Engr Fundamental Ideas

Engr What is Communication ?? Exchange Of Information

Engr What is Communication?? Exchange Of Information

Engr I get it !!!!!!!!!!!! My Information. Audio Video Data Signal Free Space Copper Fiber Optic Source Destination Transfer of information from one place to another Transmission Medium

Engr How to transfer information?? Some carrier is required to carry information over long distances…. Why??? Through Some Carrier Limitation: Information cannot go beyond certain distance without the aid of a carrier

Engr Carrier Should be capable of carrying information Can take it through long distance Should have good speed Which is the most suitable carrier??

Engr Electromagnetic Wave Highest Known speed 3x10 8 m/s Can carry any information through modulation Energetic - Can go through long distance Supports multiple media Eg: Free space/Copper/Fiber etc..

Engr Electromagnetic Wave In electromagnetic wave electrical and magnetic fields vary harmonically Harmonic oscillations at atomic level gives oscillating electric field Electromagnetic wave generation

Engr Relation between electric and magnetic field Changing electric field gives rise to changing magnetic field & vise versa (Perpendicular) So in electromagnetic wave electric and magnetic fields oscillate perpendicular to each other and electromagnetic energy transmits perpendicular to both

Engr Figure of a wave Wavelength = distance travelled in one cycle( ) Frequency = Number of cycles per second( ) Velocity(v) = x

Engr Velocity of all the electromagnetic wave is same, 3 x 10 8 m/s Electro Magnetic Spectrum

Engr Block Diagram of a Telecommunication System

Engr What is the other thing required apart from carrier for transmitting signals over longer distances?? Some medium for carrying signals from transmitter to the receiver Media…..

Engr Different types of media used for transmitting signals…. Wired : Twisted Pair Co-axial cable Optical fiber Wireless(Free space/air):Microwave Satellite Rx MEDIA Tx Carrier

Engr Twisted Pair

Engr  Twisted pair is made of two copper wires which are covered by plastics or materials that are similar  The insulated wires are twisted to form the communication line,the purpose of twisting the wires is to avoid electrical interference  Twisted pair can be combined into a cable that may consist of two,four,fifty or hundreds of pairs  Twisted pair is the basis of transmission media(Telephone) Twisted Pair

Engr Coaxial Cable

Engr  Coaxial cable contains two conductors which are insulated from one another  The inner conductor is covered by the dielectric and the outer conductor is covered by a shield  Coaxial cable has many applications,for instance cable TV,local networks,short run computer system links and long distance telephone transmission  In local network coaxial cable can support different type of traffic and data  By using FDM,it can carry more than 10,000 channels at a time Coaxial Cable

Engr Optic Fiber

Engr Optic Fiber(Physical Appearance)

Engr Optic fiber is made up of 3 parts : Core,Cladding and jacket  The inner most part is the core which contains one or more thin fibers that are made up of plastic or glass  Each of the fiber in the core is covered by a cladding which has different optical properties from the core  The outer most part of the optical fiber is made up of plastic or other materials,which is called the jacket Optic Fiber

Engr  Because of greater performance and higher data rate,the application of optic fiber has dramatically increased in long distance communication and military applications Optic Fiber

Engr Microwave

Microwave  In terrestrial microwave transmission a pair of towers mounted on top of the towers will transmit signals through air  Microwave antennas are equipped in higher place in order to achieve better transmission effect  Voice transmission,television transmission and the short point to point links will be the major application of microwave transmission

Engr Satellite Communication

Engr Satellite  A satellite consists of several transponders which receive signal from one frequency band,this action is called uplink  The satellite will amplify or repeat the signal to other frequency band,this action is called downlink  A satellite link is called a microwave link  The most application of satellite communication will be long distance telephone transmission  Private business networks and television distribution

Engr Comparison of Twisted Pair,Coaxial Cable and Optic fiber Twisted Pair Coaxial Cable Optic Fiber Data Rate/ Bandwidth 4Mbps500MbpsUpto 100Gbps Repeater Spacing1-10Km Km ElectromagnetismAffected Not affected

Engr Comparison of Satellite and Optic Fiber Optic FiberSatellite ReconfigurationNot possiblePossible BandwidthPracticallyupto 10GHz 36-72MHz Weather ConditionAffected by stormNot affected by storm Electromagnetic Interference Not affectedAffected