Mobile phone

——

Price: Yuan1350
Add Time: 2018-06-02 17:21:14
Recommendation:


introductionIntroduction

——

Print       Small   Middle   Big

Mobile phones are divided into Smart phone ([4]) and non smart phone (Feature phone). The performance of smart phones is better than non smart phones, but non smart phones are more stable than smartphones, and most non smart phones and smartphones use the CPU of the British ARM company architecture. Smart phones have higher primary frequency, faster running speed, faster processing programs, and more convenient daily (for example: the main frequency of NOKIA N81 has 369 megahertz); instead of the smart phone, the main frequency is lower and the speed is slower (for example, NOKIA's 5000 main frequency is 50 Chz).


Smart phone (Smartphone), like a personal computer, has an independent operating system, most of them are large screen machines, and it is a touch capacitive screen, also a part of the resistance screen, powerful and practical. It can be installed by users on their own, including games, such as the program provided by the three party service providers, through such programs to continue to expand the function of the mobile phone, and can through the mobile communication network to achieve wireless network access to such a general name of the mobile phone. The popular point is a simple "1+1=" formula, "palm computer + mobile phone = smart phone". In a broad sense, in addition to the phone's call function, smart phones have most of the functions of PDA, especially personal information management and browser and e-mail based on wireless data communication. Smart phone provides users with enough screen size and bandwidth, which is convenient to carry around, and provides a broad stage for software operation and content services. Many value-added businesses can be launched, such as stock, news, weather, transportation, goods, application downloads, music picture downloads and so on [5]. If we look back, we will find that the concept of mobile phone appeared in 40s. At that time, Baer laboratories, the largest communications company in the United States, began trial production. In 1940, Baer laboratory created the first so-called mobile phone. But because the volume is too large, the researchers can only put it on the shelf of the laboratory, and slowly people forget it.


In April 1973, Martin Coop, the famous Motorola engineering technician, invented the world's first mobile phone for civilian use. When he first hits the world's first mobile phone, he can use any electromagnetic band. In fact, the first generation of analog phones distinguish the different mobile phones of different users by different frequencies. The second generation of mobile phones, the GSM system, distinguishes users by extremely small TDOA. Until now, the frequency resources have been obviously insufficient, and the mobile phone users also grow rapidly in geometric series. As a result, the updated CDMA technology, which is different from coding to distinguish different machines, arises at the historic moment. The mobile phone using this technology not only has better call quality and confidentiality, but also reduces radiation. It can be called "green cell phone".


History of development


In 1831, Faraday found electromagnetic induction in Britain. Maxwell introduced the research results of Faraday et al. And extended the theory of electromagnetic induction to space. More than 60 years later, Hertz verified the existence of electromagnetic waves in experiments. The discovery of electromagnetic waves has become the turning point of "wired communication" to "radio communication", and has also become the source of mobile communication. As a scientist has said, "mobile phones are born on the shoulders of telegraphs and telephones. Without the efforts of predecessors, wireless communication is impossible.


On AComputer
NextCamera

CommentsCOMMENT

——

User Name Name
Comments Comment
模板编号:CmsEasy_V_487 ↓  点击购买这款模板 → 查看其他几百套精美网站模板! X