Communication Electronic Circuits

Zhiqun Cheng, Guohua Liu

• Publisher: De Gruyter
• Year: 2020
• ISBN:
  9783110592931
• Edition: 1
• Topic: Technology & Engineering
• Subtopic: Engineering General
• Index: Technology & Engineering

The book presents fundamentals of communication electronic circuits, including structure, principle, analyzing methodology, design and design software. Radio frequency amplifier, sinusoidal oscillator, amplitude modulation and demodulation, angular modulation and demodulation are described in detail. The book serves for learning and teaching but can also help researchers and professionals as reference.

Chapter 1 Introduction to basic knowledge of communication electronic circuits

1.1 Introduction to communication system

Communication is a process of delivering information from transmitter to receiver. All the required technical equipments and transmission medium during the process compose a communication system altogether. There are various approaches to realize information communication. The history can be traced back to the ancient times when the primitive methods were used widely such as beacons, courier stations and signal fires. The study on electromagnetism in the seventeenth century laid the theoretical foundation for modern communication. Samuel Morse invented the first telegraph device in 1837, which practically marked the beginning of modern electrical communication. Being fast, accurate, reliable and massive in global coverage, modern communication systems are playing irreplaceable roles in all aspects of life.

1.1.1 Composition of communication system

Modern communication systems are mainly in the forms of voltage signals, current signals, electromagnetic (EM) waves or light signals. In this book, communication refers to electrical communication. The general model of communication system is shown in Fig. 1.1.

Fig. 1.1: General model of communication system.

1.1.1.1 Signal source

Signal source is the origin of information, which can be analog or digital. Analog source outputs continuous signals, such as telephone and television. Digital source outputs discrete signals, such as computer and other digital terminal equipments.

The output signal of signal source is called baseband signal or modulation signal. Baseband signal (or modulation signal) refers to the original signal with the frequency spectrum starting from zero to low freq...