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1 ACS_Introduction.pdf

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This document provides information about the Analog Communication Systems course ECE3001 taught by Prof. Dr. G. Aarthi. The 3-credit theory course covers topics including linear modulation, angle modulation, pulse modulation systems, and receivers. Specific techniques that will be studied are AM, FM, sampling, PAM, PWM, PPM, FDM, and TDM. The objectives are to understand the design, analysis and applications of modulation/demodulation systems and to be able to analyze and design various communication system components. Assessment includes exams, assignments, quizzes and a final test.

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Analog Communication Systems- ECE3001 Prof. Dr. G.Aarthi, Associate Professor, SENSE Cabin: TT-132 Email: aarthi.g@vit.ac.in
General Course Information Prerequisite: Analog Electronic circuits, Signals and systems. Theory - 3 credits- 3 Hours per week Totally 45 Hours Lab 1 credit- 2 Hours per week
Course Objectives: To impart students the need, design, analysis and applications of Linear AM modulators and demodulators. To introduce and describe the Angle Modulation, demodulation and the concept of pre-emphasis and de-emphasis. To elaborate the super-heterodyne receiver and the Figure of Merit in DSB-SC, SSB, AM and FM receivers. To describe the sampling, pulse modulation schemes-PAM, PWM and PPM and the multiplexing techniques FDM and TDM.
Expected Course Outcome: Able to comprehend the elements of electronic communication system. Able to design AM, DSB-SC and SSB-SC modulation and demodulation, and to calculate the power of AM, DSB-SC and SSB-SC schemes. Able to design DSB-SC and SSB-SC modulator and demodulator. Comprehend and compare the FM and PM generation and design, distinguish Wideband and Narrowband FM signals. Comprehend and compare different angle demodulators. Able to design radio receivers, identify role of AGC, and compute noise voltage, signal-to-noise ratio, noise figure, noise temperature and figure of merit. Determine the Nyquist sampling rate of a given signal, explain aliasing effect, Comprehend and compare the different pulse modulation techniques.
Module:1 Introduction to Communication Systems: Need and Importance of Communication Elements of a Communication System Types of communication systems Electromagnetic Spectrum used in communication. Concept of bandwidth and power Receiver characteristics Need for modulation
Module:2 Linear Modulation : Amplitude modulation Frequency spectrum of AM Power in AM wave Generation of AM signal Square law modulator Switching modulator AM demodulation Envelope and square law demodulation.
Module:3 Bandwidth and Power Efficient AM Systems : DSB-SC modulation Power saving in DSB-SC Synchronous detection Quadrature null effect. SSB-SC VSB generation and demodulation Comparison of linear modulation systems with respect to power, bandwidth and receiver complexity Low level and high level AM transmitters
Module:4 Angle Modulation: Principle of frequency and phase modulation Relation between FM and PM waves Frequency deviation Bandwidth of FM Narrow band and wide band FM FM transmitter Bessel functions and Carsons rule Generation of FM and PM wave Comparison of AM and FM.
Module:5 Demodulation of Angle Modulated Signals: FM detectors Slope detectors Phase discriminators Ratio detectors. Feedback Demodulators The Phase Locked Loop Frequency Compressive Feedback Demodulator. Pre-emphasis and de-emphasis.
Module:6 Receivers and Noise in Communication Systems: Tuned Radio Frequency (TRF) Super-heterodyne receiver(AM and FM) Choice of IF and Oscillator frequencies Tracking alignment AGC AFC Noise and its types Noise voltage - Signal-to-noise ratio Noise figure - Noise temperature Figure of Merit in DSB-SC, SSB, AM and FM receivers
Module:7 Pulse Modulation Systems: Sampling theorem Types of Sampling Pulse modulation schemes PAM, PPM and PWM generation and detection Pulse code modulation Conversion of PWM to PPM Multiplexing Techniques - FDM and TDM Problems related to FDM and TDM
Module:8 Contemporary Issues
Text/Reference Books:
Course Rubrics(Theory) Continuous Assessment Test I (CAT-I) -15 Marks Continuous Assessment Test II (CAT-II) - 15 Marks Digital Assignment-1 - 10 Marks Quiz-1- 10 Marks Quiz-2- 10 Marks Final Assessment Test (FAT) - 40 Marks
Module 1 Introduction to Communication systems
Communication System A B Engineering System Genetic System Social System History and fact of communication
What is a communications system? Communications Systems: Systems designed to transmit and receive information Info Source Info Sink Comm System
Basic Communication system
History of Communications
1 ACS_Introduction.pdf
Communication system Block Diagram
Input Transducer
Transmitter
Channel
Communication Channels
1 ACS_Introduction.pdf
1 ACS_Introduction.pdf
Receiver
Output Transducer
Transceivers A transceiver is an electronic unit that incorporates circuits that both send and receive signals. Examples are: Telephones Fax machines Handheld CB radios Cell phones Computer modems
Attenuation & Noise Signal attenuation, or degradation, exists in all media of wireless transmission. It is proportional to the square of the distance between the transmitter and receiver. Noise is random, undesirable electronic energy that enters the communication system via the communicating medium and interferes with the transmitted message.
