In the net (வலை வீசுவோம்) -1 (english)

Dear friends,

In our recent life style, we are looking lot of new arrivals in the market everyday.
Some times it is difficult to understand the technology behind it for our application.

Here one of the site http://www.howstuffworks.com/ helping us to know each and

evrything under the earth .

For example, if you are eager to know about LCD and PLASMA

T.V s and their apllication in the recent market, pls go through the below points,

At the end you can become a master to review flat panel t.vs in all matters.

Flat-Panel TV & HDTV Buying GuideLast Updated: 10/17/2007--->
Flat-Panel TV & HDTV Buying Guide
Buying Guide Glossary Compare Prices Last Updated: 10/17/2007

The Basics:

Flat-Panel TVs & HDTVs
With their ultra-thin cabinets, exceptional versatility, and mind-blowing performance, big-screen plasma and LCD digital televisions offer the ultimate viewing experience. These widescreen flat-panel televisions are thin and light enough to mount on the wall, something a big-screen CRT or other projection television could only dream about. The picture of plasma and LCD screens offers exceptional resolution and detail, and these sets are usually packed with additional features to further enhance the image quality.

Almost all plasma and LCD televisions over 32 inches are HD-ready--that is, they can support high-definition programming supplied by an external HD receiver. Many have integrated HD tuners, so there is no need to add an HD set-top box to enjoy the benefits of high-definition content.

Flat-panel televisions are not just making waves in the big-screen department, as these technologically advanced monitors are also readily available in smaller sizes. As plasma monitors generally aren't made in sizes below 32 inches, virtually all flat-panel displays in this range are LCD models.

In addition to the excellent picture and functionality, these smaller flat-panel televisions can be wall-mounted and will fit into spaces traditional CRT sets cannot hope to go. Many of the larger models are HD-ready, and some even include integrated HD tuners to display high-definition content without the need for an external HD receiver. At the same time, these televisions can often pull double duty as computer monitors, which is no surprise, as LCD is the current technology of choice for viewing computer content.

So which format is better, plasma or LCD? This is a loaded question. A decision between the two often comes down to user preferences, and the differences between plasma and LCD are decreasing every year. Plasma televisions go up to screen sizes of 70 inches or more while LCD sets currently top out at around 45 to 50 inches, although as the technology matures, larger LCD televisions will appear on the marketplace. Plasmas are generally considered to have better image quality and black levels, although comparable-size LCD monitors usually have a higher resolution than their plasma counterparts. Unlike LCD, plasma monitors can suffer from burn-in due to a stationary image on the screen, such as a video game status bar or a news-channel ticker, but the risk can be lessened by a number of internal burn-in prevention functions. Plasma televisions often carry a lower price than comparable-size LCD monitors, but the cost of LCD is dropping faster than that of plasma.

It should be noted that while some sets may be called HDTV or HD-ready, they might not be able to fully display 720p or 1,080i signals, the two current broadcast HD standards. For example, an LCD television with a native resolution of 1,280X720 can handle 720p content with no conversion, but a 1,080i signal must be scaled down to fit on the screen. In addition, some sets (especially plasmas) are not technically HDTVs, but instead are EDTVs (enhanced definition TV) capable of a maximum on-screen display of 480p. True HD signals must be adapted, which costs some resolution, but the picture is still significantly better than anything that can be achieved on a standard analog set.

Both plasma and LCD monitors were prohibitively expensive to most shoppers just a few years ago, but prices have been falling quickly. With advances in technology and additional refinements in the manufacturing process, these high-end televisions are rapidly approaching the price range of a majority of consumers.

How to Shop

The universal rule when shopping for televisions is to buy as large a screen as you can afford, but the plethora of features available with large flat-panel televisions can make the price of similar-size sets vary by hundreds or even thousands of dollars. The best strategy is to determine the features you need, select an approximate dollar amount you want to spend, and research available sets.

When purchasing a plasma or LCD television (or any television, for that matter), it is essential that you try out candidate sets at an electronics store or other location. Demonstration units usually have the contrast set at maximum levels, so make sure to adjust the picture settings accordingly. It is a good idea to bring along a favorite DVD to play, as watching something you're familiar with will give you a better handle on the television's image quality.

If watching high-definition programming is high on your list, a plasma or LCD television with an integrated HD tuner is the way to go. Keep in mind that you may need to upgrade your cable or satellite service to receive HD content, or you will need to install an over-the-air HD antenna. If you are not ready for HD yet, an HD-ready set will allow you to upgrade in the future.

Important features to consider are connections such as DVI (digital visual interface) and HDMI (high-definition multimedia interface), which provide an uncompressed digital-to-digital link between a digital television and a progressive scan DVD player or external HD receiver. With a CableCARD slot and the corresponding card (supplied by the cable provider), a television can display certain cable content without the need for a cable set-top box.

