Functions and Type of Computer Cards

8/2/2019 Functions and Type of Computer Cards

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Function and types of

Computer cardsComputer cards are devices which are used to connect peripheral components.They are a printed circuit board used to accomplish a specific task.

These types of cards can be connected to a computer in two ways:

Using the PCI slots on a motherboard

This is a typical interface used mostly. If the on-

board card fails to work, it is possible to plug anew card on the PCI slot and continue your work.

This is one of the advantages of having PCI slotson a motherboard.

Built-in on a motherboard

Current computer already have all the main cardsintegrated with the main board, no need to buy additional cards. Unless for

better performance specially if you are in video gaming and graphical

applications.

Several kinds of cards can be fitted on a computer. Modern computerincorporates at leastgraphics, sound and network cards on the main board means they are built with the motherboard.

Internal modem and TV cards are the other types of cards which can be hookedon PCI slot.

Types of PC cards

Graphics card enables to display images and videos on screen

Sound card enables to play music on a computer
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Network card allows computers to communicate each other

Modem card used to connect to a telephone line to get dialup internet service

How Sound Cards Work

Computer Hardware Image Gallery

A sound card allows a computer to create and record real, high-quality sound. See morecomputer hardwarepictures.

Photo courtesyHowStuffWorks Shopper

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Before the invention of the sound card, aPCcould make one sound - a beep. Although the computer

could change the beep's frequency and duration, it couldn't change the volume or create other sounds.

At first, the beep acted primarily as a signal or a warning. Later, developers created music for the earliest

PC games using beeps of different pitches and lengths. This music was not particularly realistic -- you can

hear samples from some of these soundtracks atCrossfire Designs.

Fortunately, computers' sound capabilities increased greatly in the 1980s, when several manufacturers

introduced add-on cards dedicated to controllingsound. Now, a computer with a sound card can do far

more than just beep. It can produce 3-D audio for games or surround sound playback forDVDs. It can

also capture and record sound from external sources.
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In this article, you'll learn how a sound card allows a computer to create and record real, high-quality

sound.4. See more

A sound card must translate between sound waves andbits and bytes.

Analog vs. Digital

Sounds and computer data are fundamentally different. Sounds are analog - they are made of waves that

travel through matter. People hear sounds when these waves physically vibrate theireardrums.

Computers, however, communicate digitally, using electrical impulses that represent 0s and 1s. Like a

graphics card, a sound card translates between a computer's digital information and the outside world's

analog information.

Sound is made of waves that travel through a medium, such as air or water.

The most basic sound card is a printed circuit board that uses four components to translateanalogand digitalinformation:

An analog-to-digital converter (ADC)

A digital-to-analog converter (DAC)

An ISA or PCI interface to connect the card to themotherboard

Input and output connections for a microphone andspeakers

Instead of separate ADCs and DACs, some sound cards use a coder/decoder chip, also called

a CODEC, which performs both functions.

In the next section, we'll explore the analog-to-digital and digital-to-analog conversions that take

place on the sound card.

X-FI

One of the newest advances in sound card technology is , or Xtreme Fidelity, from SoundBlaster

manufacturerCreative. features:

"Active Modal Architecture," which gives people different sound options for games, leisure use or music

creation

A Digital Signal Processor (DSP) with 51 million transistors
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Multiple processing engines, each of which performs specific sound operations

A 24-bit Crystallizer, which reverses some of the sound quality loss inherent in 16-bitCDrecording

4. See more

An analog-to-digital converter measures sound waves at frequent intervals.

ADCs and DACs

Imagine using yourcomputerto record yourself talking. First, you speak into amicrophonethat you have

plugged into your sound card. The ADC translates the analog waves of your voice into digital data that

the computer can understand. To do this, it samples, or digitizes, the sound by taking precise

measurements of the wave at frequent intervals.

The number of measurements per second, called the sampling rate, is measured in kHz. The faster a

card'ssampling rate, the more accurate its reconstructed wave is.

If you were to play your recording back through thespeakers, the DAC would perform the same basic

steps in reverse. With accurate measurements and a fast sampling rate, the restored analog signal can

be nearly identical to the original sound wave.

Even high sampling rates, however, cause some reduction in sound quality. The physical process of

moving sound through wires can also cause distortion. Manufacturers use two measurements to

describe this reduction in sound quality:

Total Harmonic Distortion (THD), expressed as a percentage

Signal to Noise Ratio (SNR), measured in decibels

For both THD and SNR, smaller values indicate better quality. Some cards also support digital input,

allowing people to store digital recordings without converting them to an analog format.

