Saturday, July 14, 2012

သိသင္႕ သိထိုက္ေသာ မိုဘိုင္းဖုန္း စကားလံုးမ်ား


CPU (Central Processing Unit)
CPU (Central Processing Unit) - otherwise known as a processor - is an electronic circuit that can execute computer programs. Both the miniaturization and standardization of CPUs have increased their presence far beyond the limited application of dedicated computing machines. Modern microprocessors appear in everything from automobiles to mobile phones.
The clock rate is one of the main characteristics of the CPU when performance is concerned. Clock rate is the fundamental rate in cycles per second (measured in hertz, kilohertz, megahertz or gigahertz) for the frequency of the clock in any synchronous circuit. A single clock cycle (typically shorter than a nanosecond in modern non-embedded microprocessors) toggles between a logical zero and a logical one state.
With any particular CPU, replacing the crystal with another crystal that oscillates with twice the frequency will generally make the CPU run with twice the performance. It will also make the CPU produce roughly twice the amount of waste heat.
Engineers are working hard to push the boundaries of the current architectures and are constantly searching for new ways to design CPUs that tick a little quicker or use slightly less energy per clock. This produces new cooler CPUs that can run at higher clock rates.
Scientists also continue to search for new designs that allow CPUs to run at the same or at a lower clock rate as older CPUs, but which get more instructions completed per clock cycle.
The clock rate of a processor is only useful for providing comparisons between computer chips in the same processor family and generation.
Clock rates can be very misleading since the amount of work different computer chips can do in one cycle varies. Clock rates should not be used when comparing different computers or different processor families. Rather, some kind of software benchmarks should be used.
Smartphones are equipped with more advanced embedded chipsets that can do many different tasks depending on their programming.
The performance of the CPU that's at the core of the chipset is vital for the daily user experience and the general computing performance of the smartphone. People tend to use the clock rate of the main CPU to compare the performance of competing end products. But as we already pointed out, the clock rate of a processor is only useful for providing performance comparisons between computer chips in the same processor family and generation. For all other purposes, it's best to use software benchmarks for determining comparative performance.
3GP video
3GP is a simplified version of the MPEG-4 Part 14 (MP4) container format, designed to decrease storage and bandwidth requirements in order to accommodate mobile phones. It stores video streams as MPEG-4 Part 2 or H.263 or MPEG-4 Part 10 (AVC/H.264), and audio streams as AMR-NB, AMR-WB, AMR-WB+, AAC-LC or HE-AAC.
3GP is designed for effieciency to make it suitable for Streaming across mobile phone networks and storing on mobile devices with very littel storage capacity. Video rarely exceeds a QVGA resolution of 320 x 240 pixels but there are VGA or even D1 resolution exceptions. Audio is usually encoded as either MP3 or AAC-LC (Low Complexity). Framerates for most mobile devices are Limited to 15fps.
There are two different standards for this format:
  • 3GPP (for GSM-based Phones, may have filename extension .3gp)
  • 3GPP2 (for CDMA-based Phones, may have filename extension .3g2)
Both are based on MPEG-4 and H.263 video, and AAC or AMR audio.
When transferred to a computer, 3GP movies can be viewed on Linux, Mac, and Windows platforms with MPlayer and VLC media player. Programs such as Media Player Classic, Totem, RealPlayer, QuickTime, and GOM Player can also be used. Some cell phones use the .mp4 extension for 3GP video.

Accelerometer

The accelerometer is a built-in electronic component that measures tilt and motion. It is also capable of detecting rotation and motion gestures such as swinging or shaking.
The most common use for it is to activate auto screen rotation on mobile devices when the user changes their orientation from portrait to landscape or vice-versa.
Another modern application for the accelerometer is to control the mobile device music player with gestures (Sony Ericsson Shake control or Samsung Motion play technologies).
Accelerometers are also utilized for enriching the gaming controls (navigating by tilting the device instead of by pressing keys).
Another popular mobile phone feature based on an accelerometer is turn-to-mute. It allows user to mute an incoming call, silence an alarm or pause the mobile music player simply by turning the device face down.

Analog

A method of transmitting information using energy waves. It doesn't have discrete levels but is a continuously variable wave. Human voice for example is transferred by directly converting the sound wave to electricity.
Analog cell phones (known also as 1G) used this technology. However virtually all modern cell phones use digital signals (2G or later).

