Practical Communication Theory

by Dave Adamy

Overview

Practical Communication Theory, 2nd Edition enables the reader to quickly and easily generate the answers to real-world problems encountered in specifying, testing, and fielding any type of systems that involve radio propagation. It deals with free space radio propagation and propagation near the ground and over the ridge lines.

Now in its second edition, Practical Communication has been updated to include new material on radio propagation near the earth in communication bands, which also explains how to use the slide rule scales for each of the appropriate propagation modes. The section on dynamic range has been expanded and there is additional material on knife-edge diffraction. The appendices have also been updated to include extra propagation formulae and graphs.

Please note, this book contains mention of a slide rule, which was previously provided alongside the product upon purchase. However, due to a change in distribution processes, the publisher is unfortunately no longer able to provide slide rules to customers. We apologise for any inconvenience caused.

Product Details

ISBN-13:	9781613531860
Publisher:	The Institution of Engineering and Technology
Publication date:	08/18/2014
Series:	Electromagnetic Waves
Edition description:	2nd ed.
Pages:	176
Product dimensions:	6.30(w) x 9.40(h) x 0.70(d)

About the Author

Dave Adamy is an internationally recognised expert in electronic warfare. He has 50 years of experience as a systems engineer and program technical director, developing EW systems from DC to Light, deployed on platforms from submarines to space, with specifications from QRC to high reliability. For the last 30 years, he has run his own company, performing studies for the US Government and defense contractors. He has also presented a number of courses in the US, Europe and Australia on Electronic Warfare and related subjects. He has published over 330 professional articles on Electronic Warfare, receiver system design and closely related subjects, including the popular EW101 column in the Journal of Electronic Defense. He has 15 books in print and is a past National President of the Association of Old Crows.

Table of Contents

About the Author ix

Preface xi

Preface to the First Edition xii

Acknowledgements xiv

1 Introduction 1

1.1 The Communication Link 1

1.2 A Few Important Definitions 3

1.3 Assumptions 4

1.4 Scope of the Book 4

Appendixes 4

2 About dB 7

1.1 Conversion to dB Form 8

2.1 Absolute Values in dB Form 9

2.2 dB Forms of Equations 9

2.3 Quick Conversions to dB Values 10

2.4 dB Bookkeeping Diagrams 12

3 Signal-to-Noise Ratio 15

3.1 Noise 15

3.2 Signal-to-Noise Ratio 16

3.3 Other Related Ratios 18

3.3.1 RF SNR 18

3.3.2 Signal-to-Quantization Ratio 18

3.4 Background Noise 19

4 The Communication Link 23

4.1 Information Signals 23

4.1.1 Audio Signals 23

4.1.2 Digital Data 24

4.1.3 Video Signals 25

4.2 Transmitters 27

4.2.1 Modulator 28

4.2.2 Power Amplifier 35

4.3 Receivers 36

4.3.1 Fixed Tuned Receiver 37

4.3.2 Channelized Receiver 37

4.3.3 Superheterodyne Receiver 38

4.3.4 Crystal Video Receiver 40

4.3.5 IFM Receiver 41

4.3.6 Compressive Receiver 41

4.3.7 Digital Receiver 42

4.3.8 Receiving Systems 43

4.4 Antennas 44

4.4.1 Antenna Gain Pattern 44

4.4.2 Polarization 47

4.4.3 Types of Antennas 49

4.5 Antenna Slide Rule 55

4.5.1 Antenna Scales 56

4.5.2 Finding Gain and Beamwidth 56

4.6 The Ether Waves 60

5 The Link Equation 61

5.1 Link Losses 63

5.1.1 Free Space 63

5.1.2 Two-Ray Loss 67

5.1.3 Fresnel Zone 70

5.1.4 Knife-Edge Diffraction 73

5.1.5 Atmospheric Loss 75

5.2 Signal Strength at Various Points in the Communication Link 76

5.2.1 Effective Radiated Power 77

5.2.2 Signal Arriving at Antenna 79

5.2.3 Received Power 80

5.3 Link Design Parameters 81

5.3.1 Required Margin 81

5.3.2 Required Sensitivity 82

5.3.3 Effective Range 83

5.3.4 Required Transmitter Power or Antenna Gain 86

5.4 Interfering Signals 88

5.5 Dynamic Range 91

6 Receiver Sensitivity and Dynamic Range 93

6.1 Sensitivity 93

6.1.1 Thermal Noise Level 94

6.1.2 Noise Figure 95

6.1.3 Required SNR 98

6.2 Digitized Analog Signals 99

6.2.1 Sampling Rate 100

6.2.2 Quantizing Levels 100

6.2.3 RF SNR 101

6.3 Dynamic Range 102

6.3.1 Analog versus Digital Dynamic Range 103

6.3.2 Analog Receiver Dynamic Range 104

6.3.3 Determining Dynamic Range 106

6.4 Digital Dynamic Range 107

7 Challenging Conditions 109

7.1 Rain and Fog Attenuation 109

7.2 Non-Line of Sight Transmission 111

7.2.1 Knife Edge Diffraction 111

7.2.2 Diffraction Loss over a Smooth Sphere 112

7.3 Doppler Effect 113

7.4 Antenna Misalignment 114

Appendix A Derivation of Equations and Charts 117

Appendix B Signal Strength in the Ether Waves 123

Appendix C Quick Formulas for Antennas 127

Appendix D Quick Formulas for Receiver Sensitivity and Dynamic Range 133

Appendix K Quick Formulas for Propagation 137

Appendix F Quick Formulas for Doppler Shift 149

Appendix G Antenna and Propagation Slide Rule 151

Index 157

Editorial Reviews

'This book very nicely covers the design and analysis of real-life radio point-to-point communications in an easy to understand, but very practical (as promised by the title) way'

Joel R. Hallas

"This book very nicely covers the design and analysis of real-life radio point-to-point communications in an easy to understand, but very practical (as promised by the title) way, that will make sense to most QST readers."

From the Publisher