GOVERNMENT OF TAMILNADU DIRECTORATE OF TECHNICAL EDUCATION CHENNAI – 600 025 STATE PROJECT COORDINATION UNIT Diploma in Electronics And Communication Engineering Course Code: 1040 M – Scheme e-TEXTBOOK on ADVANCED COMMUNICATION SYSTEMS for V Semester DECE Convener for ECE Discipline: Dr.M.JeganMohan,M.E.,MBA.,Ph.D.,(Management).,Ph.D.,(Engg).,M.I.S.T.E., Principal, Govt. Polytechnic College, Uthappanaickanoor, Usilampatti, Madurai – 625 536 Team Members for Advanced communication systems 1.Mr.A.Sudakar,BE.,M.E., TPEVR Govt.Polytechnic College, vellore. 2.Mr.J.Ramakrishnan,BE.,PGDCA.,M.E Sakthi Polytechnic College, Erode 3. Mr.N.R.Sivakumar,BE.,M.E., Kongu polytechnic college Perunthurai, Erode Validated by Dr. S.J.Thiruvengadam, M.E.,Ph.D Professor/ECE department Thiyagaraja Engineering College, Madurai – 625 015 1 GOVERNMENT OF TAMILNADU DIRECTORATE OF TECHNICAL EDUCATION CHENNAI – 600 025 STATE PROJECT COORDINATION UNIT Diploma in Electronics and Communication Engineering Course Code: 1040 M – Scheme e-TEXTBOOK on ADVANCED COMMUNICATION SYSTEMS for V Semester DECE Convener for ECE Discipline: Dr.M.JeganMohan,M.E.,MBA.,Ph.D.,(Management).,Ph.D.,(Engg).,M.I.S.T.E., Principal, Govt. Polytechnic College, Uthappanaickanoor, Usilampatti, Madurai – 625 536 Team Members for Advanced communication systems 1.Mr.A.Sudakar,BE.,M.E., TPEVR Govt.Polytechnic College, vellore. 2. Mr.J.Ramakrishnan,BE.,PGDCA.,M.E Sakthi Polytechnic College, Erode 3. Mr.N.R.Sivakumar,BE.,M.E., Kongu polytechnic college Perunthurai,Erode Validated by Dr. S.J.Thiruvengadam,M.E.,Ph.D Professor/ECE department Thiyagaraja Engineering College, Madurai – 625 015 2 UNIT-1 RADAR AND NAVIGATIONAL AIDS: Basic Radar System– Applications – Radar Range Equation (Qualitative Treatment Only) – Factors Influencing Maximum Range – Basic Pulsed Radar System – Block Diagram – Display Methods- A - Scope, PPI Display - Instrument Landing System – Ground Controlled Approach System. TELEPHONY AND FAX: Telephone System–Public Switched Telephone Network (PSTN) - Electronic Switching System – Block Diagram – ISDN – Architecture, Features - Video Phone – Block Diagram. FACSIMILE COMMUNICATION SYSTEM: Facsimile Sender-Cylindrical Scanning – Facsimile Receiver- Synchronization – Phasing - Index Of Cooperation (IOC) - Direct Recording. UNIT-II DIGITAL COMMUNICATION: Basic Elements Of Digital Communication System - Block Diagram-Characteristics Of Data Transmission Circuits - Bandwidth Requirement – Speed - Baud Rate - Noise - Crosstalk – Distortion. DIGITAL CODES: ASCII Code – EBCDIC Code - Error Detection Codes – Parity Check Codes – Redundant Codes - Error Correction Codes – Retransmission- Forward Error Correcting Code – Hamming Code - Digital Modulation Techniques – ASK, FSK, PSK, QPSK Modulation/Demodulation Techniques (Only Block Diagram And Operation). UNIT-III OPTICAL COMMUNICATION: Optical Communication System – Block Diagram – Advantages Of Optical Fiber Communication Systems – Principles Of Light Transmission In A Fiber Using Ray Theory – Single Mode Fibers, Multimode Fibers – Step Index Fibers, Graded Index Fibers (Basic Concepts Only) – Attenuation In Optical Fibers – Absorption Losses, Scattering Losses, Bending Losses, Core And Cladding Losses Optical Sources – LED - Semiconductor LASER – Principles – Optical Detectors – PIN And APD Diodes - Connectors - Splices – Couplers – Optical Transmitter – Block Diagram – Optical Receiver – Block Diagram - Application Of Optical Fibers – Networking, Industry And Military Applications. UNIT-IV SATELLITE COMMUNICATION: Satellite system: Kepler’s I,II,II laws – orbits – launching orbits – types - Geostationary synchronous satellites - Advantages – Apogee – Perigee - Active and passive satellite - Earth eclipse of satellite. Antenna: Parabolic reflector antenna – cassegrain antenna. Space segment: Power supply- Attitude control- station keeping – Transponders – TT and C subsystem – Antenna subsystem. Earth segment: Block diagram of Transmit receive earth station - Satellite mobile services - Basics of GPS. MICROWAVE COMMUNICATION: Microwave frequency ranges - microwave devices – Parametric amplifiers –Travelling wave tubes – simple block diagram of microwave transmitter, receiver and microwave link repeater UNIT-V MOBILE COMMUNICATION: (Qualitative Treatment only) Cellular telephone– fundamental concepts – Simplified Cellular telephone system - frequency reuse – Interference – Co-channel Interference – Adjacent Channel Interference – Improving coverage and capacity in cellular systems - cell splitting – sectoring – Roaming and Handoff – Basics of blue tooth technology. SATELLITE MULTIPLE ACCESS TECHNIQUES: TDMA, FDMA, CDMA. Digital cellular system – Global system for mobile communications (GSM) –GSM services - GSM System