Mobile phone (mobile phone)

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mobile phone, the full name of which is mobile phone, is usually called mobile phone. Originally, it was just a communication tool. In the early days, it was also commonly known as

A, which can be used in a wide range. It was developed from the battlefield aircraft made in 1940.

in 1958, Leonid kupriyanovych invented the type of mobile cable, and Martin Cooper, an American Motorola engineer, invented the world’s first commercial mobile phone. After 2G era, 3G era, so far it has developed to 4G era, and 5g era is also closely followed, 5g commercial has appeared in China.

after several snows, the temperature in the North has continued to drop, even to minus 10 degrees. As the temperature drops, in addition to making people’s body become stiff, many mobile phone users find that their mobile phones seem to be “cold”, and turn off automatically. What’s going on here?

the smart phone uses lithium battery. Its normal working temperature is 0 ~ 40 ℃, and the limit is – 20 ~ 70 ℃. When the temperature of the battery is too low, its low temperature protection will start, but the battery has electricity but can not be released. When the temperature difference between indoor and outdoor is too large, the water vapor condenses to the mobile phone and enters the main board of the mobile phone. Therefore, the mobile phone will suddenly shut down or crash.

lithium ion polymer batteries are mostly used in electronic products on the market. Most lithium batteries are equipped with low temperature protection. The higher the battery capacity, the higher the protection level. When the temperature is too low, the metal lithium in the battery will deposit and no chemical reaction will occur.

A and non smart phones, the performance of general smart phones is better than that of non smart phones, but the performance of non smart phones is more stable than that of smart phones. Most non smart phones and smart phones use the CPU of the company architecture. Smart phones have higher main frequency, faster running speed, faster processing tasks, and more convenient daily (for example, the main frequency of Nokia N81 is 369 MHz); while the main frequency of non smart phones is relatively low and the running speed is relatively slow (for example, the main frequency of Nokia 5000 is 50 MHz).

smart phones refer to independent operating systems like personal computers. Most of them are large screen machines, and some are resistance screens, which are powerful and practical. Users can install programs provided by third-party service providers, such as games, by which the functions of mobile phones can be continuously expanded, and wireless network access can be realized through mobile communication networks. It is a simple formula of “1 + 1 =” and “PDA + mobile phone = smart phone”. In a broad sense, smart phones not only have the call function of mobile phones, but also have most of the functions of PDA, especially personal information management and browser and email functions based on wireless data communication. Smart phones provide users with enough screen size and bandwidth, which is not only convenient to carry, but also provides a broad stage for software operation and content services. Many value-added services can be launched in this way, such as stock news, weather, transportation commodity application download, music pictures, game download, etc.

if we trace back, we will find that the concept of mobile phone appeared as early as the 1930s. At that time, Bell Labs, the largest communication company in the United States, began to trial produce it. In 1930, Bell Labs made the first so-called mobile phone. However, due to its large size, the researchers can only put it on the shelf of the laboratory, and gradually people forget.

in April 1973, Martin Cooper, a famous American Motorola Company, invented the world’s first mobile phone for civilian use. When Cooper made the world’s first mobile phone, he could use any electromagnetic band. In fact, the first generation of analog mobile phones was based on different frequencies to distinguish different mobile phones of different users. The second generation of mobile phone, GSM system, distinguishes users by extremely small time difference. Nowadays, the frequency resources are obviously insufficient, and the mobile phone users are growing rapidly in geometric progression. As a result, the new CDMA technology, which distinguishes different machines by different codes, emerges as the times require. The mobile phone with this technology not only has better communication quality and confidentiality, but also can reduce radiation, which can be called “green mobile phone”.

in 1832, Faraday in England discovered the phenomenon of electromagnetic induction. Maxwell further elaborated the research results of Faraday and others with mathematical formula, and extended the electromagnetic induction theory to space. More than 60 years later, Hertz confirmed the existence of electromagnetic waves in the experiment. The discovery of electromagnetic wave has become the turning point from cable communication to radio communication, and also the origin of the whole mobile communication. As a scientist said, mobile phones were born on the shoulders of telegrams and telephones. Without previous efforts, wireless]

a. Morse’s telegraph machine sent the first telegram of human history from Washington to Baltimore. What a miracle God created!

