CP Course Introduction

8/8/2019 CP Course Introduction

1/34

Communication Principles -EGR2173 1

Communication PrinciplesIntroduction


2/34


Principles and Learning ObjectivesDefine the terms communication andtelecommunications and describe the components of atelecommunications system.Name the four main elements of any communicationssystem and state what each does.Identify three basic types of communications media anddiscuss the basic characteristics of each.Define bandwidth and compute the bandwidth of a givenpiece of spectrum, given the upper and lower frequencyranges.

Define modulation and explain why it is necessary andimportant.List six examples of common simplex and duplexcommunications systems in wide use today .List the twelve major segments of the electromagnetic

spectrum and give the frequency ranges of each.


3/34


Definition : Communications

1.Communication is the process of exchanging information.- Frenzel

2.Communication refers to the sending,receiving and processing of information byelectronic means.- Kennedy


4/34


Elements of a communications system

The major elements of a

communications system are atransmitter to send a message, acommunications medium, a receiver

to pick up the message, and noise.


5/34


Communications


6/34


Communications


7/34


Telecommunications


8/34


Ty pes of Electronic Communications

categoriesOne way or two ways

Analog or digitalBaseband or modulated signals


9/34


B andwidth - The range of frequencies that an

electronic signal occupies on a giventransmission medium.B roadband - Telecommunications in which awide band of frequencies is available to transmit

information, allowing more information to betransmitted in a given amount of time.Noise random,undesirable electrical energythat enters the communication system via the

communication medium and interferes with thetransmitted message


10/34


BAS EBA ND S IGNA LS

B aseband signals have their originalinformation in the form of analog and digital

signalsPutting the original voice, video or digital

signal directl y into the medium is referred toas baseband transmission


11/34


M ODULA TION

To transmit baseband signals b y radio, modulationtechniques must be used.Techniques using modulation are referred to asbroadband.M odulation is the process of having a baseband voice,video, or digital signal ( modulating signal ) modif y another, higher-frequenc y signal called the carrier.The carrier is usuall y the sine wave that is higher infrequenc yThree basic characteristics of the carrier can be changedb y the information signal: amplitude, frequenc y andphaseTwo most common methods of modulation are amplitudemodulation ( A M ) and frequenc y modulation ( F M )


12/34


M ULTIPLEXING

M ultiplexing is the process of transmitting two or more signals simultaneousl y over the samechannelThere are multiplexing for analog signals anddigital signals.A lso true for baseband and broadband methodsof multiplexing

ExamplesF DMTDMW DM


13/34


Multiplexing

A multiplexer enables a single communication

channel to carry data from multiple senderssimultaneouslyFrequency Division Multiplexing Analog signals

Senders use separate frequenciesTime Division Multiplexing Digital signals Transmits in rotation of senders


14/34


Ty pes of Electronic Communications

Simplex channel a communications channelthat can transmit data in only one direction

Half-duplex a communications channel thatcan transmit data in either direction, but notsimultaneouslyFull-duplex channel - a communications channel

that permit data transmission in both directionsat the same time


15/34


CommunicationA pplications

A M & F M radio broadcastingTV broadcastingW ireless remote control.Paging servicesNavigation & direction finding servicesTelemetr yRadio astronom yTelephones

FacsimileRadar A mateur radioLA N


16/34


Videoconferencing


17/34


ELEC TRONI C DATA

INTE

R CH

ANGE

(E

DI)C OMPUT E R - TO - C OMPUT E R

EXCH ANG E BE TW EE N TWOORGANIZATIONS

OF STANDARD BUSIN E SS

TRANSAC

TION DOC

UME NTS

*CO M P UTER CO M P UTER

S ELLE R CUS TOM ER

ORD ERS , P AY M EN TS

SH IPPING NO TICE S , P R ICE

UP DATES , INVOICE S


18/34


WIR ELE SS TRANSMISSION

TECH

NOL

OGIE

S

PERSONAL COMMUNICATION

SERVICE: C ellular; lower power; higher frequency. Smaller phones not shielded by

buildings, tunnelsPERSONAL DIGITAL ASSISTANT: Pensized, hand-held, digital communicator SMART PHONE: Wireless, voice, text,Internet