Next, we'll look at the other components commonly found on sound cards and what they do.

METHODS OF SOUND CREATION

Computers and sound cards can use several methods to create sounds. One is frequency

modulation (FM) synthesis, in which the computer overlaps multiple sound waves to make more complex

wave shapes. Another is wave table synthesis, which uses samples of real instruments to replicate

musical sounds. Wave table synthesis often uses several samples of the same instrument played at
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different pitches to provide more realistic sounds. In general, wave table synthesis creates more accurate

reproductions of sound than FM synthesis.

4. See more

A PCI sound card

Other Sound Card Components

In addition to the basic components needed for sound processing, many sound cards include additional

hardware or input/output connections, including:

Digital Signal Processor (DSP): Like a graphics processing unit (GPU), a DSP is a

specializedmicroprocessor. It takes some of the workload off of the computer's CPU by performing

calculations for analog and digital conversion. DSPs can process multiple sounds, or channels,

simultaneously. Sound cards that do not have their own DSP use the CPU for processing. Memory: As

with agraphics card, a sound card can use its ownmemoryto provide faster data processing. Input and

Output Connections: Most sound cards have, at the very minimum, connections for

amicrophoneandspeakers. Some include so many input and output connections that they have

abreakout box, which often mounts in one of the drive bays, to house them. These connections include:

Multiple speaker connections for 3-D andsurround sound

Sony/Philips Digital Interface (S/PDIF), a file transfer protocol for audio data. It uses either coaxial or

optical connections for input to and output from the sound card.

Musical Instrument Digital Interface (MIDI), used to connect synthesizers or other electronic instrumentsto their computers.

FireWireandUSBconnections, which connect digital audio or video recorders to the sound card

Game designers use 3-D sound to provide fast-paced, dynamic sound that changes based on a player's

position in the game. In addition to using sound from different directions, this technology allows realistic

recreations of sound traveling around or through obstacles.Surround soundalso uses sound from
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several directions, but the sound does not change based on the listener's actions. Surround sound is

common inhome theatersystems.

Like agraphics card, a sound card uses software to help it communicate with applications and with the

rest of the computer. This software includes the card's drivers, which allow the card to communicate with

theoperating system. It also includes application program interfaces (APIs), which are sets of rules orstandards that make it easier for software to communicate with the card. The most common APIs include:

Microsoft: DirectSound

Creative: Environmental Audio Extensions (EAX) and Open AL

Sensaura: MacroFX

QSound Labs: QSo

Next, we'll look at integratedmotherboardand external sound control options.

3-D VS SURROUND SOUND AND DRIVERS & APIS

Game designers use 3-D sound to provide fast-paced, dynamic sound that changes based on a player's

position in the game. In addition to using sound from different directions, this technology allows realistic

recreations of sound traveling around or through obstacles.Surround soundalso uses sound from

several directions, but the sound does not change based on the listener's actions. Surround sound is

common inhome theatersystems.

Like agraphics card, a sound card uses software to help it communicate with applications and with the

rest of the computer. This software includes the card's drivers, which allow the card to communicate with

theoperating system. It also includes application program interfaces (APIs), which are sets of rules or

standards that make it easier for software to communicate with the card. The most common APIs include:

Microsoft: DirectSound

Creative: Environmental Audio Extensions (EAX) and Open AL

Sensaura: MacroFX

QSound Labs: QSound

4. See more
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External sound controller

Photo courtesyHowStuffWorks Shopper

Other Options for Sound Control

Not every computer has a sound card. Some motherboards feature integrated audio support instead.

Amotherboardthat has its own DSP can process multiple data streams. It may also support 3-D positional

and Dolbysurround sound. However, in spite of these features, most reviewers agree that separate

sound cards provide better audio quality.

Laptops usually have integrated sound capabilities on their motherboards or small sound cards. However,

space and temperature control considerations make top-of-the-line internal cards impractical.So,laptopusers can purchase external sound controllers, which useUSBorFireWireconnections. These

external modules can significantly improve laptop sound quality.

For more information on sound cards and related topics, check out the links on the following page.

SHOPPING FOR A SOUND CARD

Numerous factors affect a sound card's abilities to provide clear, high-quality sound. When shopping for a

sound card, pay attention to:

ADC and DAC data capacity, measured inbits

Signal-to-noise ratio (SNR) and total harmonic distortion (THD)

Frequency response, or how loudly the card can play sounds at different frequencies

Sampling rate

Output channels, such as 5.1 or 7.1 surround sound

Supported application programming interfaces (APIs)

Certifications, including Dolby Master and THX
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Anyone investing in a top-of-the-line sound card should also have high-qualityspeakers. Even the best

sound card cannot compensate for poor speaker quality.

