The high frequency band has abundant frequency resources and large system capacity. But the higher the frequency, the propagation lossThe larger the consumption, the closer the covering distance, the weaker the diffraction ability. In addition, the higher the frequency, the greater the technical difficulty, and the cost of the system increases accordingly. The lower the frequency, the smaller the propagation loss, the farther the coverage distance, and the stronger the diffraction ability.
First of all, let's briefly understand the reasons for the slow wireless network data transmission speed, radio waves in the air is easy to be propagated by various obstacles, interference sources to interfere, which will naturally cause WLAN transmission speed slow.
Wireless transmission frequency is not related to them, and they are related to the strength of the signal of the wireless device antennaIn a transmission distance is also related to the wireless standard, the loss is the farther away the signal is weaker. The propagation distance is related not only to the transmitting frequency, but also to the transmitting power.
Latest protocol, not fully backward compatible. Transmission rate: 108Mbps-600Mbps. Transmission distance: 200 meters. A Wireless network is any type of radio computer network that is generally combined with a telecommunications network and can be connected between nodes without cables. Wireless telecommunications networks are generally used to use electromagnetic wave shakingThe device and two "magnetic devices" installed on the phone device interact and create an electric current. At present, products supporting wireless charging have appeared in mobile phones, electric vehicles, smart furniture and other fields. Among them, in the mobile phone industry, the "Qi standard" is the most common, and Qi labels are often used in the packaging of many mobile phones and wireless chargers.
Using the principle of electromagnetic induction charging equipment, the principle is similar to the transformer, by setting the coil at the transmitting end and the receiving end, the transmitting end coil sends an electromagnetic signal under the action of power, the receiving end coil receives the electromagnetic signal and converts the electromagnetic signal intoCurrent, so as to achieve the purpose of wireless charging.
Wireless charging system mainly adopts the principle of electromagnetic induction. Wireless charger refers to the charger that does not need to be connected to the terminal device that needs to be charged without the traditional charging power cord, using the latest wireless charging technology, through the use of the magnetic field generated between the coils, the magic transmission of electrical energy, inductive coupling technology will become a bridge connecting the charging base station and equipment.
Wireless charging, also known as inductive charging, non-contact inductive charging, from wireless power transmission technology, is the use of near-field induction, that is, inductive coupling, by the power supply equipment (charger) energyIt is transmitted to an electrical device, which uses the received energy to charge the battery and at the same time for its own operation.
2, wireless Modem has a variety of practical functions, the main feature is to be able to handle Chinese, English and digital SMS sending and receiving, which provides convenience for cross-language communication. SMS alarm function is especially integrated into GPRS wireless Internet access technology, providing developers with rich interface support, including VB/VC/C#/DEPHI dynamic link library DLL and matching test program, making software development and integration easier, especially suitable for the construction of SMS group software.
3, Modem refers to the modem, it is one of the most basic equipment in computer communication. The function of the Modem is to convert the digital signal into analog signal, transmit it to the remote computer through the telephone line, and then convert the analog signal into digital signal, so as to realize the data transmission between computers. The Modem made communication between computers possible and laid the foundation for the development of the Internet.