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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

Optimal reception of digital signals

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 mainly caused by ... Read More

The composition of digital baseband signal transmission system

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, there should also be a synch... Read More

Frequency division multiplexing

When the transmission capacity of a physical channel is higher than the demand for one signal, the channel can be shared by multiple signals, for example, the trunk line of a telephone system often has thousands of signals transmitted in a single fiber. Multiplexing is a technology to solve how t... Read More

Common code type of baseband transmission

(1) AMI code AMI(Alternative Mark Inversion) code is the full name of alternate mark inversion code, its encoding rule is to alternately transform the message code “1″ (mark) to “+1″ and “-1″, while the “0″ (empty sign) remains unchanged. For exampl... Read More