1. ELECTRONICS COMMUNICATIONS(EKT313) Introduction By:Cik Junita Mohd Nordin 049798419/0133910593 School:PPKKP, Aras 2,Blok A, Kompleks Pengajian KUKUM

2. EKT313 Sem: 1 2006/2007  Meeting: Lecture 3 Hours, Lab 2 Hours  Tuesdays: 12-2pm; 4-6 pm (labs)  Thursdays: 3-4pm  Attendance are compulsory!!

3. SYNOPSIS  OBJECTIVES: To introduce and familiarized the students to electronics elements, components and circuits used in RF communications. At the end of the course, student would also be able to design and analyze the RF communication circuits.

4. SYNOPSIS TOPICS COVERED ARE: - Introductions to Electronics Communications, AM& SSB Modulations, AM Circuits, FM and FM Circuits, Radio Transmitter and Communications Receivers

5. ASSESSMENTS Final exam = 50% Test 1 = 10% Assignments/quizzes=5% Lab = 35% presentation ReportProject

6. LECTURE 1 REVIEW TO COMMUNICATION SYSTEMS PART 1

7. WHAT DO YOU UNDERSTAND of COMMUNICATION SYSTEM?

8. DEFINITIONS OF COMMUNICATIONS Humans exchanging information Machines exchanging information Conveying thoughts, feelings, ideas, and facts Sending and receiving information by electronic means

9. BARRIERS TO COMMUNICATIONS Language: human, computer, or electronic Distance: space between sending and receiving parties

10. COMMON FORMS OF COMMUNICATIONS Human voice: face-to-face conversations, public speakers, actors in plays, etc. Audio: CDs, tape, records, radio Body language: non-verbal Print: newspapers, magazines, books, etc. Film: still and movie Video: movies, graphics and animation Music: personal, concerts

11. FORMS OF ELECTRONIC COMMUNICATIONS Radio and TV broadcasting Telephone, wired and wireless Fax Pagers Computer networks: modem, e- mail, Internet and World Wide Web, wireless Satellites, radar, radio telescopes

12. KEY MILESTONES IN ELECTRONIC COMMUNICATIONS 1844Telegraph 1876Telephone 1895Radio 1923TV 1943Radar 1946Computers 1962Satellites 1989Internet

14. MODEL OF ALL COMMUNICATIONS SYSTEMS TXRX Noise Communications medium Information to be transmitted Received information Transmitter Receiver Channel

15. TYPES OF COMMUNICATIONS TXRX TX RX Simplex: One-way Duplex: Two-way Half duplex: Alternate TX/RX Full duplex: Simultaneous TX/RX Channel Channel(s)

16. TYPES OF COMMUNICATIONS SIGNALS Analog - smooth and continuous voltage variation. Digital - binary or two voltage levels. Time

17. COMMUNICATIONS SIGNAL VARIATIONS Baseband - The original information signal such as audio, video, or computer data. Can be analog or digital. Broadband - The baseband signal modulates or modifies a carrier signal, which is usually a sine wave at a frequency much higher than the baseband signal.

18. MODULATION An electronic technique in which a baseband information signal modifies a carrier signal (usually a sine wave) for the purpose of frequency translation and carrying the information signal via radio. The common types of modulation are amplitude, frequency and phase.

19. AMPLITUDE MODULATION High-frequency carrier The modulating (baseband) signal is a sinusoid in this example.

20. An AM signal as it usually appears on an oscilloscope The carrier frequency is normally much higher than the baseband frequency.

21. FREQUENCY MODULATION The baseband signal controls the carrier’s frequency and the carrier’s amplitude remains constant.

22. Resting f c Increasing f c Decreasing f c Resting f c Modulating signal Carrier FM

23. MULTIPLEXING Multiplexing (MUX or MPX) - the process of simultaneously transmitting two or more baseband information signals over a single communications channel. Demultiplexing (DEMUX or DMPX) - the process of recovering the individual baseband signals from the multiplexed signal.

