Communication Systems/Print Version Wikibooks.org March 24, 2011. Contents 0.1 INTRODUCTION ....................................... 1 0.2 TABLEOF CONTENTS .................................... 1 0.3 INTRODUCTION ....................................... 1 0.4 WHOIS THIS BOOK FOR? ................................. 2 0.5 WHAT THIS BOOKWILL COVER .............................. 2 0.6 WHERE TO GO FROM HERE ................................ 2 0.7 DIVISIONOF MATERIAL .................................. 3 0.8 ABOUT THIS BOOK ..................................... 4 0.9 CHRONOLOGY ........................................ 4 0.10 CLAUDE SHANNON ..................................... 6 0.11 HARRY NYQUIST ....................................... 6 0.12 WIDEBANDVS NARROWBAND ............................... 6 0.13 FREQUENCY SPECTRUM .................................. 6 0.14 TIME DIVISION MULTIPLEXING .............................. 7 0.15 ZERO SUBSTITUTIONS ................................... 13 0.16 BENEFITS OF TDM..................................... 18 0.17 SYNCHRONOUS TDM ................................... 18 0.18 STATISTICAL TDM ..................................... 19 0.19 PACKETS ........................................... 22 0.20 DUTY CYCLES ........................................ 22 0.21 INTRODUCTION ....................................... 22 0.22 WHAT IS FDM? ....................................... 24 0.23 BENEFITS OF FDM ..................................... 26 0.24 EXAMPLESOF FDM..................................... 26 0.25 ORTHOGONAL FDM .................................... 26 0.26 VOLTAGE CONTROLLED OSCILLATORS (VCO)...................... 26 0.27 PHASE-LOCKED LOOPS ................................... 27 0.28 PURPOSEOF VCO AND PLL................................ 27 0.29 VARACTORS ......................................... 27 0.30 FURTHER READING ..................................... 27 0.31 WHAT IS AN ENVELOPE FILTER?.............................. 27 0.32 CIRCUIT DIAGRAM ..................................... 28 0.33 POSITIVE VOLTAGES .................................... 28 0.34 PURPOSEOF ENVELOPE FILTERS ............................. 28 0.35 DEFINITION ......................................... 29 0.36 TYPES OF MODULATION .................................. 29 0.37 WHY USE MODULATION? ................................. 30 0.38 EXAMPLES .......................................... 30 0.39 NON-SINUSOIDAL MODULATION ............................. 30 0.40 FURTHER READING ..................................... 31 III Contents 0.41 WHAT ARE THEY?...................................... 31 0.42 WHAT ARE THE PROS AND CONS?............................. 31 0.43 SAMPLINGAND RECONSTRUCTION ............................ 32 0.44 FURTHER READING ..................................... 32 0.45 TWISTED PAIR WIRE .................................... 32 0.46 COAXIAL CABLE ....................................... 33 0.47 FIBER OPTICS ........................................ 33 0.48 WIRELESS TRANSMISSION ................................. 33 0.49 RECEIVER DESIGN ..................................... 34 0.50 THE SIMPLE RECEIVER ................................... 35 0.51 THE OPTIMAL RECEIVER .................................. 35 0.52 CONCLUSION ........................................ 36 0.53 FURTHER READING ..................................... 36 0.54 ANALOG MODULATION OVERVIEW ............................ 36 0.55 TYPES OF ANALOG MODULATION ............................. 36 0.56 THE BREAKDOWN ...................................... 37 0.57 HOW WE WILL COVER THE MATERIAL .......................... 37 0.58 AMPLITUDE MODULATION ................................ 37 0.59 AM DEMODULATION .................................... 55 0.60 AM-DSBSC......................................... 58 0.61 AM-DSB-C ......................................... 61 0.62 AM-SSB........................................... 62 0.63 AM-VSB........................................... 69 0.64 FREQUENCY MODULATION ................................ 70 0.65 FM TRANSMISSION POWER ................................ 76 0.66 FM TRANSMITTERS ..................................... 77 0.67 FM RECEIVERS ....................................... 77 0.68 PHASE MODULATION .................................... 77 0.69 WRAPPED/UNWRAPPED PHASE .............................. 84 0.70 PM TRANSMITTER ..................................... 85 0.71 PM RECEIVER ........................................ 85 0.72 CONCEPT ........................................... 85 0.73 INSTANTANEOUS PHASE .................................. 85 0.74 INSTANTANEOUS FREQUENCY ............................... 86 0.75 DETERMINING FM OR PM................................. 86 0.76 BANDWIDTH ......................................... 