Basics of Electronic Communication

Forms of Communication, Elements of Communication System

1. Chapter 1 BASICS OF ELECTRONICS COMMUNICATION 12 Marks 08 Hours Ms. Kavita Giri Lecturer ( ET) Government Residential Womens Polytechnic , Latur

2. Contents 1.1 The elements of basic electronic communication systems. 1.2 Electromagnetic spectrum – different bands and their applications. 1.3 Transmission modes – simplex, half duplex , full duplex Synchronous and Asynchronous 1.4 Sources of Noise 1.5 Definition of noise figure and SNR. 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

3. Learning Outcomes After completion of this chapter you should be able to: Define different terms related to electronic communication. Describe the functioning of communication system. Identify the various bands in the EM spectrum. Identify the various forms of electronic communication. Classify different types of noise based on its source. 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

4. 1.1 Introduction to electronic communication The word communication arises from the Latin word “ commūnicāre ”, which means ‘ to share ’. Communication is the basic step for the exchange of information . For example, a baby in a cradle, communicates with a cry that she needs her mother. A cow moos loudly when it is in danger. A person communicates with the help of a language. Communication is the bridge to share . 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

5. Communication  can be defined as the process of exchange of information through means such as words, actions, signs, etc., between two or more individuals. ….1.1 Introduction to electronic communication 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

6. For any living being, while co-existing, there occurs the necessity of exchange of some information. Whenever a need for exchange of information arises, some means of communication should exist. While the means of communication, can be anything such as gestures, signs, symbols, or a language, the need for communication is inevitable. Language and gestures play an important role in human communication, while sounds and actions are important for animal communication. However, when some message has to be conveyed, a communication has to be established. 1.1.2 Need for communication 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

7. 1.1.3 Elements of communication system Sender (Transmitter) Channel Receiver 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

8. 1.1.3 Elements of communication system 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

9. 1.2 Communication System Communication means sending, receiving and processing of information between two or more devices. Some examples of communication system include radio broadcasting, television broadcasting, radio telegraphy, mobile communication, computer communication etc. A collection of elements (devices) which works together to establish a communication between the sender and receiver is called a communication system. 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

10. ……1.2 Communication System Block Diagram of a Communication System 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

11. ……1.2 Communication System 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

12. ……1.2 Communication System 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

13. ……1.2 Communication System 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

14. 1.3 The Electromagnetic spectrum The process of signal travel from transmitter to receiver has been divided into two parts as: 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

15. 1.3 The Electromagnetic spectrum 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur Radiation Propagation

16. …..1.3 The Electromagnetic spectrum Electromagnetic waves (or radio waves) are nothing but oscillations which propagate in free space. They travel at the speed of light . These waves consists of moving fields of electric and magnetic forces , thus known as electromagnetic (EM) waves. The frequency of EM signal ranges from few Hz to several GHz. This entire range of frequencies of EM waves is called as Electromagnetic Spectrum . 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

17. …..1.3 The Electromagnetic spectrum 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

18. …..1.3 The Electromagnetic spectrum 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur https:// youtu.be/1JpwDaOHppA

19. …..1.3 The Electromagnetic spectrum 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

20. …..1.3 The Electromagnetic spectrum Sr. No. Frequency Band Applications 01 300 Hz to 3KHz Voice or audio communication (Used in telephone lines) 02 VLF – 3KHz to 30KHz Submarine, military, navy communication 03 LF – 30KHz to 300KHz Marine, Navigation, also used as subcarrier frequency 04 MF – 300KHz to 3MHz MW band of AM radio broadcast 05 HF- 3MHz to 30MHz SW i.e., short wave band of AM radio 06 VHF – 30MHz to 300MHz TV and FM radio broadcasting 07 UHF – 300MHz to 3GHz UHF TV channels, mobile phones 08 SHF – 3GHz to 30GHz Satellite and Radar 09 EHF – 30GHz to 300GHz Satellite and Radar 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

21. 1.4 Types of electronic communication 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

22. 1. In simplex mode the data transmits in one direction only, from one system to another system. 2. The sender device that sends data can only send data and cannot receive it. On the other hand the receiver device can only receive the data and cannot send it. 3. Television is an example of simplex mode transmission as the broadcast sends signals to our TV but never receives signals back from our TV. This is a unidirectional transmission. …..1.4 Types of electronic communication 1.4.1.1 Simplex Communication 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

23. …..1.4 Types of electronic communication 1.4.1.1 Simplex Communication Transmitter Receiver Channel 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

24. Advantages of Simplex Mode: The full capacity of the transmission medium is utilized as the transmission is one way and cannot have traffic issues. Disadvantages of Simplex Mode: No bidirectional communication is possible. Two devices cannot communicate with each other using simplex mode of transmission. …..1.4 Types of electronic communication 1.4.1.1 Simplex Communication 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

