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Noise in the Channel

Optical fibers are wired channels that transmit optical signals. We refer to the unnecessary electrical signals in the channel as noise. The noise in the communication system is superimposed on the signal, and there is also noise in the communication system when there is no transmission signal, a... Read More

The Signal Channel

The channel connects the communication device of the sending end and the receiving end, and its function is to transmit the signal from the sending end to the receiving end. According to the different transmission media, channels can be divided into two categories: wireless channels and wired cha... Read More

Communication System Model

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... Read More

Communication system Model

(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... Read More

Random Processes in Communication systems

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 is the set of infinite samp... Read More

Communication Mode

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 communication mode can be ... Read More