Wireless communication in everyday life
Wave：
● The essence of communication is the transmission of information, mainly in the form of waves.
● Waves are divided into mechanical waves, electromagnetic waves, matter waves and gravitational waves (quantum communication).
● Animals and plants learned to use sound waves, infrared and visible light through evolutionary exploration.
electromagnetic waves:
At present, the most commonly used electromagnetic wave is actually the electromagnetic wave, which can be divided into several parts in general:
●Radio (R) (3Hz~300MHz) (TV, radio, etc.)
●Microwave (IR) (300MHz~300GHz) (radar, etc.)
●Infrared (300GHz~400THz)
●Visible light (400THz~790THz)
●UV
●X-ray
●gamma rays
Daily Application：
Bands are divided and used for different purposes, such as AM, FM, TV broadcasting, satellite communications, etc., you can refer to the official documents of specific countries.
GSM, 3G, and 4G are all microwaves.
Satellites are also microwave communications. The most suitable frequency for satellite communications is the 1-10GHz frequency band, that is, the microwave frequency band.
In order to meet more and more needs, new frequency bands have been studied and applied, such as 12GHz, 14GHz, 20GHz and 30GHz.
Huhutong is satellite TV, served by Zhongxing 9 satellite. In other words, the packaging of this live broadcast system is really powerful, just go to the official website to see it.
Satellite phones (for expeditions and ships) are already the size of a smartphone.
Bluetooth and wifi are microwaves.
Air conditioners, fans, and color TV remote controls are infrared.
NFC is radio (Near Field Communication is a short-range, high-frequency radio technology that operates at 13.56MHz at a distance of 20cm).
RFID tags (low frequency tags (125 or 134.2 kHz), high frequency tags (13.56 MHz), UHF tags (868~956 MHz) and microwave tags (2.45 GHz))