on June 2, 1875, bell accidentally splashed sulfuric acid on his leg while doing experiments. He yelled to his colleagues in another room in pain. Help me! And this sentence was passed through the experimental telephone to the Walter who answered the phone in another room. It became the year of the wire. An American named Nathan stubbfield built the first wireless telephone device in a rural house in Murray, Kentucky, which can be moved wirelessly The telephone of communication is the earliest exploration and research of “mobile phone” technology

in 1940, Bell Laboratories of the United States made the year of mobile wire for war. The first year of mobile wire for telephone was made from a moving car in St. Louis, engineer Leonid. Kuprijanovich invented the type of the mobile wire, the model of the model, and he has made further improvements to his mobile phone. The weight of the device has been reduced from 3 kg to 500 g (including battery weight), and its shape has been reduced to the size of two cigarette packs. It can be dialed anywhere in the city and can be connected to any fixed wire. Early this year, kupriyano In 1958, the Soviet Union began to develop the world’s first fully automatic mobile phone communication system “Altay” (a  888)

in 1973, a man stood on the street of New York, pulled out a wireless phone about the size of a brick, and began to talk.

this man is the inventor of the mobile phone, Martin Cooper. At the time, he was an engineer at Motorola. This was the first mobile wire year in the world at that time. The Federal Communications Commission (FCC) determined the spectrum of terrestrial mobile phone communication and large capacity cellular mobile phone. In 1979, Japan opened the world’s first cellular mobile wire year, and Europe established GSM (mobile communication task force).

in 1985, the first modern commercial mobile phone was born. It is a power antenna placed in an example, weighing up to 3 kg.

mobile phones that are similar to modern shapes were born in 1987. It still weighs about 750 grams, which is like a big brick when compared with today’s 60 gram cell phone.

at present, the so-called fourth generation mobile phone (4G) is widely used in the world. The fdd-lte system in Europe and America and TD-LTE in China are the main ones. Based on 3G communication technology, 4G communication technology is continuously optimized, upgraded and innovated. It integrates the advantages of 3G communication technology and derives a series of inherent characteristics, with WLAN technology as the development focus. Compared with 3G communication technology, 4G communication technology has more competitive advantages. First of all, 4G communication can realize high-definition transmission of original picture and original video in picture and video transmission, and its transmission quality is similar to that of computer image; secondly, using 4G communication technology, the speed of downloading software, files, pictures, audio and video can reach up to several 10 megabits per second, which is not realized by 3G communication technology, but also a significant advantage of 4G communication technology This fast download mode can bring us a better communication experience and facilitate the download of learning materials in our daily study. At the same time, in the context of the rapid and convenient development of the network, users also put forward higher requirements for the traffic cost. From the current 4G network communication charges, the price is lower, and the transition to 5g.

industry insiders believe that although the basic protection functions of mobile phone security products are relatively complete, there are still deficiencies in anti-interference, privacy protection and data protection, and there is still a large market space in the future. Security manufacturers such as QQ mobile phone housekeeper security housekeeper net Qin have announced to enter the cloud security field. 2013 will be a key year for the rapid landing of mobile cloud security All manufacturers will continue to increase investment in mobile cloud security solutions.

the first generation mobile phone (1g) refers to the simulated mobile wire. In the 1980s and 1990s, China, Hong Kong, the United States and other film and television works appeared. Dr. Cooper of the United States was the first to develop a mobile phone. Due to the limitation of battery capacity and the development of analog modulation technology, such as large antenna and integrated circuit, this kind of mobile phone can only be mobile, not portable. Many people call this kind of mobile phone “brick” or “Black King Kong”.

this kind of mobile phone has a variety of formats, such as nmtampstats. But basically, frequency division multiplexing can only be used for voice communication. The receiving effect is unstable, and the confidentiality is insufficient, and the wireless bandwidth is not fully utilized. This kind of mobile phone is similar to a simple radio duplex radio station. The call is locked at a certain frequency, so the use of FM radio can eavesdrop on the communication line. G) is also the most common mobile phone. Usually these mobile phones use GSM or CDMA, which are very mature standards, with stable call quality and appropriate standby time. In the second generation, in order to meet the needs of data communication, some intermediate standards are also supported on mobile phones, such as GPRS for MMS service, WAP service for Internet service, and various Java programs.

some mobile phone manufacturers call some of their mobile phones as 2.5G mobile phones, which are characterized by GPRS function.

some mobile phone manufacturers also call some of their mobile phones as 2.75g mobile phones, which are characterized by edge function faster than GPRS. Compared with the first generation analog mobile phone (1g) and the second generation digital mobile phone (2G), the third generation mobile phone generally refers to a new generation of mobile communication system which combines wireless communication with multimedia communication such as Internet. It can process image, music, video stream and other media forms, and provide a variety of information services including web browsing, teleconference, e-commerce and so on. That is to say, it can support at least 2Mbps (megabits per second), 384kbps (kilobits per second) and 144kbps in indoor, outdoor and driving environments respectively.

ITU stipulates that 3G mobile phone is IMT-2000 (International Mobile wire) standard

Author: zmhuaxia