本教材可供高等院校信息科學、通信工程、電子技術、計算機應用等專業的本科生和研究生學習專業英語之用，亦可供廣大英語學習愛好者參考。本書選材兼顧經典題材和新興技術，在編寫中力求改革創新，強調大量實踐，注重培養學生以較高準確性和足夠的速度閱讀專業資料和文獻的能力，兼顧一定的專業英語表達能力。全書共18單元，各單元包括課文、詞彙、難點注釋、課外閱讀資料、習題。課文內容涉及電子技術、通信工程、信息處理、計算機應用等領域的基礎知識和新技術進展，每一單元包括2～3篇科技文章或技術資料。對部分科技術語和重要概念提供簡要的英文輔助資料，以便於理解課文，並在學習科技英語的同時擴大專業知識面。書後附有關於科技英語閱讀、寫作、克服中式英語等問題的指南和討論。

\"本書供高等院校信息科學、通信工程、電子技術、計算機應用等專業的本科生和研究生學習專業英語之用。選材兼顧經典題材和新興技術，在編寫中擯棄過分依賴語法、死記硬背的陳舊教學方法，注重培養學生以較高準確性和足夠的速度閱讀專業資料和文獻的能力，兼顧一定的專業英語表達能力，從閱讀、翻譯、寫作等角度提高學生對專業英語的應用能力。 　　全書共17單元，各單元包括課文、詞彙、難點注釋、課外閱讀資料、習題。書後附有關於科技英語閱讀、寫作、克服中式英語等問題的指南和討論。 \"

　　
　　
　　
　　
　　
　　
　　
　　
Unit 1 Electronics: Analog and Digital 1
Text 1
Part I: Ideal Operational Amplifiers and Practical Limitations 1
Part II: Data Registers and Counters 3
Part III: Nature of Phase Lock 6
New Words 8
Notes on the Text 9
Technical Tips 12
Supplementary Readings: Bridging the Gap between the
Analog and Digital Worlds 13
Exercises 17
Unit 2 Integrated Circuits 21
Text 21
Part I: The Integrated Circuit 21
Part II: Application Specific Integrated Circuit 24
New Words 27
Notes on the Text 28
Technical Tips 31
Supplementary Readings 31
Exercises 34
Unit 3 EM Fields, Antenna and Microwaves 37
Text 37
Part I: Electromagnetic Field 37
Part Ⅱ: Microstrip Antenna 38
Part Ⅲ: Microwaves 40
New Words 43
Notes on the Text 44
Technical Tips 46
Supplementary Readings: What Are Microwaves? 46
Exercises 50
Unit 4 Communication and Information Theory 53
Text 53
Part I: Telecommunication 53
Part Ⅱ: Data Transmission 55
Part Ⅲ: Information Theory 56
New Words 59
Notes on the Text 60
Technical Tips 63
Supplementary Readings 63
Exercises 66
Unit 5 Multiple Access Techniques 70
Text 70
Part I: Multiple Access Techniques: FDMA, TDMA and CDMA 70
Part Ⅱ: Orthogonal Frequency Division Multiplexing 76
New Words 79
Notes on the Text 80
Technical Tips 82
Supplementary Readings: Wavelength-Division Multiplexing 82
Exercises 85
Unit 6 Mobile Communications 88
Text 88
Part I: Mobile Communications 88
Part Ⅱ: Fourth Generation Wireless Networks 91
New Words 94
Notes on the Text 95
Technical Tips 97
Supplementary Readings: The Road to 5G 98
Exercises 102
Unit 7 Optical Communications 104
Text 104
Part I: Electromagnetic Spectrum 104
Part Ⅱ: Optical Fiber 107
New Words 111
Notes on the Text 112
Technical Tips 115
Supplementary Readings: Optical Systems 116
Exercises 119
Unit 8 Digital Signals and Signal Processing 122
Text 122
Part I: Digital Signal Processing 122
Part Ⅱ: General Concepts of Digital Signal Processing 125
New Words 130
Notes on the Text 132
Technical Tips 134
Supplementary Readings: Designing Digital Filters 135
Exercises 141
Unit 9 Digital Audio Compression 145
Text 145
Part I: MPEG Audio Layer 3 145
Part Ⅱ: Digital Audio Compression Standard AC3 147
New Words 151
Notes on the Text 152
Technical Tips 154
Supplementary Readings: Audio Compression Algorithm Overview 155
Exercises 159
Unit 10 Digital Image Processing 162
Text 162
Part I: Two-Dimensional Digital Images 162
Part Ⅱ: Digital Images ? Definition and Applications 164
Part Ⅲ: Introduction to Image Processing 167
New Words 172
Notes on the Text 174
Technical Tips 180
Supplementary Readings 180
Exercises 186
Unit 11 Biometrics Technology 188
Text 188
Part I: Fingerprint Identification 188
Part Ⅱ: Introduction to Speaker Identification 190
New Words 195
Notes on the Text 196
Technical Tips 199
Supplementary Readings: Biometrics Overview 200
Exercises 204
Unit 12 Information Security 207
Text 207
Part I: Information Security — Introduction and a Brief History 207
Part Ⅱ: Basic Principles of Information Security 208
Part Ⅲ: Intrusion Detection System 210
New Words 212
Notes on the Text 214
Technical Tips 217
Supplementary Readings: Hidden Communication 218
Exercises 223
Unit 13 Telemedicine and Biomedical Signal Processing 226
Text 226
Part I: Telemedicine 226
Part Ⅱ: Computerized Tomographic Imaging 228
New Words 230
Notes on the Text 231
Technical Tips 234
Supplementary Readings: Biomedical Signal Processing 234
Exercises 237
Unit 14 Computers and Networks 240
Text 240
Part I: Evolution of Computers 240
Part Ⅱ: Local Area Networks 244
New Words 249
Notes on the Text 250
Technical Tips 253
Supplementary Readings 254
Exercises 258
Unit 15 Artificial Intelligence 262
Text 262
Part I: What Is Artificial Intelligence 262
Part Ⅱ: Approaches of AI 264
New Words 268
Notes on the Text 269
Technical Tips 271
Supplementary Readings: AlphaGo 272
Exercises 275
Unit 16 Big Data and Cloud Computing 278
Text 278
Part I: Big Data 278
Part Ⅱ: Cloud Computing 282
New Words 286
Notes on the Text 287
Technical Tips 289
Supplementary Readings: Smart City 290
Exercises 294
Unit 17 Internet of Things (IoT) 296
Text 296
Part I: Internet of Things: Concept and Key Technologies 296
Part Ⅱ: IoT Applications 299
New Words 303
Notes on the Text 304
Technical Tips 306
Supplementary Readings: Wireless Sensor Network 307
Exercises 310
Appendices 312
I. How Should We Read English 312
Ⅱ. Writing Technical English 314
Ⅲ. Avoid Pidgin English 329
Ⅳ. Title of Scientific Papers 337
Ⅴ. How to Write Abstract 339
Bibliography 343

