Contents

• 1. Introduction

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  Objectives, Introduction, The Communication System, Classification of Communication, Line Communication, Wireless or Radio Communication, The Modulation-Demodulation, Types of Modulation, Need for Modulation, Analog and Digital Signals, Conversion of Analog Signals into Digital Signals, The Sampling Theorem, Analog and Digital Communication, Analog Communication, Digital Communication, Need of Digital Communication, Effect of Noise, Distance to be Covered, Service Provided, Comparison of Analog and Digital Communication System, Limitations of Communication System, Noise Limitation, Bandwidth Limitation, Equipment Limitation, Introduction to Signals, Continuous-Time and Discrete-Time Signals, Analog and Digital Signals, Periodic and Aperiodic Signals, Energy and Power Signals, Deterministic and Random Signals, Fourier Series, Trigonometric Fourier Series, Exponential form of the Fourier Series, Normalized Power, Power Spectral Density, Effect of Transfer Function on Power Spectral Density, The Fourier Transform, Convolution, Autocorrelation, Summary, Review Questions, Multiple Choice Questions, Answer Key.
   
  2. Noise Effects in Communication Systems

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  Objectives, Introduction, Representation of Band-limited and Band Pass Process, Band Limited Process, Band Pass Process, Noise Sources and Classification, External Noise, Atmospheric Noise, Extraterrestrial Noise, Industrial Noise, Internal Noise, Shot Noise, Partition Noise, Low Frequency or Flicker Noise, High Frequency or Transit-time Noise, Thermal Noise (Resistor Noise), Noise in Reactive Circuits, Signal to Noise Ratio, Noise Figure, Calculation of Noise Figure, Noise Figure from Equivalent Noise Resistance, Noise figure from Measurement, Noise Figure in Terms of S/N Ratio, Noise Temperature, Cascaded States, Noise Figure of Cascaded Amplifiers, Equivalent Noise Temperature of Cascaded Stages, Noise Bandwidth, Solved Problems, Summary, Short Questions Answers, Review Questions, Answer Key, Numerical Problems, Multiple Choice Questions, Answer Key.
   
  3. Amplitude Modulation

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  Objectives, Introduction, Frequency Translation, Frequency Multiplexing, Practicability of Antennas, Narrowbanding, Common Processing, A Method of Frequency Translation, Recovery of the Baseband Signal, Amplitude Modulation, Time Domain Representation, Spectrum of AM Signal, Single Tone Sinusoidal Modulation, Power Content in AM Wave, Transmission Efficiency of an AM Signal, Power of a Single tone AM Signal, Current Calculation for Single Tone AM, Multitone Sinusoidal Modulation, Power Content in Multitone Sinusoidal Modulation, Effective Modulation Index for Multitone Sinusoidal Modulation, Generation of Amplitude Modulated Wave, Square Law Modulator, Switching Modulator, Demodulation (Detection) of AM Wave, Square-Law Demodulation, Envelope Detector, Suppressed Carrier Modulation, Double-Sideband Suppressed Carrier (DSB-SC) Modulation, Generation of DSB-SC Waves, Balanced Modulator, Ring Modulator, Demodulation of DSB-SC Signals, Synchronous Detector, Effect of Phase and Frequency Error in Synchronous Detection, Envelope Detector After Suitable Carrier Reinsertion, Hilbert Transform, Single-Sideband Suppressed Carrier (SSB-SC) Modulation, Frequency Domain Description, Time Domain Description, Generation of SSB-SC Signals, Frequency Discrimination Method, Phase-Shift Method, Demodulation of SSB-SC Signal, Synchronous or Coherent Detection, Carrier Re-Insertion Technique, AM Transmitter and Receivers, AM Transmitter, AM Receiver, Single Sideband Transmission and Reception, SSB Transmitter, Pilot Carrier Transmitter, ISB Transmitter, SSB Receiver, Reinserted Carrier, Characteristics of AM Receivers, Sensitivity, Selectivity, Image Frequency and its Rejection, Double Spotting, Superheterodyne Receiver, RF Section, Frequency Changing and Tracking, Local Oscillator, Intermediate Frequencies and IF Amplifiers, Automatic Gain Control (AGC), Vestigial Sideband (VSB) Modulation, Solved Problems, Summary, Short Questions with Answers, Review Questions, Answer Key, Unsolved Problems, Multiple Choice Questions, Answer Key.
   