2G

The name usually given to original GSM, CDMA, and TDMA networks. It uses the spectrum more efficiently than analog (1G) systems, and offers digital encryption of conversations. 2G networks introduced data services for mobiles starting with SMS.

3G

Analog cellular phones were the first generation while digital marked the second generation.
3G is loosely defined, but generally includes high data speeds, always-on data access, and greater voice capacity.
The high data speeds are possibly the most prominent feature, and certainly the most hyped. They enable such advanced features as live, streaming video.
There are several different 3G technology standards. The most prevalent is UMTS, which is based on WCDMA (the terms WCDMA and UMTS are often used interchangeably).

CDMA (Code-Division Multiple Access)

CDMA is a digital technology for transmitting data. It is a general technology utilized through various standards.
CDMA has no limit on capacity but the base station will only connect users upon determining that the call quality would fall bellow a predetermined limit.
The term is often used to refer to one specific family of technologies - IS-95 (often referred to cdmaOne) and CDMA2000. Networks using this technology operate in the 800 and 1900 MHz frequency bands and are primarily used in the Americas and Asia.

VoIP (Voice over Internet Protocol)

Voice over Internet Protocol is a technology which allows the transmission of voice over data networks. This makes normal phone calls over such networks possible.

Dual-SIM

This specifies whether a device is capable of supporting two SIM cards. The two major types of dual-SIM phones are active and standby. Dual-SIM Standby (DSS) requires the user to specify which of the two SIMs is able to make and receive calls, while Dual-SIM Active (DSA) enables both cards to receive calls at the same time. This latter feature usually requires an additional transceiver for the secondary SIM card, and as such consumes more battery life. More recent models feature Dual SIM Dual Standby (DSDS) technology which enables them to have two active SIMs with only one transceiver.

Dual-Mode

A dual-mode phone is a phone capable of sending/receiving data in two different ways. For example, a dual-mode phone could support both GSM and CDMA.

Dual-band

Mobile phone networks work using signals on specific frequency bands and a phone must support those bands in order to work with the network. Dual-band refers to the phones ability to work with two different bands. It is important to specify which bands exactly.
Networks in different geographical locations work on different bands - GSM networks in the Americas use the 850 MHz and 1900 MHz bands while networks in Europe, Brazil, Asia and Africa use the 900/1800 MHz bands.
For example an 900/1800 dual-band phone won't work in the US and an 850/1900 phone won't work in Europe. A 900/1900 phone should work on at least one network in most countries around the world.

IP (Internet Protocol)

IP is the the protocol used for communicating data across a packet-switched network used in most publicly accessible networks today. Connections that mobile devices make to GPRS, 3G and similar networks are made using IP.

 

UMTS

UMTS or the Universal Mobile Telecommunications System is a third generation wireless network technology which allows speeds of up to 2Mbps.
UMTS is based on the WCDMA technology, which is why these terms have become interchangeable.

WCDMA(Wideband Code Division Multiple Access)

Wideband CDMA is a third-generation (3G) wireless standard which allows use of both voice and data and offers data speeds of up to 384 Kbps.
The frequency bands for WCDMA are as follows: Europe and Asia - 2100MHz, North America - 1900MHz and 850MHz.
WCDMA is also called UMTS and the two terms have become interchangeable.
Some parts of the WCDMA are based on GSM technology and the networks are designed to integrate the GSM networks at some levels.

HSDPA (High-Speed Downlink Packet Access)

An upgrade for UMTS networks that doubles network capacity and increases download data speeds by five times or more.
The service was initially deployed at 1.8 Mbps but upgrades to the networks and new user devices led to increased rates of 3.6 Mbps, followed by 7.2 Mbps.
HSDPA only handles the downlink while the uplink is handled by a related technology called HSUPA. The combination of both technologies is usually called HSPA.

