Introduction to the basics of radio, what is the principle of radio?

Radio principle: Radio technology is through radio waves.

The technology of propagating signals. The principle of radio technology is that a change in the intensity of the current in a conductor produces radio waves.

When an electric wave travels through space to the receiving end, the electromagnetic field caused by the radio wave.

The change, in turn, creates an electric current in the conductor. The purpose of information transmission is achieved by extracting the information from the current change through demodulation.

Radio refers to electromagnetic waves that propagate in all free spaces, including air and vacuum.

It is a limited frequency band in which the lead envy, the upper frequency is at 3thz (terahertz, the lower limit frequency is less uniform, in various radio frequency specification books, the common is 3kHz 3thz (ITU International Telecommunication Union.

stipulated), 9khz 3thz, 10khz 3thz.

The main uses of radio:

1. Communication. Wireless communication occupies an extremely important position in modern communication, and wireless communication is used in almost any field, including commercial, meteorological, financial, military, industrial, civil, etc. We can see that there are many types of wireless communication systems in terms of communication systems, modulation methods, multiple access methods, etc.

2. Navigation. All satellite navigation systems use satellites equipped with precise clocks. Navigation satellites broadcast their position and timing information.

The receiver receives signals from multiple navigation satellites at the same time. The receiver calculates the distance from each satellite by measuring the propagation time of the radio wave, and then calculates its precise position.

3. Radar. Radar calculates the distance to a target by measuring the delay of reflected radio waves. and sensing the type of surface of the target by the polarization and frequency of the reflected wave. Navigation radars use ultra-short waves.

Scan the target area. The general frequency of scans is two to four times per minute, and the terrain is determined by reflected waves. This technology is commonly used on merchant ships and long-haul commercial aircraft.

4. Increase the amount of excitement and heat.

Microwave oven. High-power microwaves are used to heat food. (Note: A common misconception is that microwave ovens use frequencies for water molecules.)

, when in fact the frequency used is about one-tenth of the resonance frequency of water molecules. ）

5. Power transmission.

Japanese scientists have proposed to build large-scale solar power plants in space to convert electrical energy into microwaves and send them back to Earth.

Hello

Radio refers to transmission in free space, including air and vacuum.

1. Wireless communication is the use of BAI radio wave signals can be used.

Du free zhi

It is a communication method for information exchange based on the characteristics of spatial propagation. The wireless communication realized in the capacitance movement is also commonly known as mobile communication, and people call the two together wireless mobile communication. To put it simply, wireless communication is a communication method that uses only electromagnetic waves and does not pass through cables.

The electrical signal travels from the transmitter to the antenna, which then emits the signal into the air as a series of electromagnetic waves, and the signal travels through the air until it reaches the target location. At the target location, another antenna receives the signal, and a receiver converts it back into current.

2. Radio communication is a communication mode that modulates the sound, text, data, image and other electrical signals that need to be transmitted to each other through space and the ground on radio waves, and uses radio electromagnetic waves to transmit information in space.

Wireless incoming calls:

Radio refers to electromagnetic waves that propagate in free space, including from air and vacuum, and is one of them

A limited frequency band, the upper DAO limit frequency is 300GHz (GHz), the lower limit frequency is less uniform, in various RF specifications, the common ones are 3kHz 300GHz (ITU International Telecommunication Union regulations), 9kHz 300GHz, 10kHz 300GHz.

Principles of radio technology:

A change in the strength of the current in a conductor produces radio waves. Using this phenomenon, information can be loaded on top of radio waves by modulation. When the radio wave travels through space to the receiver, the change in the electromagnetic field caused by the radio wave will generate an electric current in the conductor.

The purpose of information transmission is achieved by extracting the information from the current change through regulation.