How Graphics Cards Work4. See all Hardware Basics articles

Computer Hardware Image Gallery

Graphics cards take data from the CPU and turn it into pictures. See more computer hardware pictures.

The images you see on yourmonitorare made of tiny dots called pixels. At most common resolution

settings, a screen displays over a million pixels, and the computer has to decide what to do with every

one in order to create an image. To do this, it needs a translator -- something to takebinary datafrom

theCPUand turn it into a picture you can see. Unless a computer has graphics capability built intothemotherboard, that translation takes place on the graphics card.

A graphics card's job is complex, but its principles and components are easy to understand. In this article,

we will look at the basic parts of a video card and what they do. We'll also examine the factors that work

together to make a fast, efficient graphics card.

Think of a computer as a company with its own art department. When people in the company want a

piece of artwork, they send a request to the art department. The art department decides how to create the

image and then puts it on paper. The end result is that someone's idea becomes an actual, viewable

picture.

A graphics card works along the same principles. TheCPU, working in conjunction with software

applications, sends information about the image to the graphics card. The graphics card decides how to

use the pixels on the screen to create the image. It then sends that information to themonitorthrough a

cable.

Creating an image out ofbinary datais a demanding process. To make a3-Dimage, the graphics card

first creates a wire frame out of straight lines. Then, it rasterizes the image (fills in the remaining pixels).
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It also addslighting, texture and color. For fast-paced games, the computer has to go through this

process about sixty times per second. Without a graphics card to perform the necessary calculations, the

workload would be too much for the computer to handle.

The graphics card accomplishes this task using four main components:

Amotherboardconnection for data and power

Aprocessorto decide what to do with each pixel on the screen

Memoryto hold information about each pixel and to temporarily store completed pictures

Amonitorconnection so you can see the final result

Next, we'll look at the processor and memory in more detail.

4. See all Hardware Basics articles

Graphics cards take data from the CPU and turn it into pictures. Find out the parts of a graphics card and readexpert reviews of graphics cards.

2008 HowStuffWorks

The GPU

Like amotherboard, a graphics card is a printed circuit board that houses aprocessorandRAM. It also

has an input/output system(BIOS)chip, which stores the card's settings and performs diagnostics on

thememory, input and output at startup. A graphics card's processor, called agraphics processing

unit (GPU), is similar to a computer's CPU. A GPU, however, is designed specifically for performing the

complex mathematical and geometric calculations that are necessary for graphics rendering. Some of the

fastest GPUs have more transistors than the average CPU. A GPU produces a lot of heat, so it is usually

located under a heat sink or a fan.

In addition to its processing power, a GPU uses special programming to help it analyze and use

data. ATIand nVidia produce the vast majority of GPUs on the market, and both companies have

developed their own enhancements for GPU performance. To improve image quality, the processors use:

Full scene anti aliasing (FSAA), which smoothes the edges of 3-D objects
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Anisotropic filtering (AF), which makes images look crisper

Each company has also developed specific techniques to help the GPU apply colors, shading, textures

and patterns.

As the GPU creates images, it needs somewhere to hold information and completed pictures. It uses thecard'sRAMfor this purpose, storing data about each pixel, its color and its location on the screen. Part of

the RAM can also act as a frame buffer, meaning that it holds completed images until it is time to display

them. Typically, video RAM operates at very high speeds and is dual ported, meaning that the system

can read from it and write to it at the same time.

The RAM connects directly to the digital-to-analog converter, called the DAC. This converter, also

called the RAMDAC, translates the image into an analog signal that the monitor can use. Some cards

have multiple RAMDACs, which can improve performance and support more than one monitor. You can

learn more about this process inHow Analog and Digital Recording Works.

The RAMDAC sends the final picture to the monitor through a cable. We'll look at this connection andother interfaces in the next section.

THE EVOLUTION OF GRAPHICS CARDS

Graphics cards have come a long way since IBM introduced the first one in 1981. Called aMonochrome

Display Adapter (MDA), the card provided text-only displays of green or white text on a black screen.

Now, the minimum standard for new video cards is Video Graphics Array (VGA), which allows 256

colors. With high-performance standards like Quantum Extended Graphics Array (QXGA), video cards

can display millions of colors at resolutions of up to 2040 x 1536 pixels.


This Radeon X800XL graphics card has DVI, VGA and ViVo connections.