Types of Communication systems
Types of Electronic Communication Electronic communications are classified according to whether they are 1. One-way (simplex) or two-way (full duplex or half duplex) transmissions 2. Analog or digital signals.
Simplex The simplest method of electronic communication is referred to as simplex. This type of communication is one-way. Examples are: Radio TV broadcasting Beeper (personal receiver)
Full Duplex 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.
Half Duplex The form of two-way communication in which only one party transmits at a time is known as half duplex. Examples are: Police, military, etc. radio transmissions Citizen band (CB) Family radio Amateur radio
1 ACS_Introduction.pdf
Types of Electronic Communication Analog Signals An analog signal is a smoothly and continuously varying voltage or current. Examples are: Sine wave Voice Video (TV)
Analog Signals Analog signals (a) Sine wave tone. (b) Voice. (c) Video (TV) signal.
Types of Electronic Communication Digital Signals Digital signals change in steps or in discrete increments. Most digital signals use binary or two-state codes. Examples are: Telegraph (Morse code) Continuous wave (CW) code Serial binary code (used in computers)
Digital Signals Figure 1-6: Digital signals (a) Telegraph (Morse code). (b) Continuous-wave (CW) code. (c) Serial binary code.
1 ACS_Introduction.pdf
1 ACS_Introduction.pdf
1 ACS_Introduction.pdf
Electromagnetic spectrum
1 ACS_Introduction.pdf
1 ACS_Introduction.pdf
Electromagnetic spectrum
Concept of Bandwidth and Power in Communications
Power(dBW and dBm)
Receiver Characteristics
Modulation
Modulation
Modulation
1 ACS_Introduction.pdf
Need for Modulation Reduction in the height of antenna Multiplexing is possible Avoids mixing of signals Increases the range of communication Improves quality of reception
Reduction in the height of antenna
Reduction in the height of antenna
Multiplexing-Sharing a Medium
Multiplexing-Sharing a Medium
Multiplexing-Sharing a Medium
Avoids mixing of signals If the baseband sound signals are transmitted without using the modulation by more than one transmitter, then all the signals will be in the same frequency range i.e. 0 to 20 kHz . Therefore, all the signals get mixed together and a receiver can not separate them from each other . Hence, if each baseband sound signal is used to modulate a different carrier then they will occupy different slots in the frequency domain (different channels). Thus, modulation avoids mixing of signals .
Improves Quality of Reception With frequency modulation (FM) and the digital communication techniques such as PCM, the effect of noise is reduced to a great extent . This improves quality of reception

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1 ACS_Introduction.pdf

  • 1. Analog Communication Systems- ECE3001 Prof. Dr. G.Aarthi, Associate Professor, SENSE Cabin: TT-132 Email: aarthi.g@vit.ac.in
  • 2. General Course Information Prerequisite: Analog Electronic circuits, Signals and systems. Theory - 3 credits- 3 Hours per week Totally 45 Hours Lab 1 credit- 2 Hours per week
  • 3. Course Objectives: To impart students the need, design, analysis and applications of Linear AM modulators and demodulators. To introduce and describe the Angle Modulation, demodulation and the concept of pre-emphasis and de-emphasis. To elaborate the super-heterodyne receiver and the Figure of Merit in DSB-SC, SSB, AM and FM receivers. To describe the sampling, pulse modulation schemes-PAM, PWM and PPM and the multiplexing techniques FDM and TDM.
  • 4. Expected Course Outcome: Able to comprehend the elements of electronic communication system. Able to design AM, DSB-SC and SSB-SC modulation and demodulation, and to calculate the power of AM, DSB-SC and SSB-SC schemes. Able to design DSB-SC and SSB-SC modulator and demodulator. Comprehend and compare the FM and PM generation and design, distinguish Wideband and Narrowband FM signals. Comprehend and compare different angle demodulators. Able to design radio receivers, identify role of AGC, and compute noise voltage, signal-to-noise ratio, noise figure, noise temperature and figure of merit. Determine the Nyquist sampling rate of a given signal, explain aliasing effect, Comprehend and compare the different pulse modulation techniques.
  • 5. Module:1 Introduction to Communication Systems: Need and Importance of Communication Elements of a Communication System Types of communication systems Electromagnetic Spectrum used in communication. Concept of bandwidth and power Receiver characteristics Need for modulation
  • 6. Module:2 Linear Modulation : Amplitude modulation Frequency spectrum of AM Power in AM wave Generation of AM signal Square law modulator Switching modulator AM demodulation Envelope and square law demodulation.