HSUPA (High-Speed Uplink Packet Access)

An upgrade for UMTS/HSDPA networks that increases upload data speeds up to 5.76 Mbps. HSUPA together with HSDPA are sometimes referred to as HSPA.
The standard is backwards compatible with UMTS and HSDPA and will work with devices supporting only those standards.
HSUPA only handles the uplink while the downlink is handled by a related technology called HSDPA.
CDMA2000
A 3G wireless technology, evolved from cdmaOne. Improvements over the old standard include faster data rates, always-on data service, and improved voice network capacity.
There are three types of CMDA2000:
  • 1xRTT doubles the capacity of cdmaOne and supports up to 144 kbps data speeds
  • 1xEV-DO supports data rates up to 2.4 Mbps but needs to be deployed in a separate spectrum. This standard doesn't support voice calls and needs to be combined with 1xRTT.
  • 1xEV-DV supports data rates of around 3-5 Mbps and voice capabilities

EDGE (Enhanced Data for Global Evolution)

EDGE (also known as Enhanced GPRS or EGPRS) is a data system used on top of GSM networks. It provides nearly three times faster speeds than the outdated GPRS system. The theoretical maximum speed is 473 kbps for 8 timeslots but it is typically limited to 135 kbps in order to conserve spectrum resources. Both phone and network must support EDGE, otherwise the phone will revert automatically to GPRS.
EDGE meets the requirements for a 3G network but is usually classified as 2.75G.
Related terms:

EV-DO

A 3G technology add-on for CDMA networks that allows for theoretical download speeds as fast as 2.4 Mbps, though actual rates tend to be far slower.
There are two major versions: Release 0 and Revision A.
Release 0, the original release, is widely deployed. It offers data rates of 2.4 Mbps, with real-life speeds averaging 300-600 Kbps.
Revision A introduces enhancements that allow features such as VoIP and video calling. Although EV-DO does not support voice calls natively a future upgrade may enable VoIP.

CDMA (Code-Division Multiple Access)

CDMA is a digital technology for transmitting data. It is a general technology utilized through various standards.
CDMA has no limit on capacity but the base station will only connect users upon determining that the call quality would fall bellow a predetermined limit.
The term is often used to refer to one specific family of technologies - IS-95 (often referred to cdmaOne) and CDMA2000. Networks using this technology operate in the 800 and 1900 MHz frequency bands and are primarily used in the Americas and Asia.

GPS (Global Positioning System)

Global Positioning System was developed by the United States' Department of Defense. It uses between 24 and 32 Medium Earth Orbit satellites that transmit precise microwave signals. This enables GPS receivers to determine their current location, time and velocity. The GPS satellites are maintained by the United States Air Force.
GPS is often used by civilians as a navigation system. On the ground, any GPS receiver contains a computer that "triangulates" its own position by getting bearings from at least three satellites. The result is provided in the form of a geographic position - longitude and latitude - to, for most receivers, within an accuracy of 10 to 100 meters. Software applications can then use those coordinates to provide driving or walking instructions.
Getting a lock on by the GPS receivers on the ground usually takes some time especially where the receiver is in a moving vehicle or in dense urban areas. The initial time needed for a GPS lock is usually dependent on how the GPS receiver starts. There are three types of start - hot, warm and cold.
The hot start is when the GPS device remembers its last calculated position and the satellites in view, the almanac used (information about all the satellites in the constellation), the UTC Time and makes an attempt to lock onto the same satellites and calculate a new position based upon the previous information. This is the quickest GPS lock but it only works if you are generally in the same location as you were when the GPS was last turned off.
The warm start is when the GPS device remembers its last calculated position, almanac used, and UTC Time, but not which satellites were in view. It then performs a reset and attempts to obtain the satellite signals and calculates a new position.
The receiver has a general idea of which satellites to look for because it knows its last position and the almanac data helps identify which satellites are visible in the sky. This takes longer than a hot start but not as long as a cold start.
And finally – the cold start is when the GPS device dumps all the information, attempts to locate satellites and then calculates a GPS lock. This takes the longest because there is no known information.
The GPS receiver has to attempt to lock onto a satellite signal from any available satellites, basically like polling, which takes a lot longer than knowing which satellites to look for. This GPS lock takes the longest.
In an attempt to improve lock times, cellphone manufacturers and operators have introduced the Assisted GPS technology, which downloads the current ephemeris for a few days ahead via the wireless networks and helps triangulate the general user’s position with the cell towers thus allowing the GPS receiver to get a faster lock at the expense of several (kilo)bytes.

IMEI (International Mobile Equipment Identity)

IMEI is a unique 15-digit serial number that uniquely identifies a GSM or UMTS mobile phone. It consists of four parts and provides information, such as the manufacturer, to the mobile network. It is usually printed on the device under the battery.
IMEI can be used to "ban" a stolen phone, making it hard to use by the thief with a new SIM card.