87 0.77 THE BESSEL FUNCTION .................................. 87 0.78 CARSON’S RULE ....................................... 88 0.79 DEMODULATION:FIRST STEP ............................... 88 0.80 FILTERED NOISE ...................................... 88 0.81 NOISE ANALYSIS ....................................... 89 0.82 ELECTROMAGNETIC SPECTRUM .............................. 89 0.83 RADIO WAVES ........................................ 90 0.84 FADINGAND INTERFERENCE ............................... 95 0.85 REFLECTION ......................................... 100 0.86 DIFFRACTION ........................................ 100 0.87 PATH LOSS .......................................... 100 0.88 RAYLEIGH FADING ..................................... 100 IV Contents 0.89 RICIAN FADING ....................................... 100 0.90 DOPPLER SHIFT ....................................... 100 0.91 TYPES OF NOISE ....................................... 100 0.92 NOISE TEMPERATURE ................................... 105 0.93 NOISE FIGURE ........................................ 105 0.94 RECEIVER SENSITIVITY ................................... 109 0.95 CASCADED SYSTEMS .................................... 109 0.96 TRANSMISSION LINE EQUATION ............................. 109 0.97 THE FREQUENCY DOMAIN ................................. 118 0.98 CHARACTERISTIC IMPEDANCE ............................... 122 0.99 ISOTROPIC ANTENNAS ................................... 123 0.100 DIRECTIONAL ANTENNAS ................................. 124 0.101 LINK-BUDGET ANALYSIS .................................. 125 0.102 TECHNICAL CATEGORISATIONS .............................. 126 0.103 MULTIPATHING ....................................... 126 0.104 APPLICATION SYSTEMS ................................... 126 0.105 DEFINITION ......................................... 126 0.106 SQUARE WAVE ........................................ 127 0.107 OTHERPULSES ....................................... 127 0.108 SINC ............................................. 127 0.109 COMPARISON ........................................ 127 0.110 SLEW-RATE-LIMITEDPULSES ............................... 128 0.111 RAISED-COSINE ROLLOFF ................................. 128 0.112 BINARY SYMMETRIC PULSES ................................ 128 0.113 ASYMMETRIC PULSES .................................... 129 0.114 ASYMMETRIC CORRELATION RECEIVER . 129 0.115 REFERENCES ......................................... 129 0.116 WHAT IS "KEYING?" .................................... 129 0.117 AMPLITUDE SHIFT KEYING ................................ 130 0.118 FREQUENCY SHIFT KEYING ................................ 130 0.119 PHASE SHIFT KEYING .................................... 131 0.120 BINARY TRANSMITTERS .................................. 132 0.121 BINARY RECEIVERS ..................................... 132 0.122 PRONUNCIATION ...................................... 132 0.123 EXAMPLE:4-ASK...................................... 133 0.124 BITS PER SYMBOL ...................................... 133 0.125QPSK............................................. 133 0.126CPFSK(MSK) ....................................... 133 0.127DPSK............................................. 133 0.128 FOR FURTHER READING .................................. 133 0.129 DEFINITION ......................................... 134 0.130 CONSTELLATION PLOTS .................................. 134 0.131 BENEFITS OF QAM ..................................... 135 0.132 FOR FURTHER READING .................................. 135 0.133 DEFINITION ......................................... 135 0.134 CONSTELLATION PLOTS .................................. 136 0.135 BENEFITS OF QAM ..................................... 136 0.136 FOR FURTHER READING .................................. 136 V Contents 0.137 LINE CODES ......................................... 137 0.138 NON-RETURN TO ZERO CODES (NRZ).......................... 140 0.139 MANCHESTER ........................................ 142 0.140 DIFFERENTIAL CODES ................................... 142 0.141 COMPARISON ........................................ 143 0.142 FURTHER READING ..................................... 143 0.143 PURPOSE ........................................... 145 0.144 CONNECTIONMETHODS .................................. 145 0.145 DATA FORMAT ........................................ 146 0.146 FTP RETURN CODES .................................... 147 0.147 ANONYMOUS FTP ..................................... 147 0.148 COMMANDS ......................................... 148 0.149 FURTHER READING ..................................... 149 1 AUTHORS 151 LISTOF FIGURES 153 1.1 LICENSE ........................................... 155 VI Introduction Current Status: 0.1 Introduction This book will eventually cover