蓝牙是一种近距离的无线传输应用技术,在10—100米范围内,把专用的半导体装入机器中,无须借助电缆就可连接计算机、打印机、数字相机、电视机、手机、微波炉等,并能同时进行数据和语音传输。是英语blue tooth的直译。下面是小编为您收集整理的什么叫蓝牙,供大家参考!


  What is Bluetooth?

  Bluetooth is a universal radio interface in the 2.45GHz frequency band that enables portable electronic devices to connect and communicate wirelessly via short-range, ad hoc networks. Each unit can simultaneously communicate with up to sever other units per piconet. Moreover, each unit can simultaneously belong to several piconets.

  What is Bluetooth Technology?

  Bluetooth technology which apart from Ericsson, has gained the support of Nokia, IBM, Toshiba, Intel and many other manufacturers.

  Eliminates the need for wires, cables and connectors for and between cordless or mobile phones, modems, headsets, PDAs, Computers, printers, projectors, local area networks, and so on, and paves the way for new and completely different devices and applications.Technology Characteristics—1Ms/s symbol rate exploits maximum available channel bandwidth.

  Fast frequency hopping avoids interference

  Adaptive output power minimizes interference

  Short data packets maximize capacity during interference

  Fast acknowledge allows low coding overhead for links

  CVSD(Continuous Variable Slope Delta Modulation)voice coding enables operation at high bit- error rates

  Flexible packet types supports wide application range

  Air interface tailored to minimize current consumption

  Basic Technical Information—Based upon a small, high performance integrated radio transceiver, each of which is allocated a unique 48-bit address derived from the IEEE 802.standard.

  Operate in the unrestricted 2.45GHz ISM free band, Which is available globally although slight variation of location and width of band apply.

  Range set at 10m to optimize for target market of mobile and business user

  Gross data rate 1Mbit/s with second generation plans to increase to 1Mbit/s

  One-to-one connections allow maximum data transfer rate of 721kbit/s (3 voice channels)

  Uses packet switching protocol based on frequency hop scheme with 1600 hops/s to enable high performance in noisy radio environments. The entire available frequency spectrum is used with 79 hops of 1Mhz bandwidth, analogous to the IEEE 802.11 standard.

  Low power consumption longevity for battery powered devices. During data transfer the maximum current drain is 30mA. However during pauses or at lower data rates will be lower.











  每一个小型、高性能、集成的无线电收发机都有IEEE 802标准所规定的一个唯一的48比特位地址

  开放的2.45GHz ISM自由频段,全球都可以自由使用。




  在无线电噪声环境里,利用基于每秒1600跳跳频表的分组交换协议可以提高系统性能。以1Mhz带宽79跳来利用这个完整的可用频谱。这类似于IEEE 802.11标准。



  Digital Wallets

  A digital wallet is software that enables users to pay for goods on the Web. It holds credit-card numbers and other personal information such as a shipping address. Once entered, the data automatically populates order fields at merchant sites.

  When using a digital wallet, consumers don't need to fill out order forms on each site when they purchase an item because the information has already been stored and is automatically updated and entered into the order fields across merchant sites. Consumers also benefit when using digital wallets because their information is encrypted or protected by a private software code. And merchants benefit by receiving protection against fraud.

  Digital wallets are available to consumers free of charge, and they're fairly easy to obtain. For example, when a consumer makes a purchase at a merchant site that's set up to handle server-side digital wallets, he types his name and payment and shipping information into the merchant's own form. At the end of the purchase, one consumer is asked to sign up for a wallet of his choice by entering a user name and password for future purchases. Users can also acquire wallets at a wallet vendor's site.

  Although a wallet is free for consumers, vendors charge merchants for wallets.

  Digital wallets come in two main types: client-side and server- side. Within those pisions are wallets that work only on specific merchant sites and those that are merchant agnostic.

  Client-based digital wallets, the older of the two types, are falling by the wayside, according to analysts, because they require users to download and install software. A user downloads the wallet application and inputs payment and mailing information. At that point, the information is secured and encrypted on the user's hard drive. The user retains control of his credit card and personal information locally.

  With a server-based wallet, a user fills out his personal information, and a cookie is automatically downloaded. (A cookie is a text file that contains information about the user.)In this scenario, the consumer information resides on the server of a financial institution or a digital wallet vendor rather than on the user's PC.

  Server-side wallets provide assurance against merchant fraud because they use certificates to verify the identity of all parties. When a party makes a transaction, it presents its certificate to the other parties involved. A certificate is an attachment to an electronic message used to verify the identity of the party and to provide the receiver with the means to encode a reply.

  Furthermore, the cardholder's sensitive data is typically housed at a financial institution, so there's an extra sense of security because financial environments generally provide the highest degree of security.

  But even though wallets provide easy shopping online, adoption hasn't been widespread.

  Standards are pivotal to the success of digital wallets.












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