  4. Frequency Modulation

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  Objectives, Introduction, Concept of Instantaneous Frequency, Mathematical Representation of Frequency and Phase Modulation, Phase Modulation (PM), Frequency Modulation (FM), Relationship Between Phase Modulation and Frequency Modulation, Single-Tone Frequency Modulation, Types of Frequency Modulation, Narrow-Band Frequency Modulation (NBFM), Wide Band Frequency Modulation (WBFM), Spectrum of FM, Effect of the Amplitude and Frequency of a Sinusoidal Modulating Signal on the Spectrum of the FM Signal, Transmission Bandwidth of FM Signals, Power Contents of Carrier and Sidebands in FM, FM Generation, Direct Method of Generation of FM, Indirect Method of Generation of FM (Armstrong’s Method), FM Demodulation, Basic Principle, Types of FM Demodulators, Simple Slope Detector, Balanced Slope Detector, Foster-seeley Discriminator or Centre Tuned Discriminator or Phase Difference Discriminator, Ratio Detector, FM Transmitters, Automatic Frequency Correction (AFC), Direct FM Transmitters, FM Receiver, Advantages of FM, Disadvantages of FM, Comparison of Angle Modulated Waves and Amplitude Modulated Wave, Comparison of FM and AM, Effect of Channel Non-Linearity, Noise in FM Receivers, Solved Problems, Summary, Short Questions with Answers, Review Questions, Answer Key, Unsolved Problems, Multiple Choice Questions, Answer Key.
   
  5. Noise in AM and FM

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  Objectives, Introduction, Noise in Communication system, Assumptions to Calculate the Figure of Merit for Various Communication Systems, Noise in CW Modulation Systems, Signal-to-Noise Ratios, Calculation of Noise in Various Amplitude Modulation Systems, Signal Sideband Suppressed Carrier (SSB-SC), Calculation of Signal Power, Calculation of Noise Power, Quadrature Noise Components, Calculation of Signal-to-Noise Ratio (SNR), Double Sideband Suppressed Carrier (DSB-SC), Calculation of Noise Power, Calculation of Signal Power, Calculation of Signal-to-Noise Ratio, Quadrature Noise Components to Calculate N0, Arbitrary Modulating Signal, Double Sideband with Carrier (DSB-C), Noise Calculation of Square-law Demodulator, Noise Calculation of Envelope Detector, Noise in Frequency Modulation Systems, FM Receiving System, Output Signal Power, Output Noise Power, Output Signal-to-Noise Ratio, Comparison of FM and AM, Noise in Phase Modulation, Pre-Emphasis and De-Emphasis in FM, Threshold Effect, Solved Problems, Summary, Short Questions with Answers, Review Questions, Answer Key, Unsolved Problems, Multiple Choice Questions, Answer Key.
   
  6. Pulse Analog Modulation

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  Objectives, Introduction, Sampling Theorem, Proof of Sampling Theorem, Nyquist Rate and Nyquist Interval, Aliasing, Natural Sampling, Flat-Top Sampling, Reconstruction Filter (Low pass Flitter), Signal Reconstruction: The Interpolation Formula, Pulse-Amplitude Modulation (PAM), Generation and Demodulation of PAM, Pulse-Width Modulation, Generation and Demodulation of PWM, Pulse Position Modulation, Generation and Demodulation of PPM, PAM-TDM, Noise Performance of Pulse Analog Modulation Systems, Solved Problems, Summary, Short Questions with Answers, Review Questions, Answer Key, Unsolved Problems, Multiple Choice Questions, Answer Key.
   
  P. Paper