25. 1. In half duplex mode transmission can be done both ways which means if two systems are connected with half-duplex mode of transmission, they both can send and receive data but not at the same time. 2. If one device is sending data then other device cannot send data until it receives the data which is already in transmission. You can say that the communication is not simultaneous. 3. The radio communication device that our soldiers use at the battle fields are the examples of half duplex mode transmission as they send message and then say over and then the person on other hand send his message and this way they communicate but not simultaneously like we used to do on mobile. …..1.4 Types of electronic communication 1.4.1.2 Half Duplex Communication 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

26. …..1.4 Types of electronic communication 1.4.1.2 Half Duplex Communication Trans-Receiver1 Trans-Receiver2 Alpha!!! There is an emergency… Alpha come in… Delta Over. Delta!!! Message received. Just reporting… Alpha Over. Trans-Receiver1 Trans-Receiver2 Transmits Transmits Receives Receives 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

27. Advantages of Half-Duplex mode: Both devices can send and receive data. Whole bandwidth can be utilized as at a time only one signal transmits. Disadvantages of Half-Duplex mode: The disadvantage in half duplex mode is that the other device cannot send data until it receives the data which is already in transmission, this can cause delays to the communication. …..1.4 Types of electronic communication 1.4.1.2 Half Duplex Communication 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

28. 1. In full duplex mode both the connected devices can send and receive data simultaneously. The mobile phone we use is an example of full duplex mode where we can communicate simultaneously . 2. Both the devices can send and receive the data at the same time. …..1.4 Types of electronic communication 1.4.1.3 Full Duplex Communication 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

29. …..1.4 Types of electronic communication 1.4.1.3 Full Duplex Communication Transceiver A Transceiver B Channel 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

30. Advantages of Full Duplex mode: No delays in communication as both can send and receive data simultaneously. Disadvantages of Full Duplex mode: No proper bandwidth utilization as the same line is used for sending and receiving data at the same time. …..1.4 Types of electronic communication 1.4.1.3 Full Duplex Communication 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

31. An  analog communication system  is a communication system where the information signal sent from point A to point B can only be described as an analog signal. An example of this is Monica speaking to Carl over the telephone. …..1.4 Types of electronic communication 1.4.2.1 Analog Communication System Hello Carl… How are you?? 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

32. A  digital communication system  is a communication system where the information signal sent from A to B can be fully described as a digital signal. For example, Here, data is sent from one computer to another over a wire. The computer at point A is sending 0s or 1s to the computer at point B; 0 is being represented by −5 V for a duration of time  T  and a 1 is being represented by a +5 V for the same duration  T . Sent signal can be fully described using a digital signal. …..1.4 Types of electronic communication 1.4.2.2 Digital Communication                                                          1100110011 1100110011 A B 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

33. …..1.4 Types of electronic communication 1.4.3.1 Baseband Transmission                                                          The input signal to a communication system is either analog i.e., sound or picture or digital i.e., computer data. Sound or picture is converted into electrical signal. The electrical equivalent of the original information signal is known as the baseband signal. The communication system in which the baseband signals are transmitted directly is called as ‘Baseband Transmission’. 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

34. 1.5 Applications of Communication AM and FM radio broadcasting TV broadcasting Telemetry Cable TV systems FAX, Pager, Telephones Mobile Phones Radar 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

35. 1.8 Noise Noise is an unwanted signal which interferes with the original message signal and corrupts the parameters of the message signal. This alteration in the communication process, leads to the message getting altered. It is most likely to be entered at the channel or the receiver.  It is quite random and unpredictable. Measures are usually taken to reduce it, though it can’t be completely eliminated. Most common examples of noise are − Hiss sound in radio receivers Buzz sound amidst of telephone conversations Flicker in television receivers, etc. 1.8.1 What is Noise? 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

36. Noise limits the operating range of the systems Noise indirectly places a limit on the weakest signal that can be amplified by an amplifier. The oscillator in the mixer circuit may limit its frequency because of noise. A system’s operation depends on the operation of its circuits. Noise limits the smallest signal that a receiver is capable of processing. Noise affects the sensitivity of receivers Sensitivity is the minimum amount of input signal necessary to obtain the specified quality output. Noise affects the sensitivity of a receiver system, which eventually affects the output. ……1.8 Noise 1.8.2 Effects of Noise 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

37. ……1.8 Noise 1.8.3 Classification of Noise 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

38. ……1.8 Noise 1.8.3.1 External Noise This noise is produced by the external sources which may occur in the medium or channel of communication, usually. This noise cannot be completely eliminated. The best way is to avoid the noise from affecting the signal. T ypes of external noise are − Atmospheric noise Extra-terrestrial noise Industrial noise 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

39. ……1.8 Noise 1.8.3.1 External Noise 1. Atmospheric Noise Atmospheric noise or static is caused by lighting discharges in thunderstorms and other natural electrical disturbances occurring in the atmosphere. These electrical impulses are random in nature. Hence the energy is spread over the complete frequency spectrum used for radio communication. Atmospheric noise accordingly consists of spurious radio signals with components spread over a wide frequency range. It is propagated over the earth in the same way as the desired radio waves of the same frequencies, so that a given receiving point, the receiving antenna picks up not only the signal but also the static from all the thunderstorms, local or remote. 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

