A353 Fundamentals of Electronic Communications PDF

Republic of the Philippines Tarlac State University COLLEGE OF ENGINEERING AND TECHNOLOGY Department of Electrical and Electronics Engineering Tarlac City A353 – FUNDAMENTALS OF ELECTRONIC COMMUNICATIONS Prepa...

Republic of the Philippines Tarlac State University COLLEGE OF ENGINEERING AND TECHNOLOGY Department of Electrical and Electronics Engineering Tarlac City A353 – FUNDAMENTALS OF ELECTRONIC COMMUNICATIONS Prepared by: Idris Jeffrey M. Manguera June 2020 Fundamentals of Electronic Communications Chapter 1: Introduction to Communications Systems Intended Learning Outcomes 1. Define an electronic communication system. 2. Identify the basic elements and parameters of an electronic communication system. 3. Describe the different modes of transmission of electronic communications. Activities List down the differences between face-to-face verbal communication and virtual communication through electronic means. Processing Communication is defined as the basic process of exchanging information. Most humans communicate through spoken word but a considerable amount of communication is nonverbal. Consequently, the two major barriers in human communication are language and distance. Timeline of Milestones in Human and Electronic Communications Year Milestone 1830 Professor Joseph Henry transmitted the first practical signal. 1837 Samuel F.B. Morse invented the telegraph. 1876 Alexander Graham Bell and Thomas A. Watson invented the telephone. 1887 Heinrich Hertz discovered radio waves. Guglielmo Marconi demonstrated wireless radio wave propagation. 1901 Guglielmo Marconi accomplished the first transatlantic transmission of radio signals. 1903 John Fleming invented the two-electrode vacuum-tube rectifier. 1906 Lee De Forest invented the triode vacuum tube. 1923 Vladimir Zworykin invented and demonstrated television. 1948 William Shockley, Walter Brattain and John Bardeen invented the transistor. 1959 The integrated circuit was invented. 1965 The first commercial communications satellite was launched. 1983 The cellular telephone network was first introduced in the United States. Abstraction Electronic Communications Systems Electronic Communications refer to the transmission, reception and processing of information using electronic circuits. The basic elements of a communication system include the transmitter, the communications channel or medium, and the receiver. Course Code Course Title Date Effective: Rev. No. Prepared by: Page No.: A353 Fundamentals of Electronic Communications 1st Sem. S.Y. 2020-2021 00 I.J.M. Manguera 1 of 5 Fundamentals of Electronic Communications Chapter 1: Introduction to Communications Systems Sources of Information Sources of information may come from an analog source of from a digital source so that intelligence signals may either be in analog or digital. Analog signals continuously change with respect to time and has infinite amplitude values. Digital signals are discrete with amplitudes of finite value. Transmitter The transmitter is a collection of electronic devices or circuits designed to convert the information into a signal suitable for transmission over a given communications medium. The components of a transmitter are the amplifier, modulator, oscillator and antenna. Communications Channel or Medium The communications channel provides the means of transporting signals between a transmitter and a receiver. The two general types of communications media are guided (wired) and unguided (wireless). Examples of guided media are coaxial cable, fiber optic cable and waveguide. Although the medium supports the transmission of information, it also attenuates it and causes the received signal to appear much lower in amplitude. Considerable amplification of the signal is required for successful communication. Receiver Receiver is a collection of electronic devices or circuits that accept the transmitted message from the channel and convert them into a form understandable to humans. The components of a receiver are the amplifier demodulator and audio output device. Limitations of Communications Systems The two limitations in the electronic communication systems are noise and bandwidth. Noise is any unwanted form of energy that tends to interfere with the proper and easy reception and reproduction desired signals. Bandwidth is the portion of the electromagnetic spectrum occupied by a signal. It is also the frequency range over which an information signal is transmitted or over which a receiver or other electronic circuit operates. Specifically, the bandwidth is the difference between the upper and the lower frequency limit. 𝐵𝑊 = 𝑓!""