Java

Often stands for "Java ME" (the new name of J2ME, Java 2 Platform, Micro Edition). Java ME is a platform for applications running on mobile phones. These, mainly small, applications (e.g. games) can be downloaded from the Internet directly to the phone using its built-in web-browser.

Android

Android is a Linux-based smartphone operating system and software platform created by Google.
The Android platform is supported by the Open Handset Alliance and is open source. Any manufacturer can use Android on their phones and software written for the platform will run on Android-based devices regardless of manufacturer.
Android competes with Windows Mobile, S60, and other smartphone platforms.

Symbian

Symbian OS is an operating system designed for mobile devices.
The Symbian OS is used as the underlying base for two major smartphone platforms: S60 and UIQ. Generally, applications written for one of these platforms are not compatible with the other but as they use the same underlying OS it is easier for developers to convert applications from one of them to the other. The Symbian OS introduced major changes to version 9 that made all previous software incompatible without updating. The platforms based on Symbian subsequent to version 9 are the UIQ 3.0 and later, as well as S60 3rd edition.

Windows Mobile

Windows Mobile is one of the major smartphone platforms and until recently the only touch-enabled smartphone platform.
Windows Mobile actually has two distinct editions - Windows Mobile Standard and Windows Mobile Professional.
Software written for either of the editions is not compatible with the other.
The main difference between the editions is that Windows Mobile Professional supports touchscreen and handwriting recognition.
Windows Mobile is a product created by Microsoft but as the company does not produce any phones itself, it licenses the platform to hardware manufacturers.
Before version 6 was released the Windows Mobile Standard edition was known as Windows Mobile for Smartphone, while the Professional edition was referred to as Windows Mobile for PocketPC.

S60 user interface

S60 (formerly known as Series 60) is one of the major smartphone user interfaces. It is developed mainly by Nokia and uses the Symbian OS as its base. Besides using it in all of its own smartphones, Nokia also licenses S60 to other manufacturers such as Samsung and LG.
S60 is capable of running native third-party S60 applications as well as regular Java applications.
There are several releases of the S60 UI and chronologically they include Series 60 (2001), Series 60 Second Edition (2004), Series 60 3rd Edition (2005) and S60 5th edition (2008).
Thrid-party software written for S60 1st Edition (S60v1) or 2nd Edition (S60v2) is not compatible with S60 3rd Edition (S60v3) and later because it uses a new version of the Symbian OS (v9.1).
The latest S60 5th edition was announced in October 2008. Nokia decided to move directly from the 3rd Edition to the 5th Edition "as a polite gesture to Asian customers" since the number four is considered bad luck in some Asian cultures.
The major feature of S60 5th Edition is support for high-resolution 640x360 touchscreens. Before the 5th Edition, all S60 devices had a button-based user interface.
S60 5th edition has some support for third-party software developed for S60 3rd edition but, it's currently limited and somewhat hit-and-miss.

Antenna

The physical device used for sending/receiving radio waves. Older phones used external antennas while most current phones use an internal antenna. The size and shape of the antenna is designed according

APN (Access Point Name)

APN is the name (web address) of an access point for GPRS/EDGE/UMTS data connection. Usually wireless carriers provide the APN to their end users.
o the type of radio waves being used.

LCD (Liquid Crystal Display)

A liquid crystal display is the most common display type among mobile phones because of its low power consumption and good image quality. They are generally easy to read, even under direct sunlight.
The smallest element of an image displayed on a LCD is the pixel. Each pixel normally consists of a layer of molecules aligned between two transparent electrodes, and two polarizing filters.
Some of the types of LCD displays are STN, TFT and TFD. The first one, STN, offers low cost and low power consumption, but low image quality. TFT features greater image quality and response time, yet its displays are more expensive and need more power.
Three other types of LCDs are transmissive, reflective, or transflective. Transmissive displays offer nicer image quality in low or medium ambient light, while reflective ones work best in bright ambient light. Transflective displays combine the best of both.

Key Lock Switch

A dedicated switch/key/button that locks (and unlocks) a device's keypad.

Key Guard

A feature allowing you to lock the keyboard to avoid any accidental dialing of a number or pressing of keys while carrying the phone in a pocket or bag. The keyboard is unlocked by a special sequence of keys unlikely to be pressed accidentally.