24. MULTIPLEXING AND DEMULTIPLEXING MUXDEMUX Single communications channel (radio or cable) Original baseband information signals Recovered baseband information signals

25. ELECTRONIC COMMUNICATIONS APPLICATIONS Radio broadcasting (AM & FM) Television broadcasting (analog & DTV) Cable TV Wireless remote control Paging Navigation and direction finding Telemetry

26. ELECTRONIC COMMUNICATIONS APPLICATIONS (Continued) Radio astronomy Surveillance RF identification (ID) Music services Telephones (wired, cordless, cellular) Facsimile Two-way radio

27. ELECTRONIC COMMUNICATIONS APPLICATIONS (Continued) Radar Sonar Amateur radio Citizens and family radio Data communications Networks Internet and World Wide Web

28. FREQUENCY AND WAVELENGTH Cycle - One complete occurrence of a repeating wave (periodic signal) such as one positive and one negative alternation of a sine wave. Frequency - the number of cycles of a signal that occur in one second. Period - the time distance between two similar points on a periodic wave. Wavelength - the distance traveled by an electromagnetic (radio) wave during one period.

29. One cycle time PERIOD AND FREQUENCY COMPARED Frequency = f = 1/T T = One period

30. + 0time distance Frequency and wavelength compared f = 1/T T

31. CALCULATING WAVELENGTH AND FREQUENCY = wavelength in meters f = frequency in MHz = 300/f f = 300/

32. ELF 10 3 m 10 7 m 10 4 m10 5 m10 6 m10 m 1 m 10 -1 m10 -2 m10 -3 m10 -4 m 10 2 m 300 Hz 30 Hz 30 kHz 3 kHz 300 kHz30 MHz 3 MHz 300 MHz 3 GHz 300 GHz 30 GHz THE ELECTROMAGNETIC SPECTRUM FROM 30 HZ TO 300 GHZ UHFVHFHFMFLFVLF VF SHFEHF Frequency Wavelength Millimeter waves ( = 300/f) (f = 300/ )

33. LOW AND MEDIUM FREQUENCIES Extremely Low Frequencies - 30 to 300 Hz Voice Frequencies - 300 to 3000 Hz Very Low Frequencies - 3 kHz to 30 kHz Low Frequencies - 30 kHz to 300 kHz Medium Frequencies - 300 kHz to 3 MHz

34. HIGH FREQUENCIES High Frequencies - 3 MHz to 30 MHz Very High Frequencies - 30 MHz to 300 MHz Ultra High Frequencies - 300 MHz to 3 GHz (1 GHz and above = microwaves) Super High Frequencies - 3 GHz to 30 GHz Extremely High Frequencies - 30 GHz to 300 GHz

35. 10 -3 m10 -4 m 300 GHz Millimeter waves THE ELECTROMAGNETIC SPECTRUM ABOVE 300 GHZ Wavelength 0.8 x 10 -6 m 0.4 x 10 -6 m Infrared Visible Ultraviolet X-rays Gamma raysCosmic rays 10 -5 m

36. OPTICAL FREQUENCIES Infrared - 0.7 to 10 micron Visible light - 0.4 to 0.8 micron Ultraviolet - Shorter than 0.4 micron Note: A micron is one millionth of a meter. Light waves are measured and expressed in wavelength rather than frequency.

37. Noise, interference and distortion Noise:unwanted signals that coincide with the desired signals. Noise is random, undesirable electric energy. Two type of noise:internal and external noise. Internal noise: Caused by internal devices/components in the circuits. External noise:noise that is generated outside the circuit. Eg: atmospheric noise,solar noise, cosmic noise, man made noise. Interference-one type of external noise Distortion: signal being distorted

38. Limitations in communication system Physical constraint -Delay, attenuation, bandwidth limitation, etc Technological constraint - hardware. - Expertise - economy, law

39. Frequency Spectrum &Bandwidth The frequency spectrum of a waveform consists of all frequencies contained in the waveform and their amplitudes plotted in the frequency domain. The bandwidth of a frequency spectrum is the range of of frequencies contained in the spectrum.It is calculated by subtracting the lowest frequency from the highest.

40. Frequency Spectrum &Bandwidth (cont’d) Bandwidth of the information signal equals to the difference between the highest and lowest frequency contained in the signal. Similarly, bandwidth of communication channel is the difference between the highest and lowest frequency that the channel allow to pass through it