Some technical terms about mobile phones

Problem description:

I want to know some technical terms about mobile phones, and I hope you can give me some advice.

Analysis:

Built-in digital camera:

Built-in digital camera is the configuration standard of a new generation of color screen mobile phones, with built-in CCD (Photocharge Coupled Device). Industry standards for digital cameras are adopted, mainly including zoom lens, degree rotation, aperture setting, pixels, etc.

Digital cameras built into mobile phones generally use the display screen of mobile phones to display images and the memory of mobile phones to save data. Generally, color screen mobile phones with built-in digital cameras require high-resolution camera lenses with image transmission and various information functions.

Take Nokia 7650 as an example: The user only needs to push out the keyboard of the mobile phone, press the "Menu" button on the left side of the panel, and then select "Camera" in the function list through the navigation key, and the mobile phone will enter the camera mode, and the image in the lens will be automatically displayed on the screen, which will change with the movement of the lens. At this time, all you have to do is capture the wonderful picture, and then press the "shutter" (navigation key), and a unique photo will appear on your mobile phone screen immediately.

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2.5G:

2.5G mobile communication technology is a connection technology from 2G to 3G. Because 3G is a huge project, involving many and complicated layers, it is impossible to connect from the current 2G to 3G at once, so there is a 2.5G between 2G and 3G. Technologies such as HSCSD, WAP, EDGE, Bluetooth and EPOC are all 2.5G technologies. Personal digital cellular system: Personal digital cellular system-a digital mobile phone system with Japanese standards, with working frequencies of 800MHZ and 1500MHz.

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3G:

3G is the abbreviation of the third generation, which refers to the third generation mobile communication. The first generation of mobile communication is analog wireless network, and the second generation is GSM and CDMA which are widely used at present. 3G will have a wider bandwidth, with a minimum transmission speed of 384K and a maximum transmission speed of 2 M. It can transmit not only voice but also data, thus providing fast and convenient wireless applications, such as wireless access to Inter. 3G is still in the experimental stage and is expected to be fully operational in 2002. The transition technology from the second generation mobile communication to the third generation mobile communication is GPRS.

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Infrared Data Association:

Infrared data association is the configuration standard of a new generation of mobile phones, which supports data exchange between mobile phones and computers and other digital devices. Infrared communication has the characteristics of low cost, convenient connection, simple use and compact structure, so it has been widely used in small mobile devices. Through infrared data association, various mobile devices can exchange data freely.

Infrared ray is an electromagnetic wave with a wavelength between 750mn and 1mm, and its frequency is higher than that of microwave and lower than that of visible light, which is invisible to human eyes. Because of the short infrared wave length, it has poor diffraction ability to obstacles, and is more suitable for point-to-point linear data transmission that requires short-distance wireless communication. Infrared Data Association (IRDA) limits the wavelength range of light waves used in infrared data communication to 850 nm to 900 nm.

For example, it is very simple to surf the Internet wirelessly with a mobile phone equipped with infrared data association. You can surf the Internet directly as long as the infrared connection protocol is set.

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Personal identification number:

PIN code is a 4-digit to 8-digit personal input password. Only when the user enters this code can your mobile phone access the data of the SIM card. If the user enters the wrong PIN code three times in a row, the SIM card will be blocked. This situation must be re-initialized by the telecommunications department before it can be used. Don't tamper with it yourself, or you may lose more than you gain.

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Bluetooth What is Bluetooth?

Bluetooth is a short-range wireless communication technology. Electronic devices can be connected to each other through Bluetooth, and traditional wires are useless here. Through the wireless receiver on the chip, electronic products equipped with Bluetooth technology can communicate with each other within ten meters, and the transmission speed can reach 1 megabyte per second. In the past, the transmission technology in infrared data association needed the distance of electronic wires in sight. Now, with Bluetooth technology, such troubles can be eliminated.

"Bluetooth" plans to build a personal wireless local area network within the range of 10 to 100 meters, which can accommodate at least 8 small networks with uplink and downlink speeds of 432Kbps. However, when using asymmetric mode, the uplink and downlink speed will be increased to 72 1Kbps, and will be extended to 2Mbps in the future, thus improving the wireless communication capability of computers and mobile phones. Bluetooth will replace infrared rays with higher frequency (2.4GHz), with higher transmission rate and wider application range, which can meet the requirements of the future broadband network era.