40. ……1.8 Noise 1.8.3.1 External Noise 2. Extra-terrestrial Noise Solar Noise: This is the electrical noise emanating from the sun. Under quite conditions, there is a steady radiation of noise from the sun. This results because sun is a large body at a very high temperature (exceeding 6000°C on the surface), and radiates electrical energy in the form of noise over a very wide frequency spectrum including the spectrum used for radio communication. The intensity produced by the sun varies with time. In fact, the sun has a repeating 11-Year noise cycle. During the peak of the cycle, the sun produces some amount of noise that causes tremendous radio signal interference, making many frequencies unusable for communications. 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

41. ……1.8 Noise 1.8.3.1 External Noise 2. Extra-terrestrial Noise B) Cosmic Noise: Distant stars are also suns and have high temperatures. These stars, therefore, radiate noise in the same way as our sun. The noise received from these distant stars is thermal noise (or black body noise) and is distributing almost uniformly over the entire sky. We also receive noise from the center of our own galaxy (The Milky Way) from other distant galaxies and from other virtual point sources such as quasars and pulsars. 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

42. ……1.8 Noise 1.8.3.1 External Noise 3. Industrial Noise It is the electrical noise produced by such sources as automobiles and aircraft ignition, electrical motors and switch gears, leakage from high voltage lines, fluorescent lights, and numerous other heavy electrical machines. Such noises are produced by the arc discharge taking place during operation of these machines. Such man-made noise is most intensive in industrial and densely populated areas. Man-made noise in such areas far exceeds all other sources of noise in the frequency range extending from about 1 MHz to 600 MHz 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

43. ……1.8 Noise 1.8.3.2 Internal Noise This noise is produced by the receiver components while functioning. The components in the circuits, due to continuous functioning, may produce few types of noise. This noise is quantifiable. A proper receiver design may lower the effect of this internal noise. T ypes of internal noise are − Thermal Noise Shot Noise Transit time Noise Miscellaneous Noise 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

44. ……1.8 Noise 1.8.3.2 Internal Noise 1. Thermal Noise (Johnson noise or White noise) Conductors contain a large number of free electrons and ions strongly bound by molecular forces. The ions vibrate randomly about their normal (average) positions, however, this vibration being a function of the temperature. Continuous collisions between the electrons and the vibrating ions take place. Thus there is a continuous transfer of energy between the ions and electrons. This is the source of resistance in a conductor. The movement of free electrons constitutes a current which is purely random in nature and over a long time averages zero. There is a random motion of the electrons which give rise to noise voltage called thermal noise. 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

45. ……1.8 Noise 1.8.3.2 Internal Noise 2. Shot Noise Shot noise is produced by the random movement of electrons or holes across a PN junction. Even through current flow is established by external bias voltages, there will still be some random movement of electrons or holes due to discontinuities in the device. An example of such a discontinuity is the contact between the copper lead and the semiconductor materials. The interface between the two creates a discontinuity that causes random movement of the current carriers. 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

46. ……1.8 Noise 1.8.3.2 Internal Noise 3. Transit time Noise Transit time is the duration of time that it takes for a current carrier such as a hole or current to move from the input to the output. The devices themselves are very tiny, so the distances involved are minimal. Yet the time it takes for the current carriers to move even a short distance is finite. At low frequencies this time is negligible. But when the frequency of operation is high and the signal being processed is the magnitude as the transit time, then problem can occur. The transit time shows up as a kind of random noise within the device, and this is directly proportional to the frequency of operation. 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

47. ……1.8 Noise 1.8.3.2 Internal Noise 4. Miscellaneous Noise Flicker noise or modulation noise It is the one appearing in transistors operating at low audio frequencies. Flicker noise is proportional to the emitter current and junction temperature. However, this noise is inversely proportional to the frequency. Hence it may be neglected at frequencies above about 500 Hz and it, Therefore, possess no serious problem. Partition noise It occurs whenever current has to divide between two or more paths, and results from the random fluctuations in the division. It would be expected, therefore, that a diode would be less noisy than a transistor (all other factors being equal) If the third electrode draws current (i.e.., the base current). It is for this reason that the inputs of microwave receivers are often taken directly to diode mixers. 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur

48. 1.9 Signal to Noise Ratio & Noise Figure Signal to Noise Ratio Signal-to-Noise Ratio (SNR)  is the  ratio of the signal power to the noise power . The higher the value of SNR, the greater will be the quality of the received output. Noise Figure The ratio of  output SNR to the input SNR  can be termed as the  Noise Figure . It is denoted by  F . It describes the performance of a device. 22334 – Principles of Electronic Communication Ms. Kavita Giri , Lecturer (ET), Govt. Residential Womens Polytechnic, Latur