UEFA live free

List of the table of contents of this article:

• 1. What are the components of the wireless communication system of insulated special vehicles?
• 2, What are the classifications and characteristics of modern satellite communication systems?
• 3, Mobile Classification of communication system
• 4、 How to classify the communication system according to the characteristics of the transmission signal?
• 5, How to classify the communication system according to the physical characteristics of the message?

What parts does the wireless communication system of insulated special vehicles consist of?

Wireless Communication System: Also known as radio communication system, it is composed of three major parts: transmitting device, receiving device and wireless channel. It uses wireless electromagnetic waves to realize information and data transmission. System.

Wireless communication systems are generally composed of senders, receivers and their connected antennas (including feeders).

The communication system is roughly composed of three parts: the transmitter (sending source and sending device), the channel receiving device (the receiving device), and the noise source. The source is the source of information, and its function is to convert the original signal into the corresponding electrical signal, that is, the baseband signal.

What are the classifications and characteristics of modern satellite communication systems?

In the earth station part, the main common is satellite communication antenna. According to the different requirements of the use environment, it can be divided into dynamic communication antenna, static communication antenna and portable station antenna.

From the perspective of terrestrial stations, satellite communications can also be divided into fixed service communication, mobile service communication and broadcast service communication. In addition, there are more classifications from business applications, such as data acquisition interaction, military communication, emergency communication, IP network communication, etc.

Compared with other communication methods, satellite communication has the following characteristics: 1. The communication distance is long, and the cost has nothing to do with the communication distance. It can be seen from Figure 12 that the maximum communication distance of geostationary satellites is about 18,100km.

According to the working orbit, satellite communication systems are generally divided into the following three categories: Low-orbit satellite communication system (LEO): 500-2000Km above the ground, the transmission delay and power consumption are relatively small, but the coverage of each star is also relatively small. Typical systems include Motorola's Iridium system.

Satellite communication has a long communication distance, and the cost of station construction has nothing to do with distance. Except for the two poles of the earth, station communication can be built. The network is flexible and convenient for multi-address connection. Good mobility, stable and reliable quality of communication lines. Communication frequency bandwidth, large transmission capacity, suitable for a variety of service transmission, can be monitored spontaneously and monitored.

Satellite communication systems usually consist of two parts, namely the satellite end and the ground end. The satellite end is in the air, which is mainly used to amplify and forward the signals sent by the ground station to other ground stations. Ground stations are mainly used to control and track satellites and realize ground communication system access to satellite communication systems.

Classification of mobile communication system

Classification of mobile communication system can be classified according to its application.The maritime satellite mobile system is mainly used to improve maritime rescue work, improve the efficiency and management level of ship use, and enhance maritime communication services and wireless positioning capabilities.

Special mobile communication; according to the activity range of the mobile station, there are land mobile communication, sea mobile communication and aviation mobile communication; according to the usage, the commonly used are mobile phone, wireless paging, cluster dispatch system, leakage cable communication system, cordless telephone, centerless location mobile communication system, Star mobile communication system, personal communication.

Mobile communication is a communication method used to communicate between mobile users and fixed-point users or between mobile users. One or both parties to the communication are in motion. Mobile communication includes land, sea and air communication, and the frequency bands cover low frequency, medium frequency, high frequency, very high frequency and ultra-high frequency.

Mobile communication systems mainly include cellular system, cluster system, AdHoc network system, satellite communication system, packet wireless network, cordless telephone system, radio paging system, etc.

How to classify the communication system according to the characteristics of the transmission signal?

Communication system refers to a system formed by the organic combination of various relevant functional entities that complete the whole communication process.

According to the modulation method, the baseband transmission is divided into analog communication system, digital communication system, communication system transmission means, cable communication twisted pair, coaxial cable, etc. according to the characteristics of the transmission signal. City call and long-distance communication. Mode of modulation: SSB/FDM. Based on coaxial PCM time-multiplied digital baseband transmission technology.Optical fiber will gradually replace coaxial.

Classification of communication system According to information type Telephone communication system Data communication system Cable TV system Classification by modulation method Baseband transmission Modulation transmission According to transmission signal characteristics Analog communication system Digital communication system Communication system Transmission means Cable communication Twisted pair , coaxial cable, etc. City call and long-distance communication.

How to classify the communication system according to the physical characteristics of the message?

1. According to the physical characteristics of the message, the communication system is divided into telephone communication system, data communication system, image communication system, etc. At present, telephone communication networks are the most popular, and other messages are often transmitted through public telephone communication networks.

2. The messages transmitted by the communication system are diverse, but in terms of their characteristics, they can be divided into two categories, continuous messages and discrete messages.

3. Generally, there are several classification methods: 1. Broadband communication system and narrowband communication system according to signal bandwidth.

4. Communication refers to the transmission of information between people, places, processes and machines in accordance with the agreement reached.