According to SIG plan, the biggest development goal of Bluetooth in the future is to enable all mobile devices to send and receive information. These products mainly include:

1. Mobile communication products: mobile phones.

2. Mobile computer products: notebook computers and PDA.

3. Computer peripheral products: digital cameras, headphones, keyboards, mice and projectors.

4. Network products: Ethernet, servers, etc.

5. Household appliances: TV sets, game machines, audio-visual players, refrigerators, microwave ovens, etc.

At present, almost all digital products closely related to our lives can be within the planning scope of Bluetooth in the future.

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Lithium ion battery:

Lithium ion battery. The positive electrode is lithium ion metal oxide, the negative electrode is carbon, and the electrolyte is organic solvent. The voltage of single battery is 3.6v, which has no memory effect, and its weight and energy density are higher than that of Ni-MH battery. Therefore, under the same capacity, it has lighter weight and lower self-effect power. However, due to the high manufacturing cost, the price is higher. Moreover, due to the high energy density, the electrolyte is a flammable organic solvent, which may lead to the danger of combustion and explosion, so the requirements for charging are more stringent.

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Nickel-hydrogen battery:

That is, nickel-hydrogen battery. The anode is nickel hydroxide, the cathode is hydrogen storage alloy and the electrolyte is potassium hydroxide solution. The voltage of a single battery is 1.2v (volts). Therefore, a 3.6v or 6v mobile phone battery connected in series with 3-5 Ni-MH batteries has a slight memory effect. Compared with lithium battery, it has lower price, higher safety and simpler control required for charging and discharging.

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TFT screen:

TFT(Thin Film Transistor) is the abbreviation of thin film transistor, which belongs to a kind of active matrix liquid crystal display. It can "actively" control each independent pixel on the screen, which can greatly improve the reaction time. Generally, the reaction time of TFT is relatively fast, about 80 milliseconds, and the viewing angle is large, which can generally reach about 130 degrees, and it is mainly used in high-end products.

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UFB LCD screen:

In March 2002, Samsung released a new mobile phone LCD device called UFB LCD, which has the characteristics of ultra-thin and high brightness. UFB-LCD is a display screen specially designed for mobile phones and PDA. With ultra-thin and high brightness, it can display 65536 colors, reaching the resolution of 128 x 160. The display screen also adopts a special grating design, which can reduce the pixel spacing and get better picture quality.

The contrast of UFB LCD screen is twice that of STN LCD screen, and its brightness is equivalent to that of TFT display screen at 65536 colors, but its power consumption is less than that of TFT display screen, and its price is similar to that of STN display screen. It can be said that the combination of the advantages of these two existing products makes the multifunctional mobile phone with super-large color LCD screen closer and closer to us.

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Mobile video on demand:

Video on Demand: VOD is an interactive multimedia video on demand. With the development of computer technology and network communication technology, it is a comprehensive technology combining computer technology, communication technology and television technology. It uses the advantages of network and video technology to completely change the passive way of watching programs in the past, realize on-demand viewing and arbitrary playing of programs, and integrate dynamic video images, static pictures, sounds, words and other information to provide users with real-time, interactive and on-demand services.

Mobile video-on-demand refers to the way that information is transmitted through the mobile network, and users can independently order programs through color screen mobile phones. Mobile video-on-demand needs the support of 2.5G and 3G communication networks and high-profile color screen mobile phones.

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WCDMA:

WCDMA (Wideband Code Division Multiple Access): WCDMA originated from the integration of various technologies in Europe and Japan. WCDMA adopts direct spread spectrum (MC) mode, with carrier bandwidth of 5MHz, and data transmission can reach 2Mbit (indoor) and 384Kbps (mobile space) per second. It adopts MC FDD duplex mode and has good compatibility and interoperability with GSM network. As a new technology, it is not as mature as CDMA2000, but its advantage is that the widespread adoption of GSM can bring convenience to its upgrade. So it has been favored by major manufacturers recently. WCDMA adopts the latest asynchronous transfer mode (ATM) microcellular transmission protocol, which allows more voice calls to be transmitted on one line, and the number of calls has increased from the current 30 to 300. In densely populated areas, lines will no longer be easily blocked.