#$ &'(') − 𝑓&*+#$ &'(') Information Capacity A measure of how much source information can be carried through the system in a given period of time. Hartley’s Law States that the information capacity is directly proportional to bandwidth and transmission time 𝐼𝑛𝑓𝑜𝑟𝑚𝑎𝑡𝑖𝑜𝑛 𝐶𝑎𝑝𝑎𝑐𝑖𝑡𝑦 ∝ 𝐵𝑎𝑛𝑑𝑤𝑖𝑑𝑡ℎ ∝ 𝑇𝑟𝑎𝑛𝑠𝑚𝑖𝑠𝑠𝑖𝑜𝑛 𝑇𝑖𝑚𝑒 Modes of Transmission Electronic Communications may be transmitted either one-way or two-way. One-way transmission is called simplex or broadcasting. Two-way communication is called duplex. In half- duplex transmission, only one of two parties can transmit at a time. In a full-duplex transmission, both parties may transmit and receive simultaneously. Course Code Course Title Date Effective: Rev. No. Prepared by: Page No.: A353 Fundamentals of Electronic Communications 1st Sem. S.Y. 2020-2021 00 I.J.M. Manguera 2 of 5 Fundamentals of Electronic Communications Chapter 1: Introduction to Communications Systems Simplex (SX) Examples: AM and FM Broadcasting, TV Broadcasting, Cable Television, Wireless Remote Control, Paging Services, Navigation and Direction-finding Services Half-duplex (HDX) Examples: Two-way radio, Amateur Radio, Citizen’s Band Radio, Radar, Sonar Full-duplex (FDX) Examples: Telephones, Data Communications, Local Area Networks Full/full duplex (F/FDX) transmits and receives simultaneously but not necessarily between the same two stations. Electromagnetic Spectrum The electromagnetic frequency spectrum refers to the entire range of usable frequencies. It extends from a few Hz to cosmic rays. Frequency Frequency is the number of times a periodic/repetitive signal goes through its complete cycle per second. The international unit of frequency is Hertz (Hz). Wavelength, l Wavelength is the length that one cycle of an electromagnetic wave occupies in space. The length of a wave depends on the frequency of the wave and the velocity of light. Mathematically, 𝑐 𝜆=𝑘 𝑓 Where: k = Velocity factor (equal to 1 in free space) c = speed of light in free space, 3x108 m/s f = Frequency, Hz At high frequencies, the wavelength is too short and is usually expressed as Angstrom 1 1 Å (𝐴𝑛𝑔𝑠𝑡𝑟𝑜𝑚) = 𝜇𝑚 1000 International Telecommunications Union (ITU) Band Designations Course Code Course Title Date Effective: Rev. No. Prepared by: Page No.: A353 Fundamentals of Electronic Communications 1st Sem. S.Y. 2020-2021 00 I.J.M. Manguera 3 of 5 Fundamentals of Electronic Communications Chapter 1: Introduction to Communications Systems Reading Assignment To further enhance knowledge on electronic communications and applications of the ITU Band Designations, you may read the first chapter of the book by Wayne L. Tomasi, Electronic Communications – Fundamentals through Advanced, 5th ed. Assessment Tasks Multiple Choice Questions 1. Light frequency below 400 microns is a. infrared b. visible light c. ultra-violet d. none of the above 2. In a given bandwidth, more channels are available for signals in the range of a. VHF b. SHF c. EHF d. UHF 3. Equipment that represents the signal in the frequency domain is the a. oscilloscope b. spectrum analyzer c. laparoscope d. function generator 4. A complete communication system should include: a. a transmitter, a receiver and a spectrum analyzer b. a multiplexer, a demultiplexer and a channel c. a transmitter and receiver d. a transmitter, a receiver and a channel 5. The bandwidth required for a modulated carrier depends on a. the signal-to-noise ratio b. the baseband frequency range c. the carrier frequency d. none of the above 6. The baseband bandwidth for a voice-grade (telephone) signal is a. at least 5 kHz b. 20 Hz to 15,000 Hz Course Code Course Title Date Effective: Rev. No. Prepared by: Page No.: A353 Fundamentals of Electronic Communications 1st Sem. S.Y. 2020-2021 00 I.J.M. Manguera 4 of 5 Fundamentals of Electronic Communications Chapter 1: Introduction to Communications Systems c. Approximately 3 kHz d. none of the above 7. A simultaneous two-way communication is called a. simplex b. full-full duplex c. full duplex d. half duplex 8. Recovering the originally transmitted signal is called a. modulation b. demodulation c. multiplexing d. diplexing 9. Short waves fall under a. ELF b. MF c. VHF d. HF 10. Microwaves start at a. UHF b. MF c. VHF d. SHF References: 1. Tomasi W. Electronic Communications Systems – Fundamentals through Advanced 5th Edition, New Jersey, Prentice Hall 2. Roddy J., Coolen E., Electronic Communications 5th Edition, New Jersey, Prentice Hall 3. Frenzel L., Principles of Electronic Communication Systems, New York, Mc Graw Hill Course Code Course Title Date Effective: Rev. No. Prepared by: Page No.: A353 Fundamentals of Electronic Communications 1st Sem. S.Y. 2020-2021 00 I.J.M. Manguera 5 of 5