Chap 1 Introduction to Data Communication Systems.pptx

Introduction to data comm

1. CSE-303 Data Communication Dr. Ibrar Ullah 1

2. Logistics of this course Text book: Data Communications and Networking by Behrouz A Forouzan , 4th Edition (Text book) Data and Computer Communications by William Stallings , Sixth Edition , Publisher Prentice Hall Computer Networks, 3rd edition by Andrew S. Tannenbaum Computer Networks: A Systems Approach, 3rd Edition by Larry Peterson, Bruce Davie , Morgan Kaufman Publishers Computer Networking: A Top down Approach Featuring the Internet by Kurose Assessment Mid Term (25%) Written (Long Questions, Short Questions, MCQs)   Final Term (50%) Written (Long Questions, Short Questions, MCQs) Sessional (25%) Assignments (10%), Quiz (15%) 2

3. What is Communication ?????? EE-494 Wireless Comm. by Dr. Ibrar 3

4. Methods of communication: Face to face Written words (letters) Electrical innovations: Telegraph Telephone Radio Television Internet (computer) Human Communication EE-494 Wireless Comm. by Dr. Ibrar 4

5. 5 Data Communications “ Data Communication is the exchange of Information from one entity to the other using a Transmission Medium ” An example of a Simple Data Communication System: Message Sender Receiver Medium Protocol

6. A Communications Model EE-494 Wireless Comm. by Dr. Ibrar 6

7. A relatively complex Data Communication System 7

8. Basic Communication System EE-494 Wireless Comm. by Dr. Ibrar 8

9. Basic Communication System Basic components: Transmitter Channel or medium Receiver Noise degrades or interferes with transmitted information. EE-494 Wireless Comm. by Dr. Ibrar 9

10. The transmitter is a collection of electronic components and circuits that converts the electrical signal into a signal suitable for transmission over a given medium. Transmitters are made up of oscillators, amplifiers, tuned circuits and filters, modulators, frequency mixers, frequency synthesizers, and other circuits. Transmitter EE-494 Wireless Comm. by Dr. Ibrar 10

11. The communication channel is the medium by which the electronic signal is sent from one place to another. Types of media include Electrical conductors Optical media Free space/ Wireless media System-specific media (e.g., water for sonar). Communication Channel EE-494 Wireless Comm. by Dr. Ibrar 11

12. A receiver is a collection of electronic components and circuits that accepts the transmitted message from the channel and converts it back into a form understandable by humans. Receivers contain amplifiers, oscillators, mixers, tuned circuits and filters, and a demodulator or detector that recovers the original information signal from the modulated carrier. Receivers EE-494 Wireless Comm. by Dr. Ibrar 12

13. A transceiver is an electronic unit that incorporates circuits that both send and receive signals. Examples are: Telephones Fax machines Cell phones Computer modems Transceivers EE-494 Wireless Comm. by Dr. Ibrar 13

14. Signal attenuation , or degradation, exists in all types of media wire/wireless. It is proportional to the square of the distance between the transmitter and receiver. Signal Attenuation EE-494 Wireless Comm. by Dr. Ibrar 14

15. Noise is random, undesirable electronic energy that enters the communication system via the communicating medium and interferes with the transmitted message. Noise EE-494 Wireless Comm. by Dr. Ibrar 15

16. 16 Fundamental Characteristics of a DCS The effectiveness of a data communication system depend on three fundamental characteristics: Delivery Accuracy Timelines Jetter

17. Communication Systems are classified according to whether they are One-way ( S implex ) or two-way ( Half duplex or F ull duplex ) transmissions. Analog or digital . Types of Communication System EE-494 Wireless Comm. by Dr. Ibrar 17

18. The simplest method of electronic communication is referred to as simplex . This type of communication is one-way. Examples are: Radio TV broadcasting Simplex EE-494 Wireless Comm. by Dr. Ibrar 18

19. The form of two-way communication in which only one party transmits at a time is known as half duplex . Examples are: Police/military radio transmissions Walky Talky HAM Radio etc. Half Duplex EE-494 Wireless Comm. by Dr. Ibrar 19

20. HAM Radio Amateur radio (also called ham radio ) is the use of designated radio frequency spectrum for purposes of private recreation, non-commercial exchange of messages, wireless experimentation, self-training, and emergency communication. The term "amateur" is used to specify persons interested in radio technique solely with a personal aim , and to differentiate it from commercial broadcasting , public safety (such as police and fire), or professional two-way radio services (such as maritime, aviation, etc.). EE-494 Wireless Comm. by Dr. Ibrar 20

21. Most electronic communication is two-way and is referred to as duplex . When people can talk and listen simultaneously, it is called full duplex . The telephone is an example of this type of communication. Full Duplex EE-494 Wireless Comm. by Dr. Ibrar 21