In addition, WCDMA also adopts adaptive antenna and microcell technology, which greatly improves the system capacity.

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Color scale:

Color scale is an index standard to express the brightness of display, which is what we call color index. The color fullness and fineness of the display screen are determined by the color scale. Industry standards are 256 colors, 4096 colors and 65536 colors. The color scale of color screen mobile phone is improved by 16 times.

At present, the color scale index of color screen mobile phones can be divided into three grades from low to high, and the lowest is 256 colors, such as waveguide GC600 and Ericsson T68. Followed by 4096 colors, such as Eastcom EG860, Motorola E360, Samsung T 108, etc. At present, the best color in China is 65536, and there are mainly Samsung T208, Daxian D3 100 and Lenovo I 188 in the market. 65536 color, commonly known as 16 true color, has fully met our naked eye recognition needs.

The display screen with color gradation flashes many times, and the difference of color gradation is displayed by the sum of the generated light quantity. For example, when the pixel is on, eight sub-field images with pulses of 1 (= 20), 2 (= 2 1) and 4 (= 22) can reach 128 (= 27). At this time, 1 field images obtained by combining the on/off of each subfield image can generate a total of 0? 255, that is to say, 256 color levels can be displayed.

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EMS enhanced audio-visual short message:

EMS: (enhanced short message service) enhanced short message service. Compared with SMS, the advantage of EMS is that it can not only send short text information like SMS, but also send simple information such as images, sounds and animations. EMS is a transitional technology, from SMS text information to MMS multimedia information.

As long as different brands of mobile phones support EMS, they can transmit EMS pictures to each other.

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MMS:

(Multimedia messaging service) Multimedia messaging service. WAP (Wireless Application Protocol) is a carrier for transmitting video, pictures, sounds and words. At present, operations around the world have launched this business one after another. User-created content can be transmitted automatically and quickly. It mainly addresses and locates through the telephone number of the receiver, so that MMS communication can be carried out between terminals. At the same time, MMS also supports email addressing, so information can be transmitted between the terminal and email.

MMS is the "third generation short message service" after SMS and EMS. SMS can only send and receive text messages. EMS can add * * *, simple graphics and simple animations to text messages. MMS greatly expands the types of media that can be sent and received. Words, simple pictures and * * * are natural, and complex pictures, such as photos, big charts, music clips and video clips, are the places where MMS comes into play.

At present, China Mobile's "MMS" service is open to GSM mobile phone users, and 0.9 yuan.

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KJAVA:

The so-called KJAVA can cooperate with the current JAVA environment and let programmers switch between different platforms. JAVA is a technology that has been widely used in interactive web design before the project. Because JAVA can be used on different machines, it can also be applied to other electronic products.

The built-in KJAVA programming language allows users to download games, video games and cartoon pictures from remote servers to mobile phones through the Internet. Coupled with data transmission, "downloading" services and updating data will be very easy. Starting from the second half of 200 1, mobile phones with built-in KJAVA programming language will be launched one after another, with JAVA programming ability, which is also an important symbol of information technology development ability.

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What is CDMA?

Cde code division multiple access (CDMA), also known as code division multiple access, is a technology for wireless communication. CDMA allows all users to use all frequency bands at the same time, treating signals sent by other users as noise, regardless of signal collision.

The advantages of CDMA include:

The speech coding technology provided by CDMA is superior to that provided by GSM, which can reduce the noise in the surrounding environment when users talk and make the conversation clearer.

CDMA adopts spread spectrum communication technology, so it can reduce the interference between mobile phones and increase the capacity of users. Moreover, the power of the mobile phone can be relatively low, which can not only make the use time longer, but also reduce the harm of electromagnetic radiation to people.

The bandwidth of CDMA can be greatly expanded and images can be transmitted, which is why the third generation mobile phone chooses CDMA. As far as security performance is concerned, CDMA not only has a good authentication system, but also greatly enhances the anti-eavesdropping ability by using code division multiplexing due to its transmission characteristics.

At present, CDMA system is developing rapidly.

Wideband code division multiple access (WCDMA) broadband code division multiplexing transmission technology is an important basic technology of IMT-2000, which will become the standard of the third generation digital wireless communication system.