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how_smartphones_communicate_using_wireless [2013/06/05 11:25] (現在)
marla49 created
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 +How Wireless Works 
  
 +In the modern age of digital electronics, wireless use of different products are expected. If you get Smartphone you'll notice that it uses this same kind of technology, but how does this work? Here is an explanation of the entire bluetooth secret [[http://www.handheldgpsnavigatorsite.com/|tumbshots]] . 
 +
 +Wireless devices will usually operate at 2.4 GHZ 
 +
 +In-the permit free, internationally available ISM radio 
 +
 +band. The bonus to this band includes worldwide 
 +
 +Access and compatibility [[http://www.handheldgpsnavigatorsite.com/|garmin 60csx]] vv. A downside to 
 +
 +this however, is the fact that the units must share this 
 +
 +band with other RF emitters. This consists of 
 +
 +Auto protection methods, other wireless devices, 
 +
 +and other sound sources, including microwaves. 
 +
 +To overcome this problem, Bluetooth uses a 
 +
 +fast fre-quency hopping scheme and therefore uses 
 +
 +Smaller packets than other requirements within the 
 +
 +ISM band. This system helps to make Bluetooth 
 +
 +Interaction more strong and more secure. 
 +
 +Fre-quency moving 
 +
 +Frequency hopping is basically leaping from consistency 
 +
 +to frequency within the ISM radio group. After a 
 +
 +bluetooth unit sends or receives a supply, it 
 +
 +and the unit (or devices) it's speaking with 
 +
 +Jump to another frequency prior to the next box is 
 +
 +sent. This system provides three advantages: 
 +
 +1. Allows Bluetooth devices to make use of the 
 +
 +Whole of the available ISM group, while never 
 +
 +transmitting from a fixed fre-quency for greater than a 
 +
 +short period of time. This helps insure that 
 +
 +Bluetooth conforms to the ISM restrictions on-the 
 +
 +Indication volume per fre-quency. 
 +
 +2. Ensures that any disturbance won't 
 +
 +last long. Any package that will not arrive safely 
 +
 +to its destination could be resent to another 
 +
 +Fre-quency. 
 +
 +3. Provides a base amount of safety as 
 +
 +It is extremely hard for an eavesdropping device to predict 
 +
 +which frequency the Bluetooth devices uses 
 +
 +next. 
 +
 +The attached devices but, must agree upon the 
 +
 +Fre-quency they will use next. The specification 
 +
 +in Bluetooth ensures this in two ways. First, it 
 +
 +defines a master and servant typ-e relationship between 
 +
 +bluetooth devices [[http://www.handheldgpsnavigatorsite.com/my-garmin-60csx-review/|garmin 60csx review]] . Next, it specifies an algorithm 
 +
 +that uses device-specific information when 
 +
 +Determining the frequency hop sequences. 
 +
 +A Bluetooth device that operates in master mode could 
 +
 +Talk to up to eight devices which are set in 
 +
 +slave mode. To each of the slaves, the master 
 +
 +Bluetooth device will send its own unique address 
 +
 +and the value of its internal clock. The 
 +
 +information sent is then used to estimate the 
 +
 +frequency hop sequences. 
 +
 +Because all the slave and the master system 
 +
 +Units use the same protocol with the same initial 
 +
 +Feedback, the connected devices will always occur 
 +
 +together in the frequency that they have decided 
 +
 +upon. 
 +
 +As a substitute for cable technology, it is no 
 +
 +wonder that Bluetooth devices usually are battery 
 +
 +powered, including battery powered and wireless mice 
 +
 +Cellular phones. To store the power, most units 
 +
 +operate in low energy. It will help to provide Bluetooth 
 +
 +Products a selection of around 5 - 10 yards. 
 +
 +This range is far enough for wireless communication 
 +
 +but close enough in order to avoid drawing a lot of energy 
 +
 +from the power source of these devices.
how_smartphones_communicate_using_wireless.txt · 最終更新: 2013/06/05 11:25 by marla49