Types of wireless communication systems According to the different characteristics of key parts of wireless communication systems, there are the following types:
1. Classified according to working frequency band or transmission method, there are medium wave communication, short wave communication, ultra short wave communication, microwave communication and satellite communication. The so-called operating frequency mainly refers to the radio frequency (RF) frequency of transmission and reception. Radio frequency is actually a broad term for "high frequency". It refers to a frequency suitable for radio transmission and propagation. One development direction of wireless communication is to open up higher frequency bands. ?
2. According to the communication method, there are (full) duplex, half duplex and simplex.
3. It is divided according to different modulation methods, including amplitude modulation, frequency modulation, phase modulation and mixed modulation.
4. According to the type of message transmitted, there are analog communication and digital communication, and it can also be divided into voice communication, image communication, data communication and multimedia communication. ?
For different types of communication systems, the system composition and the complexity of the equipment are very different. But the basic circuits and the principles that make up the device are the same and follow the same rules. This book will focus on analog communication to study these basic circuits and understand their laws. These circuits and laws can be widely applied to other types of communication systems.
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