Wi-Fi (Wireless Fidelity) has become a widely used short-range wireless technology with its high transmission speed, long effective distance and high compatibility. For the designer of the product, it is very important to choose the appropriate wifi chip. This article will take stock of the wifi chip and its parameters of Broadcom, TI and other manufacturers.
Wi-Fi is a technology that allows electronic devices to connect to a wireless local area network (WLAN). WIFI stands for Wireless Fidelity, also known as the 802.11 standard, and typically uses the 2.4G UHF or 5G SHF ISM RF band. Connecting to a wireless LAN is usually password protected; but it can also be open, allowing any device within the WLAN range to be connected. Wireless Fidelity is a brand of wireless network communication technology, held by the Wi-Fi Alliance. The goal is to improve interoperability between wireless network products based on the IEEE 802.11 standard.
Advantages and disadvantages of Wi-Fi technology
Advantages of WiFi technology
(1) Wide coverage of radio waves
The coverage of radio waves is wide. The coverage of radio waves based on Bluetooth technology is very small. The radius is about 50 feet or so, and the radius of Wi-Fi is about 300 feet.
(2) Fast speed and high reliability
The 802.1 lb wireless network specification is a variant of the IEEE 802.11 network specification with a maximum bandwidth of l1 Mbps. In the case of weak or interfering signals, the bandwidth can be adjusted to 5.5 Mbps, 2 Mbps and 1 Mbps. The bandwidth is automatically adjusted, effectively The stability and reliability of the network are guaranteed.
Disadvantages of WiFi technology
WiFi technology can only be used as a specific mobile WiFi technology application. Compared with a wired network, the wireless network is weakened by the distance from the node within its coverage range. The WiFi technology itself ll Mb/s The transmission speed may reach the end user's hand with only 1 M effective rate due to the increase of the distance, and the wireless signal is easily hindered by the building wall. The radio wave encounters obstacles in the process of propagation and will have different degrees of refraction. , reflection, diffraction, signal propagation is disturbed, radio signals are also susceptible to interference from the same frequency waves and lightning weather.
WiFi networks can use the frequency of wireless networks because they do not need to be explicitly applied, so the network is easily saturated and vulnerable. The security of the WiFi network is not satisfactory. 802.11 provides an encryption algorithm called WEP that encrypts data transmitted wirelessly between a network access point and a host device to prevent unauthorized users from eavesdropping, attacking, and invading the network. However, since WiFi is inherently lacking the protection of the physical structure of the wired network, and it is not necessary to connect to the network before accessing the wired network, if the network is not protected, as long as it is within the signal coverage, only the wireless network card can be accessed by others. Your network, taking up your bandwidth, causes your information to leak.
The mainstream Wi-Fi chip manufacturers include:
1, Broadcom (Broadcom, USA)
2. Atheros (Atheros, USA, acquired by Qualcomm)
3, Marvell (Meiman Technology, USA)
4. TI (Texas Instruments, USA)
5. Ralink (Raining, Taiwan, acquired by MediaTek (MTK))
6, Realtek (Rui Wei, Taiwan)
7. Shanghai Lexin
8. Beijing New Shoreline
9, Beijing Shengdewei
10. Shenzhen Southern Silicon Valley
11, Shanghai picked up
12, Shanghai Qingke (shipping WiFi module)
Lead Acid batteries (LA), usually called Acidic batteries.
Use Lead and Lead Sulphate electrodes and Sulphuric acid electrolyte.
Construction classification:
The batteries divided also into two major groups based on its construction:-
• Vented batteries, also called open batteries with removable caps.
• Sealed batteries with valve regulator, usually used for lead acid batteries (Valve Regulated Lead Acid -VRLA).
The VRLA batteries classified to AGM or Gel groups based on the electrolyte media if it is Glass mate or Silica Gel.
Abg Battery,Gel Battery,Gel Cell Battery,Gel Car Battery
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