Shulou(Shulou.com)06/03 Report--

Today, I would like to talk to you about what communication is, many people may not know much about it. In order to make you understand better, the editor summed up the following contents for you. I hope you can get something from this article.

Communication refers to the exchange and transmission of information between people and people or between people and nature through a certain behavior or medium. in a broad sense, it means that two or more parties who need information use any method and any medium without going against their own will. accurately and safely transmit information from one party to another.

Communication has different interpretations in different environments. After the emergence of radio transmission communication, Communication is simply interpreted as the transmission of information, which refers to the transmission and exchange of information from one place to another, and its purpose is to transmit messages.

However, in the process of human practice, with the development of social productive forces, the continuous improvement of the requirements for the transmission of information makes the continuous progress of human civilization.

Among all kinds of communication methods, the communication method that uses "electricity" to transmit messages is called Telecommunication. This kind of communication has the characteristics of rapidness, accuracy and reliability, and is almost not limited by time, place, space and distance, so it has been developed rapidly and widely used.

Nowadays, due to the rapidity of radio waves, the physical communication (postal communication), which combines cultural exchange with the continuous accumulation and progress of the real economy from the ancient human material exchange process, is understood as an obstacle to economic development.

In ancient times, human beings transmitted information through post stations, flying pigeons, beacon alarms, symbols, body language, eyes, touch and so on.

With the rapid development of modern science, a variety of communication methods have emerged, such as radio, fixed telephone, mobile phone, Internet and even video phone. Communication technology shortens the distance between people, improves economic efficiency, and profoundly changes human life style and social appearance.

classification

1. Classification by transmission medium

Wired communication: refers to the communication in the form of wires, cables, optical cables, waveguides, nanomaterials, etc., which is characterized by the fact that the media can be seen and touched (open wire communication, cable communication, optical cable communication, optical fiber and optical cable communication).

Wireless communication: refers to a form of communication in which the transmission medium is invisible and untouchable (such as electromagnetic waves).

Microwave communication, shortwave communication, mobile communication, satellite communication, scattering communication.

2. Classification according to the signals transmitted in the channel

Analog signal: where a certain parameter of the signal (such as the amplitude, frequency and phase of the continuous wave, the amplitude, width and position of the pulse wave, etc.) can take an infinite number of values, and directly corresponding to the message, the analog signal is sometimes called a continuous signal. This continuity means that a certain parameter of the signal can be changed continuously.

Digital signal: where a parameter of a signal can only take a limited number of values, and often does not directly correspond to the message, also known as discrete signal [1].

3. Classify by working frequency band

long-wave communication.

Medium wave communication.

Shortwave communication.

Microwave communication.

4. Classification according to modulation

Baseband transmission: means that the signal is sent directly to the channel for transmission without modulation

The mode of communication.

Band transmission: means that the signal is modulated and then sent to the channel for transmission, the receiving end

The mode of communication with corresponding demodulation measures.

5. Classified according to the division of labor between the two sides of the communication and the direction of data transmission.

According to the direction of message transmission, point-to-point communication can be divided into three types: simplex communication, half-duplex communication and full-duplex communication.

The so-called simplex communication refers to a communication mode in which messages can only be transmitted in one direction. There are many examples of simplex communication, such as broadcasting, remote control, wireless paging and so on. Here, the signal (message) is only transmitted from the broadcast transmitter, the remote control and the wireless paging center to the radio, the remote control object and the BP machine, respectively.

The so-called half-duplex communication means that both sides of the communication can send and receive messages, but can not receive and send messages at the same time. Walkie-talkies, transceivers and so on are all in this way of communication.

The so-called full-duplex communication refers to the way in which both sides of the communication can transmit messages in both directions at the same time. In this way, both parties can send and receive messages at the same time. Obviously, the channel for full-duplex communication must be a two-way channel. There are many examples of full-duplex communication in life, such as ordinary telephone, mobile phone and so on.

Composition

All the technical equipment and transmission media needed to realize information transmission are collectively referred to as communication systems.

Source: the place of origin of a message whose function is to convert various messages into original electrical signals, which are called message signals or baseband signals. Telephones, television cameras, telex machines, computers and other digital terminal equipment are the sources of information.

Sending equipment: match the source and the channel, that is, the message signal generated by the source is transformed into an occasion suitable for moving in the channel. Modulation is the most common way of transformation. Modulation is the most common transformation method in situations where spectrum shift is needed. For digital communication systems, transmitting equipment is often divided into source coding and channel coding.

Channel: the physical medium that transmits signals.

Noise source: it is inherent in all kinds of equipment and channel in the communication system. For the convenience of analysis, the noise source is abstractly added to the channel as a concentrated expression of noise everywhere.

Receiving equipment: complete the inverse transformation of the sending equipment, that is, demodulation, decoding, decoding and so on. Its task is to correctly recover the corresponding original baseband signal from the received signal with interference.

Destination: the destination of transmitted information, whose function is to convert the recovered original signal into corresponding information.

After reading the above, do you have any further understanding of what communication is? If you want to know more knowledge or related content, please follow the industry information channel, thank you for your support.

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