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1. Classified by communication service According to the different types of communication services, communication systems can be divided into telegraph communication systems, telephone communication systems, data communication systems, image communication systems, etc. Because the telephone commun...

(1) Source coding and decoding Two basic functions: one is to improve the effectiveness of information transmission, that is, through some kind of compression coding technology to try to reduce the number of symbols to reduce the symbol rate. The second is to complete the analog/digital (A/D) con...

Both signal and noise in communication can be regarded as random processes that change with time. Random process has the characteristics of random variable and time function, which can be described from two different but closely related perspectives: (1) Random process i...

The communication mode refers to the working mode or signal transmission mode between the two communication parties. 1. Simplex, half-duplex, and full-duplex communication For point-to-point communication, according to the direction and time of message transmission, the ...

In a digital communication system, what the receiver receives is the sum of the transmitted signal and the channel noise. The optimal reception of digital signals is based on the minimum error probability as the "best" criterion. Errors considered in this chapter are mai...

Figure 6-6 is a block diagram of a typical digital baseband signal transmission system. It is mainly composed of sending filter (channel signal generator), channel, receiving filter and sampling decision. In order to ensure the reliable and orderly work of the system, th...