What Are the Different Types of Communication Systems?
Communication system is a general term for technical systems used to complete information transmission processes. Modern communication systems are mainly implemented by means of electromagnetic wave propagation in free space or transmission mechanisms in guiding media. The former is called a wireless communication system and the latter is called a wired communication system.
Communication Systems
- Definition: A system that uses electrical signals (or optical signals) to transmit information, also known as telecommunications systems. A system is usually an organic whole that consists of several units with specific functions, interactions, and interdependencies to accomplish a unified goal. The simplest communication system is for two users to send and receive information to each other. In a general communication system, a user can communicate with other users in the system through a switching device.
- It is generally composed of source (originating equipment), sink (receiving equipment), and channel (transmission medium). It is called the three elements of communication.
- To make the most of
- For long distances
- Long-distance and large-capacity radio communication systems
- In a microwave communication system, if a communication satellite located in the geostationary orbit is used as a repeater repeater
- The characteristic of telephone communication is that the two parties of the call require real-time conversation, so a path must be temporarily connected between the two parties in a relatively short period of time. Therefore, the telephone communication system should have both transmission and exchange functions. This system usually consists of subscriber lines, switching centers, inter-office trunks, and trunk lines.
- A communication system established to enable telegram users to communicate with each other. It mainly uses the telephone path to transmit telegraph signals.
- How to measure the quality of a communication system? We measure it primarily by effectiveness and reliability. In other words, the more efficient and reliable a communication system is, the better it is. But in fact effectiveness and reliability are a pair of contradictory indicators, and the two need a certain compromise. Validity refers to the rate of information transmission. The faster the rate of information transmission, the better the effectiveness. However, the faster the information transmission, the higher the probability of errors, and the transmission quality of the information cannot be guaranteed, that is, the reliability is reduced. It's like a car speeding on a highway. It's almost fast, but it has great safety risks. So you can't just set aside speed and simply pursue high speed; otherwise, you really want to be fast and not reach it.
- So what specific indicators are used to illustrate the effectiveness and reliability of the system?
- For analog communication systems, effectiveness is measured by the system's bandwidth, and reliability is measured by the signal-to-noise ratio. If the bandwidth occupied by one phone is constant, the larger the total bandwidth of the system, it means that more phones can be accommodated. When the bandwidth of the system is constant, to increase the capacity of the system, it can be achieved by reducing the bandwidth occupied by a single telephone. Therefore, the narrower the bandwidth required for a single signal, the better the effectiveness. However, after reducing the occupied bandwidth of a single signal, because the band isolation between the two signals is narrowed, it will inevitably increase mutual interference, that is, increase noise, and reduce the ratio of signal power to noise power, thereby reducing the reliability of the system. Sex.
- For digital communication systems, effectiveness is represented by the information transmission rate, and reliability is represented by the bit error rate or the mistrust rate. The bit error rate refers to the ratio of the number of error symbols received by the receiving end to the total number of transmission symbols, that is, the probability of error symbols occurring during transmission. The false positive rate refers to the ratio of the number of received error bits to the total number of transmitted bits, that is, the probability of the amount of error information in the transmission.
- When digital signals are transmitted in a channel, in order to ensure the reliability of transmission, error correction coding is often added, and error correction coding occupies the transmission rate. When the total number of symbols or bits that a channel can transmit per second is constant, if error correction coding is not required, it is obvious that the amount of information transmitted per second will be more, and the efficiency is improved. Can not guarantee. These codes added to improve reliability are also called transmission overhead, because the purpose of transmitting these symbols or bits is to pick up errors and correct errors, and they do not carry information.
- In communication systems, frequency is a characteristic that is inherent to any signal. Even digital signals are no exception. Transmission of them takes up certain frequency resources. The bandwidth is directly proportional to the transmission rate of the digital signal. Ideally, the transmission rate divided by 2 is the bandwidth occupied by digital signals transmitted at this rate. Therefore, the band occupied by higher rates will be wider, so high-speed communication is often called "broadband communication."
- Title: Communication System
- Publisher: Electronic Industry Press
- Publication time: 2010-1-1
- ISBN: 9787121102325
- Folio: 16
- Price: 79.00 yuan
Introduction to communication system content
- This book conducts an in-depth analysis of the basic theory and key links of communication systems, in an attempt to let students understand the essence of communication in the discussion. The book first gives an overview of communication systems and key technologies that need to be studied, and then discusses in detail chapters on random processes, continuous wave modulation, pulse modulation, baseband pulse transmission, signal space analysis, bandpass digital transmission, spread spectrum modulation, multi-user Wireless communication, information theory, and error control coding, etc., each chapter is accompanied by a large number of exercises for students to practice. This book emphasizes the statistical basis of communication theory, and gives eight computer experiments simulated with MATIAB. These experiments almost cover the main content of each chapter, forming a unique communication theory "software laboratory".
- This book can be used as a textbook for senior undergraduates of communication, information, electronics, computer and other majors in colleges and universities, and can also be used as a reference for related technical, scientific and management personnel.
Communication system author profile
- Simon Haykin, IEEE Fellow, graduated from the Department of Electrical Engineering at the University of Birmingham, UK. Professor, Department of Electronics and Computer Engineering, McMaster University, Canada, Director of Communications Research Lab. Research interests include nonlinear dynamics, neural networks, and adaptive filters and their applications.
Communication System Book Catalog
- BACKGROUND AND PREVIEW
- CHAPTER 1 Random Processes
- CHAPTER 2 Continuous-Wave Modulation
- CHAPTER 3 Pulse Modulation
- CHAPTER 4 Baseband Pulse Transmission
- CHAPTER 5 Signal-Space Analysis
- CHAPTER 6 Passband Digital Transmission
- CHAPTER 7 Spread-Spectrum Modulation
- CHAPTER 8 Multiuser Radio Communications
- CHAPTER 9 Fundamental Limits in Information Theory
- CHAPTER 10 Error-Control Coding
- APPENDIX 1 Probability Theory
- APPENDIX 2 Representation of Signals and Systems
- APPENDIX 3 Bessel Functions
- APPENDIX 4 Confluent Hypergeometric Functions
- APPENDIX 5 Cryptography
- APPENDIX 6 Tables
- GLOSSARY
- BIBLIOGRAPHY
- INDEX
- Communication system related terminology: [1]
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|