Multiple Access Techniques 　　Today the rapidly increasing communications systems are operating in an increasingly crowded frequency spectrum. The only solution appears to be sharing the precious frequency resources among different users, and there comes the need for developing various multiple access techniques. Text Part I: Multiple Access Techniques: FDMA, TDMA and CDMA 　　Multiple access schemes are used to allow many simultaneous users to use the same fixed bandwidth radio spectrum. In any radio system, the allocated bandwidth is always limited. For mobile phone systems the total bandwidth is typically 50MHz, which is split in half to provide the forward and reverse links of the system. Sharing of the spectrum is required in order to increase the user capacity of any wireless network. FDMA, TDMA and CDMA are the three major methods of sharing the available bandwidth to multiple users in wireless system. There are many extensions, and hybrid techniques for these methods, such as OFDM, and hybrid TDMA and FDMA systems. However, an understanding of the three major methods is required for understanding of any extensions to these methods. 　　Frequency division multiple access 　　In Frequency Division Multiple Access (FDMA), the available bandwidth is subdivided into a number of narrower bands. Each user is allocated a unique frequency band in which to transmit and receive. During a call, no other user can use the same frequency band. Each user is allocated a forward link channel (from the base station to the mobile phone) and a reverse channel (back to the base station), each being a single way link. The transmitted signal on each of the channels is continuous allowing analog transmissions. The bandwidths of FDMA channels are generally low (30 kHz) as each channel only supports one user. FDMA is used as the primary breakup of large allocated frequency bands and is used as part of most multi-channel systems. Figures 5.1 and 5.2 show the allocation of the available bandwidth into several channels. Figure 5.1 FDMA showing that the each narrow band channel is allocated to a single user Figure 5.2 FDMA spectrum, where the available bandwidth is subdivided into narrower band channels 　　Time division multiple access 　　Time Division Multiple Access (TDMA) divides the available spectrum into multiple time slots, by giving each user a time slot in which they can transmit or receive. Figure 5.3 shows how the time slots are provided to users in a round robin fashion, with each user being allotted one time slot per frame.1 Figure 5.3 TDMA scheme where each user is allocated a small time slot 　　TDMA systems transmit data in a buffer and burst method, thus the transmission of each channel is non-continuous. The input data to be transmitted is buffered over the previous frame and burst transmitted at a higher rate during the time slot for the channel.2 TDMA cannot send analog signals directly due to the buffering required, thus is only used for transmitting digital data. TDMA can suffer from multipath effects as the transmission rate is generally very high. This leads the multipath signals causing inter-symbol interference. 　　TDMA is normally used in conjunction with FDMA to subdivide the total available bandwidth into several channels. This is done to reduce the number of users per channel allowing a lower data rate to be used. This helps reduce the effect of delay spread on the transmission. Figure 5.4 shows the use of TDMA with FDMA. Each channel based on FDMA, is further subdivided using TDMA, so that several users can transmit over one channel. This type of transmission technique is used by most digital second generation mobile phone systems. For GSM, the total allocated bandwidth of 25MHz is divided into 125 channels using FDMA, each having a bandwidth of 200 kHz. These channels are then subdivided further by using TDMA so that each 200 kHz channel allows 8～16 users. Figure 5.4 TDMA/FDMA hybrid in which the bandwidth is split into frequency channels and time slots 　　Code division multiple access 　　Code Division Multiple Access (CDMA) is a spread spectrum technique that uses neither frequency channels nor time slots. In CDMA, the narrow band message (typically digitized voice data) is multiplied by a large bandwidth signal which is a pseudo random noise code (PN code). All users in a CDMA system use the same frequency band and transmit simultaneously. The transmitted signal is recovered by correlating the received signal with the PN code used by the transmitter. Figure 5.5 shows the general use of the spectrum using CDMA.