22. COMMUNICATION SYSTEM ANALOG COMMUNICATION DIGITAL COMMUNICATION EE-494 Wireless Comm. by Dr. Ibrar 22

23. Analog Communication EE-494 Wireless Comm. by Dr. Ibrar 23

24. Digital Communication EE-494 Wireless Comm. by Dr. Ibrar 24

25. To be transmitted, data must be transformed to electromagnetic signals. Note EE-494 Wireless Comm. by Dr. Ibrar 25

26. Data can be analog or digital . The term analog data refers to information that is continuous. Digital data refers to information that has discrete states. Analog data take on continuous values. Digital data take on discrete values. Data EE-494 Wireless Comm. by Dr. Ibrar 26

27. Comparison of analog and digital signals EE-494 Wireless Comm. by Dr. Ibrar 27

28. Analog Signal Cycle Time Signal Amplitude Frequency = Cycles/Second A typical sine wave EE-494 Wireless Comm. by Dr. Ibrar 28

29. Analog Signal 3 Basic Parameters of analog signal Amplitude Frequency Phase EE-494 Wireless Comm. by Dr. Ibrar 29

30. Two signals with the same phase and frequency, but different amplitudes EE-494 Wireless Comm. by Dr. Ibrar 30

31. Frequency is the rate of change of cycle (Positive and Negative) with respect to time. Change in a short span of time means high frequency. Change over a long span of time means low frequency. Frequency EE-494 Wireless Comm. by Dr. Ibrar 31

32. If a signal does not change at all, its frequency is zero. If a signal changes instantaneously, its frequency is infinite. Note EE-494 Wireless Comm. by Dr. Ibrar 32

33. Two signals with the same amplitude and phase, but different frequencies EE-494 Wireless Comm. by Dr. Ibrar 33

34. 3 Sine waves with frequencies 0, 8 & 16 EE-494 Wireless Comm. by Dr. Ibrar 34

35. Phase Phase describes the position of the waveform relative to time 0. Note EE-494 Wireless Comm. by Dr. Ibrar 35

36. Three sine waves with the same amplitude and frequency, but different phases EE-494 Wireless Comm. by Dr. Ibrar 36

37. Units of period and frequency EE-494 Wireless Comm. by Dr. Ibrar 37

38. Composite Signal EE-494 Wireless Comm. by Dr. Ibrar 38

39. Available range of frequencies for communication Starts from low frequency communication such as voice and progresses to high frequency communication such as satellite communication The spectrum spans the entire bandwidth of communicable frequencies Frequency Spectrum EE-494 Wireless Comm. by Dr. Ibrar 39

40. Frequency Spectrum Low Frequency High Frequency Radio Frequency Coaxial Cable MHz Satellite Transmission Microwave GHz Voice KHz EE-494 Wireless Comm. by Dr. Ibrar 40

41. Bandwidth, in general, represents a range of frequencies Bandwidth Definition 300 MHz 700 MHz Bandwidth is 400 MHz EE-494 Wireless Comm. by Dr. Ibrar 41

42. The bandwidth of a composite signal is the difference between the highest and the lowest frequencies contained in that signal. Bandwidth and Signal Frequency EE-494 Wireless Comm. by Dr. Ibrar 42

43. Bandwidth is indicative of the communication capacity Communication speed is proportional to bandwidth Units used to represent bandwidth are Hz, bps etc. Communication Capacity EE-494 Wireless Comm. by Dr. Ibrar 43

44. The Electromagnetic Spectrum Figure: The electromagnetic spectrum. EE-494 Wireless Comm. by Dr. Ibrar 44

45. What is a Network ? What is a Computer Network ? What are the uses of a Computer network ? 45 Networks

46. Classification of Computer networks Based on the Direction of Data Flow Based on the Transmission Mode Based on time in Transmission type Based on Authentication Based on Scale and Geographical location Based on Reliability Based on The structure of the network / Topology 46

47. Classification of Computer networks Based on the direction of data flow 47

48. Classification of Computer networks 2. Based on the types of transmission 48

49. Classification of Computer networks 3. Based on the mode of transmission 49

50. Classification of Computer networks 4. Based on the authentication/relationship between the computers 50

51. 51 Client-server architecture server: always-on host permanent IP address data centers for scaling clients: communicate with server may be intermittently connected may have dynamic IP addresses do not communicate directly with each other client/server

52. 52 P2P architecture no always-on server arbitrary end systems directly communicate peers request service from other peers, provide service in return to other peers self scalability – new peers bring new service capacity, as well as new service demands peers are intermittently connected and change IP addresses complex management peer-peer

53. Classification of Computer networks 5. Based on the structure of the network or topology 53

54. 54 Figure 1.5 A fully connected mesh topology (five devices)

55. 18 Figure 1.8 A ring topology connecting six stations

56. 56 Figure 1.7 A bus topology connecting three stations

57. 57 Figure 1.6 A star topology connecting four stations

58. 58 Figure 1.9 A hybrid topology: a star backbone with three bus networks

59. Classification of Computer networks 6. Based on the scale of the network 59

60. Classification of Computer networks 6. Based on the reliability 60