  • 7. Module:3 Bandwidth and Power Efficient AM Systems : DSB-SC modulation Power saving in DSB-SC Synchronous detection Quadrature null effect. SSB-SC VSB generation and demodulation Comparison of linear modulation systems with respect to power, bandwidth and receiver complexity Low level and high level AM transmitters
  • 8. Module:4 Angle Modulation: Principle of frequency and phase modulation Relation between FM and PM waves Frequency deviation Bandwidth of FM Narrow band and wide band FM FM transmitter Bessel functions and Carsons rule Generation of FM and PM wave Comparison of AM and FM.
  • 9. Module:5 Demodulation of Angle Modulated Signals: FM detectors Slope detectors Phase discriminators Ratio detectors. Feedback Demodulators The Phase Locked Loop Frequency Compressive Feedback Demodulator. Pre-emphasis and de-emphasis.
  • 10. Module:6 Receivers and Noise in Communication Systems: Tuned Radio Frequency (TRF) Super-heterodyne receiver(AM and FM) Choice of IF and Oscillator frequencies Tracking alignment AGC AFC Noise and its types Noise voltage - Signal-to-noise ratio Noise figure - Noise temperature Figure of Merit in DSB-SC, SSB, AM and FM receivers
  • 11. Module:7 Pulse Modulation Systems: Sampling theorem Types of Sampling Pulse modulation schemes PAM, PPM and PWM generation and detection Pulse code modulation Conversion of PWM to PPM Multiplexing Techniques - FDM and TDM Problems related to FDM and TDM
  • 14. Course Rubrics(Theory) Continuous Assessment Test I (CAT-I) -15 Marks Continuous Assessment Test II (CAT-II) - 15 Marks Digital Assignment-1 - 10 Marks Quiz-1- 10 Marks Quiz-2- 10 Marks Final Assessment Test (FAT) - 40 Marks
  • 16. Communication System A B Engineering System Genetic System Social System History and fact of communication
  • 17. What is a communications system? Communications Systems: Systems designed to transmit and receive information Info Source Info Sink Comm System
  • 30. Transceivers A transceiver is an electronic unit that incorporates circuits that both send and receive signals. Examples are: Telephones Fax machines Handheld CB radios Cell phones Computer modems
  • 31. Attenuation & Noise Signal attenuation, or degradation, exists in all media of wireless transmission. It is proportional to the square of the distance between the transmitter and receiver. Noise is random, undesirable electronic energy that enters the communication system via the communicating medium and interferes with the transmitted message.
  • 33. Types of Electronic Communication Electronic communications are classified according to whether they are 1. One-way (simplex) or two-way (full duplex or half duplex) transmissions 2. Analog or digital signals.
  • 34. Simplex The simplest method of electronic communication is referred to as simplex. This type of communication is one-way. Examples are: Radio TV broadcasting Beeper (personal receiver)
  • 35. Full Duplex 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.
  • 36. Half Duplex The form of two-way communication in which only one party transmits at a time is known as half duplex. Examples are: Police, military, etc. radio transmissions Citizen band (CB) Family radio Amateur radio
  • 38. Types of Electronic Communication Analog Signals An analog signal is a smoothly and continuously varying voltage or current. Examples are: Sine wave Voice Video (TV)
  • 39. Analog Signals Analog signals (a) Sine wave tone. (b) Voice. (c) Video (TV) signal.
  • 40. Types of Electronic Communication Digital Signals Digital signals change in steps or in discrete increments. Most digital signals use binary or two-state codes. Examples are: Telegraph (Morse code) Continuous wave (CW) code Serial binary code (used in computers)
  • 41. Digital Signals Figure 1-6: Digital signals (a) Telegraph (Morse code). (b) Continuous-wave (CW) code. (c) Serial binary code.
  • 49. Concept of Bandwidth and Power in Communications
  • 56. Need for Modulation Reduction in the height of antenna Multiplexing is possible Avoids mixing of signals Increases the range of communication Improves quality of reception
  • 57. Reduction in the height of antenna
  • 58. Reduction in the height of antenna
  • 62. Avoids mixing of signals If the baseband sound signals are transmitted without using the modulation by more than one transmitter, then all the signals will be in the same frequency range i.e. 0 to 20 kHz . Therefore, all the signals get mixed together and a receiver can not separate them from each other . Hence, if each baseband sound signal is used to modulate a different carrier then they will occupy different slots in the frequency domain (different channels). Thus, modulation avoids mixing of signals .
  • 63. Improves Quality of Reception With frequency modulation (FM) and the digital communication techniques such as PCM, the effect of noise is reduced to a great extent . This improves quality of reception