Loudspeaker

The loudspeaker is a small sound driver fitted within a mobile phone, or other communication device, which is used to produce sound. Traditionally, loudspeakers on mobile phones are used to produce sound alerts for events such as incoming calls, incoming messages and alarms.
Since mobile phones have started doubling as portable music players in recent years, users have begun using their built-in speakers for playback of music. Acknowledging this new type of use of the mobile phone loudspeaker, manufacturers have begin to equip their music or video-centric mobiles with more powerful loudspeakers or even a pair of loudspeakers for accurate stereo reproduction and enhanced spatial effects.
Loudspeakers are also used to reproduce voice calls out loud, thus allowing users to deal with calls hands-free or even have conference calls with others in the same room (that use of the mobile phone is called a speakerphone, which is not to be confused with a loudspeaker).
Loudspeaker implementation can vary from model to model. For example, in order to save space and make phones thinner, some manufacturers don't use a dedicated loudspeaker but instead use the earpiece speaker to produce sound alerts as well.
One way or another, whether you use it for fun, conference calls or just for plain ringing, there is one single thing that's important - loudness. We had explored this in depth in our reviews besides the casual subjective remark, but in 2007 we decided it was time we took a more scientific approach.
So we got ourselves a handy piece of equipment - a digital noise/loudness meter - in order to start measuring objectively that all-important aspect of modern handsets - how loud is the loudspeaker in reality.
So, for the record, here is how our test setup goes. We do our tests in one and the same quiet room taking sound measurements with the handset loudspeaker facing the microphone at a distance of exactly 1 m.
We do three different tests. For each test we make several consecutive measurements - we usually disregard the highest and the lowest readings and we take the average value of the rest.
The three tests are as follows:
1) A phone ringing. We use an old-school ringtone, resembling the ringing of an old phone. It seems that most phones do well when we use it.
2) Pink noise. We use a sample of pink noise. Our readings with it are pretty indicative on how well the handset loudspeaker would fare with standard music. Teenagers definitely appreciate a handset that will allow them to crank up the volume as high as possible.
3) Human voice, male. This is an important test, since if you tend the use the loudspeaker for speakerphone purposes, loudness is really important, regardless of whether you are in a conference room or in your car.
You can find the results of all the phones tested posted right here.

Bandwidth

Bandwidth is used to measure the data throughput of a channel or connection. It's the amount of data that can be sent over a connection in a given amount of time without distortion. It should not be confused with band.

Micro USB

A type of USB connector. USB stands for "Universal Serial Bus". Devices connected to the computer using a USB cable can easily exchange files and information (if the device supports Mass Storage mode, the files can be transferred without the need for special drivers or software).
Some devices can be charged via the USB cable when connected to the computer. There are different USB interfaces: MicroUSB (with two subtypes - Micro-A and Micro-B) is one of them, and was developed to replace the older MiniUSB interface. However, the latter is still the most popular connector type in portable devices.

MP3 (MPEG Layer 3)

An audio storage protocol that stores music in a compressed format with very little loss in sound quality.
MP3 is the most common MPEG format for audio files. MP3 files can be played using the music player of the mobile phone or set as a ringtone.

Mobile WiMAX

Mobile WiMAX (WiMAX comes from "Worldwide Interoperability for Microwave Access") is a technical wireless standard allowing web browsing and wireless data transfer on the move. It's an another way of calling the 802.16e protocol.
WiMAX technology provides the equivalent of broadband speeds without the need for cables, and service coverage can extend over an entire city, region or even a whole country.
Access to the WiMAX wireless service is subject to a monthly subscription and it requires the use of a dedicated WiMAX modem, which is usually supplied for free by the operator.
WiMAX technology allows for data transfer speeds of up to 75Mbps, but in reality they tend to be a lot lower than that, at around 1-10 Mbps tops.

Network coverage

The geographical area covered by the network of a service provider. Within this area, the phone will be able to complete a call using the carrier's network or a partner network.

RAM (Random-Access Memory)

This is the memory where the software resides while it is running along with the data it is using. RAM is used by both OS and application software.
RAM is very fast but volatile, meaning that all information is lost when electric power is cut off. That makes it useful for temporary storage of data that requires fast access.
Normally, devices with RAM also have another type of storage memory (flash memory or a hard drive) that stores the information while the power is off.
Devices with more RAM can run more complex software and multiple applications at the same time.

Roaming

Refers to using a mobile phone outside of your service provider's coverage area. Typically, service providers charge higher fees for calls, messages and access to the Internet.

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