Communication is the transfer of what

Communication is the transmission of "information". Communication refers to the exchange and transmission of information between people or between people and nature through some kind of behavior or media. In a broad sense, it means that two or more parties who need information can use any method without violating their respective wishes. The medium used to accurately and securely transmit information from one party to another.

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

Communication refers to the exchange and transmission of information between people or between people and nature through some behavior or medium. In a broad sense, it refers to two or more parties who need information without violating the Using any method and any medium to accurately and securely transmit information from one party to another if each party wishes to do so

In fact, communication has different interpretations in different environments. After the occurrence of radio wave transmission communication, communication (Communication) is simply interpreted as the transmission of information, which refers to the transmission and exchange of information from one place to another, with the purpose of transmitting messages. However, communication is a process of human practice. With the development of social productivity, the requirements for transmitting messages continue to increase, which makes human civilization continue to progress. Among various communication methods, the communication method that uses "electricity" to transmit messages is called telecommunication. This kind of communication has the characteristics of rapid, accurate and reliable, and is almost independent of time, place, space and distance. restrictions, it has been rapidly developed and widely used; today, due to the speed of radio waves, physical communication (postal communication), which has been continuously accumulated and progressed in the process of material exchange by ancient humans, has been understood by humans as a restriction. obstacles to economic development.

In ancient times, humans transmitted information through inns, flying pigeons delivering messages, beacon fire alarms, symbols, body language, eyes, and touch.

With the rapid development of modern scientific level, various communication methods such as radio, landline phone, mobile phone, Internet and even video phone have appeared one after another. Communication technology has shortened the distance between people, improved economic efficiency, and profoundly changed human lifestyles and social outlook

Classification of modern communication methods:

1. Classification by transmission medium

• Wired communication: refers to communication in the form of transmission media such as wires, cables, optical cables, waveguides, nanomaterials, etc. It is characterized by the fact that the medium can be seen and touched Author (Open Wire Communication, Cable Communication, Optical Cable Communication, Fiber Optic Cable Communication).

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

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

2. Classification according to the signal transmitted in the channel

• Analog signal: Any certain parameter of the signal (such as the amplitude, frequency, phase of the continuous wave, the amplitude, width, position of the pulse wave, etc.) can An analog signal that takes an infinite number of values ​​and directly corresponds to a message is sometimes called a continuous signal. This continuity means that a certain parameter of the signal can change continuously.

• Digital signal: Any signal parameter that can only take on a limited number of values ​​and often does not directly correspond to the message is also called a discrete signal.

3. Classification by working frequency band

• Long wave communication.

• Medium wave communication.

• Short wave communication.

• Microwave communication.

4. Classification by modulation method

• Baseband transmission: refers to a communication method in which the signal is directly sent to the channel for transmission without modulation.

• Frequency band transmission: refers to a communication method in which the signal is modulated and then sent to the channel for transmission, and the receiving end has corresponding demodulation measures.

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

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

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

• The so-called half-duplex communication method refers to a working method in which both communicating parties can send and receive messages, but cannot send and receive messages at the same time. Walkie-talkies, transceivers, etc. are all such communication methods.

• The so-called full-duplex communication refers to a working method in which both communicating parties 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 telephones, mobile phones, etc.

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