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how_smartphones_speak_using_bluetooth [2013/06/05 11:25] (現在)
kevin687 created
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 +How Wireless Works 
  
 +Within the modern age of digital electronics, instant usage of different devices are inevitable. Should you buy Smartphone you'll realize that it uses this same sort of technology, but how can this work? Here's a description of the whole bluetooth mystery [[http://www.handheldgpsnavigatorsite.com/|what to look for when buying a handheld gps]] . 
 +
 +Bluetooth devices will typically operate at 2.4 GHZ 
 +
 +in the license free, globally available ISM radio 
 +
 +band. The bonus to the band contains world wide 
 +
 +availability and compatibility [[http://www.handheldgpsnavigatorsite.com/|garmin 62s article]] vv. A downside to 
 +
 +this but, is that the units must share this 
 +
 +band with other RF emitters. Including 
 +
 +Auto protection programs, other wireless devices, 
 +
 +and other sound sources, including microwaves. 
 +
 +To overcome this challenge, Bluetooth uses a 
 +
 +fast frequency hopping scheme and consequently uses 
 +
 +shorter packages than other standards within the 
 +
 +ISM band. This structure helps you to make Bluetooth 
 +
 +Connection more strong and more secure. 
 +
 +Consistency jumping 
 +
 +Frequency hopping is basically getting from consistency 
 +
 +to consistency within the ISM radio band. After having a 
 +
 +bluetooth system sends o-r receives a packet, it 
 +
 +and the unit (or devices) it's speaking with 
 +
 +hop to a different frequency ahead of the next packet is 
 +
 +sent. This scheme provides three advantages: 
 +
 +1. Allows Bluetooth devices to make use of the 
 +
 +entirety of the available ISM group, while never 
 +
 +Shifting from the fixed fre-quency for more than a 
 +
 +Little while of time. This can help insure that 
 +
 +Bluetooth conforms to the ISM restrictions to the 
 +
 +Indication sum per fre-quency. 
 +
 +2. Means that any disturbance won't 
 +
 +last long. Any packet that will not arrive safely 
 +
 +to its destination may be resent to another location 
 +
 +Fre-quency. 
 +
 +3. Provides a base level of safety as 
 +
 +It is rather difficult for an eavesdropping device to anticipate 
 +
 +which fre-quency the Bluetooth devices will use 
 +
 +next. 
 +
 +The related devices but, must agree upon the 
 +
 +frequency they will use next. The specification 
 +
 +in Bluetooth guarantees this in two ways. First, it 
 +
 +Describes a master and servant type relationship between 
 +
 +Wireless units [[http://www.handheldgpsnavigatorsite.com/my-garmin-60csx-review/|garmin 60csx review]] . Next, it describes an algorithm 
 +
 +that uses device specific information when 
 +
 +Establishing the fre-quency hop sequences. 
 +
 +A Bluetooth device that operates in master mode may 
 +
 +Talk to around eight units which are set in 
 +
 +slave mode. To each one of the slaves, the master 
 +
 +Wireless device can send its unique address 
 +
 +and the value of a unique internal clock. The 
 +
 +information delivered is then used to estimate the 
 +
 +Fre-quency hop sequences. 
 +
 +Because the master unit and all the slave 
 +
 +Units utilize the same protocol with the same initial 
 +
 +input, the connected devices will often arrive 
 +
 +together at the fre-quency that they have decided 
 +
 +upon. 
 +
 +As a substitute for wire technology, it is no 
 +
 +wonder that Bluetooth devices are usually battery 
 +
 +powered, for example wireless rats and battery powered 
 +
 +Cell-phones. To save the ability, most units 
 +
 +Function in low energy. This can help to give Bluetooth 
 +
 +Units a variety of around 5 - 10 meters. 
 +
 +This variety is far enough for instant communication 
 +
 +but close enough to prevent drawing too much energy 
 +
 +In the power supply of the unit.
how_smartphones_speak_using_bluetooth.txt · 最終更新: 2013/06/05 11:25 by kevin687