Architecture – Basics of GPRS. 3 CONTENTS SYLLABUS UNIT – I RADAR AND NAVIGATION AIDS 5-23 UNIT – II DIGITAL COMMUNICATION 24-53 UNIT – III OPTICAL COMMUNICATION 54-84 UNIT – IV SATELLITE COMMUNICATION 85-114 UNIT – IV MOBILE COMMUNICATION 115-142 4 Unit – 1 Radar and Navigational Aids Introduction Radar is a device used to monitor objects present far away with the help of radio waves. It is used to check whether any object is present in the area under search, the distance from the radar to the object and the velocity of the object, based on need. Navigational aids are the devices used to help the vehicles moving in sea or air where no sign boards could be used. Radar- fundamentals The term RADAR refers to RAdio Detection And Ranging. It contains a transmitter and a receiver, each connected to a directional antenna. The transmitter sends a Ultra High Frequency (UHF) or Microwave signal and the reflected echo signal from the target is measured at the receiver. If pulsed signal used in the transmitter, the distance between the transmitter and the target will be calculated by calculating the time taken by the signal to reach receiver. If Continuous wave is used in the transmitter, the speed and direction of movement of the target will be calculated by measuring the difference in frequency of the signal as per Doppler effect. Basic Radar System The block diagram of pulsed radar shown in fig.1.1 consists of a transmitter and receiver, each connected to a directional antenna. The transmitter is capable of sending out a large UHF or microwave power through the antenna. 5 The receiver collects as much energy as possible from the echoes reflected in its direction by the target, and process the received signal and displays this information in a suitable way. The receiving antenna is same as the transmitting antenna. This is achieved through a kind of time division multiplexing arrangements, since the radio energy is sent out in the form of pulses. The pulse is transmitted through the antenna. Echo signals or reflected signals from the object reach the antenna after some time delay. Because of this time delay same antenna is used for transmission and reception using Time Division Multiplexing Techniques. Applications The major applications of Radars include but not limited to searching a target in free space or sea, tracking a target to follow the trajectory of the target, altitude measurement of a aircraft. Radar can be employed as navigational aid in several ways. It has numerous military uses. Radar equipment in an aircraft can provide useful information for navigation. Radar equipment on a ship gives the information about the land masses, other ships etc . In military services radar is used for aiming guns at ship, aircraft, directing guided missiles etc. In addition radar finds important uses in aiding the landing of aircraft, in monitoring air traffic, in the airports and in enabling the height of the aircraft above ground. Radar range equation As the distance between the RADAR Transmitter and the target increases, the reflected signal power that reaches the RADAR Receiver decreases. There will be a minimum identifiable power that the RADAR Receiver can handle properly. This minimum power decides the maximum distance between the RADAR and the target, which is commonly known as Maximum Range of the RADAR. The maximum range Rmax is obtained when the received power is equal to the minimum received power of the receiver Pmin. The maximum range Rmax is given by 1 2 푃푡 퐴0 푆 4 푅푚푎푥 = { 2 } ----------------------------------------------- 4휋휆 푃푚푖푛 1 Where Pt = Peak value of the transmitted pulse power. A0 = capture area of the receiving antenna . S = Effective cross section area of the Target (Commonly known as Radar cross section) Pmin = minimum received power λ = wavelength of the transmitted signal 6 Factors influencing Maximum Range The radar equation is given by 1 2 푃푡 퐴0 푆 4 푅푚푎푥 = { 2 } ---------------------------------------------------------------2 4휋휆 푃푚푖푛 1. From the above equation the maximum range is proportional to the fourth root of the peak transmitted pulse power. The peak power must be increased 16 times to double the maximum range, keeping all the other parameters in the equation constant. Such a power increase obviously becomes very expensive. 2. A decrease in minimum receivable power will have the same effect as raising the transmitting power and is thus very attractive alternate to it. 3. Radar range equation also shows that maximum range proportional to the square root of the capture area of the antenna and therefore directly proportional to its diameter. Hence doubling a given maximum radar range is to be double the effective diameter of the antenna. 4. Also the Rmax can be increased by increasing frequency.