*


19/34


Cellular Transmission


20/34


C OMMUNI C ATION CH ANN EL SME ANS BY W H ICH DATA AR E TRANSMITT E D:

TWISTED WIRES (C opper Wires)COAXIAL CABLE: (Insulated C opper Wires)FIBER-OPTIC CABLE

MICROWAVE: A high volume, long distance, point-to-point transmission in which high frequency radiosignals are transmitted through atmosphere from oneterrestrial transmission to another

*


21/34


SUP E R CLE AR G L ASS STRANDS

FAST, L IGH T, DURAB LEUP TO T E N BI LL ION BITS P E R S EC OND, FU LL DUP LEXEX PE NSIV E , H ARD E R TO INSTA LL

OFT E N US E D AS BACKBONE OF N E TWORKS*

FIB E R OPTI C S

S IGNA LS IGNA L LAS ERLAS ER CAB LECAB LEP H OTOP H OTO

DETEC TORDETEC TORS IGNA LS IGNA L


22/34


L OW-ORBIT SAT ELL ITE

UPLINKUPLINK

M ICROW AVEM ICROW AVETR A NS M ISS IONTR A NS M ISS ION

DOW NLINKDOW NLINK


23/34


S atellite Transmission


24/34


Microwaves - SatellitesGE Os are 35,000km above E arthLE Os are


25/34


Microwaves


26/34


The ElectromagneticS pectrum


27/34


Radio Waves

Radio waves have the longest wavelengths in theelectromagnetic spectrum. These waves can be longer than a football field or as short as a football. Radiowaves do more than just bring music to your radio. The y also carr y signals for your television and cellular phones.Cellular phones also use radio waves to transmitinformation. These waves are much smaller that TV andFM radio waves.


28/34


Microwaves


29/34


M icrowaves have wavelengths that can be measuredin centimeters! The longer microwaves, those closer to a foot in length, are the waves which heat our foodin a microwave oven.M icrowaves are good for transmitting informationfrom one place to another because microwaveenerg y can penetrate haze, light rain and snow,clouds, and smoke.

S horter microwaves are used in remote sensing.These microwaves are used for radar like thedoppler radar used in weather forecasts.M icrowaves, used for radar, are just a few incheslong.

M icrowaves


30/34


ELF 30 to 300 H z

Include A C power line ( 50 or 60 H z )Voice Frquencies

VF 300 ~ 3000 H z H uman speech

Ver y Low Frquencies Include higher end of of the human hearing range M usical instruments

Used in some government & militar y communication Used b y nav y for submarine communication

Extremel y Low Frequencies


31/34


30 to 300 k H z

used in aeronautical and marine navigationM edium Frequencies

300 to 3000 k H z ( 3 M H z ) A M radio broadcasting ( 535 ~ 1605 k H z )

A lso Used in marine & aeronauticalcommunication applications.H igh Frequencies

3 ~ 30 M H z

A

lso known as short waves 2 wa y communication A mateur radio

Low Frequencies


32/34


30 to 300 M H z

mobile radio, marine & aeronauticalcommunication applications.

FM radio broadcasting ( 88 ~ 108 M H z ) TV channel 2 ~ 13

Ultra H igh Frequencies 300 ~ 30000 M H z TV channel 14 ~ 67 Land mobile communication cellular telephone

M

ilitar y services Radio amateurs A bove 1 G H z > microwaves

Ver y H igh Frequencies


33/34


30 to 300 M H z

mobile radio, marine & aeronauticalcommunication applications. FM radio broadcasting ( 88 ~ 108 M H z ) TV channel 2 ~ 13

Extremel y H

igh Frequencies 300 ~ 30000 M H z TV channel 14 ~ 67 Land mobile communication cellular telephone M ilitar y services Radio amateurs A bove 1 G H z > microwaves

S uper H igh Frequencies


34/34


Microwave - terrestrial station

Stationed 40-50 km apart.Must have direct line-of-sight to transmit.Often mounted on

buildings or mountains.

CP Course Introduction

Documents