PCI Connection
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Graphics cards connect to the computer through the motherboard. Themotherboardsupplies power to

the card and lets it communicate with theCPU. Newer graphics cards often require more power than the

motherboard can provide, so they also have a direct connection to the computer's power supply.

Connections to the motherboard are usually through one of three interfaces:

Peripheral component interconnect(PCI)

Advanced graphics port(AGP)

PCI Express(PCIe)

PCI Express is the newest of the three and provides the fastest transfer rates between the graphics card

and the motherboard. PCIe also supports the use of two graphics cards in the same computer.

Most graphics cards have two monitor connections. Often, one is a DVI connector, which

supportsLCDscreens, and the other is a VGA connector, which supportsCRTscreens. Some graphics

cards have two DVI connectors instead. But that doesn't rule out using a CRT screen; CRT screens can

connect to DVI ports through an adapter. At one time, Apple made monitors that used the proprietaryApple Display Connector (ADC). Although these monitors are still in use, new Apple monitors use a DVI

connection.

Most people use only one of their two monitor connections. People who need to use two monitors can

purchase a graphics card with dual head capability, which splits the display between the two screens. A

computer with two dual head, PCIe-enabled video cards could theoretically support four monitors.

In addition to connections for the motherboard and monitor, some graphics cards have connections for:

TV display: TV-out or S-video

Analog video cameras: ViVo or video in/video out

Digital cameras:FireWireorUSB

Some cards also incorporate TV tuners. Next, we'll look at how to choose a good graphics card.

DIRECTX AND OPEN GL

DirectX and Open GL are application programming interfaces, or APIs. An API helps hardware and

software communicate more efficiently by providing instructions for complex tasks, like 3-D rendering.

Developers optimize graphics-intensive games for specific APIs. This is why the newest games often

require updated versions of DirectX or Open GL to work correctly.

APIs are different from drivers, which are programs that allow hardware to communicate with a

computer'soperating system. But as with updated APIs, updated device drivers can help programs run

correctly.

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Some cards, like the ATI All-in-Wonder, include connections for televisions and video as well as a TV tuner.

Photo courtesy ofHowStuffWorks Shopper

Choosing a Good Graphics Card

A top-of-the-line graphics card is easy to spot. It has lots ofmemoryand a fastprocessor. Often, it's also

more visually appealing than anything else that's intended to go inside a computer's case. Lots of high-

performance video cards are illustrated or have decorative fans or heat sinks.

But a high-end card provides more power than most people really need. People who use their computers

primarily fore-mail, word processing or Web surfing can find all the necessary graphics support on

amotherboardwith integrated graphics. A mid-range card is sufficient for most casual gamers. People

who need the power of a high-end card include gaming enthusiasts and people who do lots of 3-D

graphic work.

A good overall measurement of a card's performance is its frame rate, measured in frames per second

(FPS). The frame rate describes how many complete images the card can display per second. The

human eye can process about 25 frames every second, but fast-action games require a frame rate of at

least 60 FPS to provide smooth animation and scrolling. Components of the frame rate are:

Triangles or vertices per second:3-Dimages are made of triangles, or polygons. This measurement

describes how quickly the GPU can calculate the whole polygon or the vertices that define it. In general, it

describes how quickly the card builds a wire frame image.

Pixel fill rate: This measurement describes how many pixels the GPU can process in a second, which

translates to how quickly it can rasterize the image.

The graphics card's hardware directly affects its speed. These are the hardware specifications that most

affect the card's speed and the units in which they are measured:

GPU clock speed (MHz)
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Size of the memory bus (bits)

Amount of available memory (MB)

Memory clock rate (MHz)

Memory bandwidth (GB/s)

RAMDAC speed (MHz)

The computer'sCPUandmotherboardalso play a part, since a very fast graphics card can't compensate

for a motherboard's inability to deliver data quickly. Similarly, the card's connection to the motherboard

and the speed at which it can get instructions from the CPU affect its performance.

For more information on graphics cards and related topics, check out the links on the following page.

INTEGRATED GRAPHICS AND OVERLOCKING

Manymotherboardshave integrated graphics capabilities and function without a separate graphics card.

These motherboards handle 2-D images easily, so they are ideal for productivity and Internet

applications. Plugging a separate graphics card into one of these motherboards overrides the onboard

graphics functions.

Some people choose to improve their graphics card's performance by manually setting their clock speed

to a higher rate, known as overclockings. People usually overclock theirmemory, since overclocking the

GPU can lead to overheating. While overclocking can lead to better performance, it also voids the

manufacturer's warranty.
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