US)FM radio broadcast (US)

19481948 Invention of transistorInvention of transistor

cont’d….cont’d….

19571957 First satellite (Sputnik, First satellite (Sputnik, Russia)Russia)

19661966 Optical links using Optical links using laser and laser and fiber opticsfiber optics

1972 Cellular Telephone1972 Cellular Telephone

1989 Internet1989 Internet

Analog vs. DigitalAnalog vs. Digital AnalogAnalog

Continuous VariationContinuous Variation Assume the total range of Assume the total range of

frequencies/timefrequencies/time All information is transmittedAll information is transmitted

DigitalDigital Takes samples:Takes samples:

non continuous stream of on/off pulsesnon continuous stream of on/off pulses Translates to 1’s and 0’sTranslates to 1’s and 0’s

Analog vs. DigitalAnalog vs. Digital Digital CSDigital CSAdvantagesAdvantages::-Privacy preserved(data -Privacy preserved(data

encrypted)encrypted)-Can merge different -Can merge different

datadata-error correction-error correction- high immunity to noise- high immunity to noise

Disadvantages:Disadvantages:-synchronization -synchronization

problem is relatively problem is relatively difficultdifficult

Analog CSAnalog CSDisadvantages:Disadvantages:-No privacy preserved-No privacy preserved-Cannot merge different -Cannot merge different

datadata-No error correction -No error correction

capabilitycapability- Susceptible to noise- Susceptible to noiseAdvantages:Advantages:-synchronization -synchronization

problem is relatively problem is relatively easier.easier.

Basic Requirements of Basic Requirements of Communication SystemCommunication System

Rate of information transfer:Rate of information transfer: how fast the information can be how fast the information can be

transferredtransferred Purity of signal received:Purity of signal received:

whether the signal received is the whether the signal received is the same as the signal being transmitsame as the signal being transmit

Simplicity of the systemSimplicity of the system the simpler the system, the better the simpler the system, the better

ReliabilityReliability

Trade-off between analog and Trade-off between analog and digital modulationsdigital modulations

Simple modulation and hardware

Simple demodulationand hardware

Complex modulationand hardware

Complex demodulationand hardware

Analog modulation

Digital modulation

Wide bandwidth medium

Narrow bandwidth medium

Signals and Systems DefinedSignals and Systems Defined

A A signalsignal is any physical phenomenon which is any physical phenomenon which conveys informationconveys information

SystemsSystems respond to respond to signalssignals and produce new and produce new signalssignals

ExcitationExcitation signalssignals are applied at are applied at systemsystem inputsinputs and and responseresponse signalssignals are produced at are produced at systemsystem outputsoutputs

A Communication System as a A Communication System as a System ExampleSystem Example

A A communication systemcommunication system has an has an information information signalsignal plus plus noise signals noise signals

This is an example of a This is an example of a systemsystem that consists of an that consists of an interconnection of smaller interconnection of smaller systemssystems

Signal TypesSignal Types

Conversions Between Signal Conversions Between Signal TypesTypes

Sampling

Quantizing

Encoding

Sound Recording SystemSound Recording System

Recorded Sound as a Signal Recorded Sound as a Signal ExampleExample

““s”s” “i”“i” “gn” “gn” “al”“al”

Elements of Elements of Communication Communication

System(CS)System(CS)

W2-1

Elements of CS(cont’d)Elements of CS(cont’d)

Information Information The communication system exists to The communication system exists to

convey a message.convey a message. Message comes from information Message comes from information

sourcesource Information forms - audio, video, text Information forms - audio, video, text

or dataor data

cont’d…cont’d… Transmitter: Transmitter:

Processes input signal to produce a Processes input signal to produce a transmitted signal that suited the transmitted signal that suited the characteristic of transmission channel. characteristic of transmission channel.

E.g. modulation, coding, mixing, translateE.g. modulation, coding, mixing, translate Other functions performed - Amplification, Other functions performed - Amplification,

filtering, antennafiltering, antenna Message converted to into electrical Message converted to into electrical

signals by transducerssignals by transducers E.g. speech waves are converted to E.g. speech waves are converted to

voltage variation by a microphonevoltage variation by a microphone

Elements of CS(cont’d)Elements of CS(cont’d)

Channel (transmission media):Channel (transmission media): a medium that bridges the distance a medium that bridges the distance

from source to destination. Eg: from source to destination. Eg: Atmosphere (free space), wires, coaxial Atmosphere (free space), wires, coaxial cable, fiber optics, waveguidecable, fiber optics, waveguide

signals undergoes degradation from signals undergoes degradation from noise , interference and distortionnoise , interference and distortion

Elements of CS(cont’d)Elements of CS(cont’d)

Receiver: Receiver: to recover the message signal contained in to recover the message signal contained in

the received signal from the output of the the received signal from the output of the channel, and convert it to a form suitable for channel, and convert it to a form suitable for the output transducer. the output transducer.

E.g. mixing, demodulation, decodingE.g. mixing, demodulation, decoding Other functions performed: Amplification, Other functions performed: Amplification,

filtering.filtering. Transducer converts the electrical signal at Transducer converts the electrical signal at

its input into a form desired by the system its input into a form desired by the system usedused

Various forms of Various forms of communication systemcommunication system

Broadcast: radio and televisionBroadcast: radio and television Mobile communicationsMobile communications Fixed communication system- land Fixed communication system- land

lineline Data communication-internetData communication-internet