What Is a Radio Communication System?

Radio communications (radio communications) are communication methods that modulate electrical signals such as sound, text, data, and images that need to be transmitted on radio waves and transmit them to each other through space and the ground. Wireless electromagnetic waves are used to transmit information in space.

The communication method that uses "electricity" to transfer messages is called

In 1873,

The biggest charm of radio communication is that with the help of

After more than a hundred years of continuous development of classification, various new radio services are constantly emerging, and the types of radio services are increasing. in accordance with

Radio technology has been used in China for hundreds of years. As early as 1897 (

Radio business in new China

Electronic countermeasure refers to the electromagnetic spectrum fight between the two parties using electronic equipment and equipment. Electronic countermeasures are also called "electronic warfare" or "electronic struggle". Combat operations by opposing parties using electronic technology. The purpose is to weaken and destroy the effectiveness of the use of enemy electronic equipment, in order to protect the effectiveness of their own electronic equipment. Including radar countermeasures, radio communication countermeasures, and photoelectric countermeasures. The basic content is electronic countermeasure reconnaissance, electronic interference and electronic defense. Electronic countermeasures are an important means of warfare in modern warfare.

With the development of science and technology, the electronic level of the army has been rapidly improved. Aircraft, ships, satellites dedicated to electronic countermeasures, and anti-radiation missiles used to destroy radar and other devices have appeared one after another. Improved, electronic countermeasures are gradually playing an active role on the stage of modern warfare with a combat method used directly for offense and defense. The traditional land, sea, and air warfare has developed into a multidimensional, three-dimensional warfare that includes space and electricity. Electronic countermeasures, which are characterized by a kind of "soft killing," run through the entire course of the war.

Electronic countermeasures (ECM-Electronic countermeasures), the United States and NATO countries are called "electronic warfare", Russia is called "electronic struggle". Electronic countermeasure technology mainly refers to the use of special electronic equipment, instruments and electronic strike weapon systems to reduce or destroy the operating efficiency of enemy electronic equipment, while protecting the normal performance of their electronic equipment. Electronic Warfare

The basic means are electronic reconnaissance and anti-reconnaissance, electronic interference and anti-interference, anti-radiation destruction and anti-destroy. The main contents of electronic countermeasures include: electronic reconnaissance, electronic attack, and electronic defense. The essence of electronic confrontation is the struggle between the enemy and us for the control of the electromagnetic spectrum (that is, the right to control the electromagnetic spectrum). Electromagnetic control rights, like air control rights and sea control rights, refer to the right to control the electromagnetic spectrum within a certain range of time and space. The seizure of electromagnetic control rights means that oneself can use the electromagnetic spectrum freely without being threatened by the other's electromagnetic force; at the same time, it deprives the other party of the right to use the electromagnetic spectrum freely. Controlling electromagnetic power has its time and space. The party that is relatively inferior in general is not at a loss. If scientific command and reasonable concentration of power can seize local electromagnetic control power in a certain time or region.

The scope of electronic countermeasures includes acoustic countermeasures, radio frequency countermeasures, and optical countermeasures (optical countermeasures) in the frequency domain. It can be divided into ground, sea, air, space and underwater. As for the equipment used, it can be divided into radio communication countermeasures, radar countermeasures, photoelectric countermeasures, and C3I system electronic countermeasures ^[2] .