CONTENTS
Page No.
Chapter 1 : MODULATION SYSTEMS
1
1.1
Introduction
1
1.2
Development in Communication System
1
1.3
Modulation
4
1.4
Need for Modulation
4
1.5
Principles of Amplitude Modulation
6
1.5.1 Derivation of AM Signal
6
1.5.2 AM Envelope
8
1.5.3 AM Frequency Spectrum and Bandwidth
8
1.5.4 Coefficient of Modulation & Percent Modulation
9
1.5.5 Condition for Over, Under and Critical Modulation
11
1.5.6 AM Power Distribution
12
1.5.7 AM Current Calculation
14
AM Modulating Circuits
15
1.6.1 Low Level AM Modulator
16
1.6.2 Medium Power AM Modulator
17
AM Transmitter
20
1.7.1 Low Level Transmitter
20
1.7.2 High Level Transmitter
21
1.8
AM Receiver
22
1.9
Receiver Parameters
23
1.6
1.7
1.10 Direct FM Modulators
25
1.10.1 Varactor Diode Modulator
26
1.10.2 Varactor Diode VCO FM Modulator
27
1.10.3 FM Reactance Modulators
28
1.10.4 Linear Integrater Circuit Direct FM Modulators
29
1.11 Superheterodyne Receiver
30
1.12 Frequency Division Multiple Access
34
1.13 Pulse Modulation
40
1.14 Types of Modulator
40
Solved problems
42
Exercises
46
Questions
47
Chapter 2 : TRANSMISSION MEDIUM
49
2.1
Introduction
49
2.1.1 Terminology
49
2.1.2 Types of Transmission Mediums
50
2.2
Losses in Transmission
55
2.3
Characteristics impedence of Transmission Line
58
2.3.1 Impedence Matching
61
Standing Waves
66
2.4.1 Displacement and pressure, air column
67
2.4.2 The speed of a Wave
68
2.4.3 Formation of Standing Waves
68
2.4.4 Mathematics of Standing Waves
71
2.5
White Caussian Noise
74
2.6
Transmission System
75
2.6.1 Radio Coummunication
75
Radio Wave Propagation
85
2.7.1 Ground Wave
85
2.7.2 Sky waves
86
2.7.3 Space Waves
89
Scatter Propogation
90
2.8.1 Line of Sight
90
Estimating Path Loss
91
Two Mark Questions
100
Questions
102
2.4
2.7
2.8
2.9
Chapter 3 : DIGITAL COMMUNICATION
103
3.1
Pulse Code Modulation
103
3.1.1 PCM Transmission and Receiver
105
Time Division Multiplexing
110
3.2.1 Block Diagram of TDMA
112
Digital Modulation Techniques
114
3.2
3.3
3.4
Binary PSK
116
3.5
Quarternary Phase shift keying
121
3.5.1 QPSK Transmitter
121
3.5.2 Bandwidth Considerations of QPSK
123
3.5.3 QPSK Receiver
124
Differential phase shift keying (DPSK)
126
3.6.1 DBPSK Transmitter
126
3.6.2 DBPSK Receiver
126
3.6.3 Clock Recovery
127
Frequency shift Keying
128
3.7.1 FSK Bit rate and Baud
129
3.7.2 FSK Transmitter
129
3.7.3 FSK Receiver
131
3.8
PLL FSK Demodulator
132
3.9
Continuous Phase Frequency shift Keying (CP/FSK)(MSK)
132
3.6
3.7
3.10 Probability of Error and Bit Error rate
133
3.10.1 PSK Error Performance
136
3.11 Digital T-Carrier System
3.11.1 Description of History
138
138
3.12 Quadrature amplitude modulation
142
3.12.1 8 - QAM Transmitter
142
3.12.2 8 - QAM Reciver
143
3.12.3 QAM Error performace
144
3.13 Intersymbol Interference
145
Solved Problems
147
Exercises
150
Questions
152
Chapter 4 : DATA COMMUNICATION
153
4.1
Data Communications Code
153
4.1.1 The Binary System
153
4.1.2 Baudot Code
154
4.1.3 EBCDIC
156
4.1.4 ASCII
156
4.2
4.3
4.4
4.5
4.1.4.1 ASCII Control Characters
157
4.1.4.2 ASCII Printable Characters
159
Error Control
159
4.2.1 Polling
160
4.2.2 Stop and Wait ARQ
161
4.2.3 Go-Back-N Error Recovery
164
4.2.4 Selective Repeat Error Recovery
166
4.2.4.1 Features required for Selective Repeat ARQ
166
4.2.4.2 Recovery of lost PDUs using Selective Repeat ARQ
166
4.2.5 Comparison of ARQ Methods
168
Hardware Serial Interface
168
4.3.1 Hardware Overview
170
4.3.2 Parallel Interface
174
4.3.3 Asynchronous versus Synchronous Transmission
177
The Telephone Network
177
4.4.1 Telephone Switching System
177
4.4.2 Telephone Signalling SystemTechnologies
177
4.4.3 Telephone Transmission Technologies
178
Modem
179
4.5.1 Introduction
179
4.5.2 Origin of Modems
180
4.5.3 Speed of Modem
181
4.5.3.1 Why Difference in Speed with Cable Modem
4.5.4 Classification of Modems
181
183
4.5.4.1 Classifying Modems according to Range
183
4.5.4.2 Classifying Modems according to line type
184
4.5.4.3 Classifying Modems according to Operation Mode
185
4.5.4.4 Classifying Modems according to Synchronization
187
4.5.4.5 Classifying Modems according to Modulation
188
4.5.5 Data Rate
192
4.5.6 Choosing Your Internet Access Device and
Physical Connection
4.6
193
4.5.7 Classification of Modem with Speed
193
Local Area Network (LAN)
198
4.7
FDDI
202
4.8
OSI Model
205
4.9
Connection- Oriented and Connectionless Network Servoces
214
Questions
215
Chapter 5 : SATELLITE AND OPTICAL FIBRE
COMMUNICATIONS
217
5.1
Introduction
217
5.2
Satellite Orbits
220
5.3
Geostationary Satellite
222
5.3.1 Types of Satellites
223
Antenna Look Angles
224
5.4.1
230
5.4
Limits of Visibility
5.5
Satellite System Link Equation
5.6
Fibre Optic Data Communication Link for the Remises
5.7
231
Enviroment.
235
5.6.1
Fiber Optic Cable
238
5.6.2
Perfermance and Size
240
5.6.3
Composition or Material
241
5.6.4
Mode of Propogation
242
Optical Source
246
5.7.1
LED
246
5.7.2
LASER
246
5.7.3
ILD (Injection Laser Diode)
246
5.8
Optical Detector
247
5.9
Modulator
249
5.10 Connectors
251
5.11 Splicing
253
5.12 Advantages of Optical Fiber Communication
254
5.13 Types of Loss
255
Question
256
Index
257