Glossary

16:9 Aspect Ratio TV
These sets are designed to provide widescreen pictures without the letterbox effect (black bars found on the top and bottom of the screen). This is great for wide-format movies, but for conventional pictures you will either end up with a cropped picture on the top or bottom, or black bars on both sides of the picture, or picture-outside-picture on one side. Some projection sets will stretch a standard 4:3 picture to fit the screen, although this usually results in some picture distortion.

Audio and Video Inputs/Outputs

Normally there are more audio outputs than video ones. More audio and video outputs are desirable, as they allow you more versatility in signal switching of multiple VCRs, DVD players, and the like. Depending on how you decide to hook up your A/V system, either the TV or your A/V receiver can be used for video switching. Audio and video input jacks are more desirable for hooking up a VCR than putting the signal through your RF antenna connector, as they will provide you with better audio and video quality.

Cable Terminology

A common cause of confusion for shoppers is the term cable-ready. Many people incorrectly believe that a cable-ready set will allow them to receive pay services free of charge. A cable-ready set only eliminates the need for a converter box to receive basic cable programming. Except for a few 13-inch and smaller sets, every TV sold today is cable-ready. To receive premium channels, which are scrambled, you might need the converter box. To this end, many higher-end sets offer dual antenna inputs. Through the use of a signal splitter (available from your cable company or Radio Shack), you split the signal before it goes into the cable box. One signal goes directly to your TV, and the other to your cable box. The second signal then goes out from your cable box and into the second antenna input of your TV. In this way, all unscrambled programming is available on antenna A, and scrambled/premium services are available on antenna B. As long as your TV has a universal remote, it will control your cable box. Therefore, you do not need your cable company's remote (which is normally provided at an additional cost). Several years ago, a standard interconnect was agreed upon and the TV manufacturers built this interconnect into their sets. IEEE-1394 "Firewire" is a specialized digital computer cable that allows information to be passed in either direction. It is currently used in the computer industry to pass and capture digital video images from digital still cameras to your computer. Firewire lets you connect your digital TV with a myriad of digital accessories, and is instrumental in the development of new services, including digital video programming.

Comb Filter

A feature that improves resolution, picture quality, and reduces objectionable color patterns. Low- to mid-line sets use a glass comb filter. High-end sets use a CCD or digital comb filter, which greatly enhances resolution.

Component Video (Inputs/Outputs)

Also called Color Difference or ColorStream, this is the latest (and best) input/output to date. While similar to RGB (red/green/blue) connections, it separates the luminance and chrominance even further providing superior images over S-VHS. Most step-up DVD players now include component video outputs, which will also be included on most HDTV set-top boxes. Many TV manufacturers are now including these inputs on their mid- to upper-line TVs.

Dual-Antenna Inputs

This feature means your set can accommodate two antenna sources, such as a master antenna and cable box or master antenna/cable box and DSS decoder. By having dual inputs, it allows you to switch easily between antenna sources.

DVI and HDMI interfaces

There are two all-digital video connections for HDTV set-top boxes, monitors, DVD players, and some audio/video receivers: DVI (digital visual interface) and HDMI (high-definition multimedia interface). DVI sends digital video data from a source (such as an HDTV set-top receiver or progressive-scan DVD player) to a display (such as an HD-ready television), and it eliminates the need for digital-to-analog decoders. HDMI builds on DVI by adding multichannel digital audio to the digital video, so digital audio and video can be transmitted in one cable. Both DVI and HDMI incorporate HDCP (high-bandwidth digital content protection), a data encryption method that prevents video piracy. DVI and HDMI both support uncompressed data transfer, and neither is constrained by cable length limitations (up to 500 meters). HDMI is fully backward-compatible with DVI, and with its incorporation of multichannel audio, HDMI is expected to completely replace DVI in the near future.

External Speaker Jacks

These devices allow you to attach separate speakers directly to a TV for improved sound quality, or to attach rear speakers, allowing you to experience surround. The downside to this equation is based on the wattage of your internal television amplifier.

Front A/V Jacks

These jack packs found on the front of a TV (usually hidden under a panel) are a handy feature, especially for hooking up a camcorder or a video game console.

HDTV/HD-Ready

HDTV refers to a television with an integrated high-definition tuner, allowing it to display ATSC (high-definition) broadcasts. An HD-ready set has the ability to display HD content, but it requires an external HD receiver or set-top box. EDTV (enhanced-definition TV) describes a television that can display HD content but at lower resolutions than true HDTV. Nevertheless, EDTV displays are still far superior to standard analog displays.

Horizontal Resolution

Horizontal resolution is the number of horizontal lines that the television can display. Theoretically, the more lines that can be displayed, the better the picture. Broadcast television displays 330 lines, VHS tapes about 240 lines, S-VHS tapes about 400 from a pre-recorded video (330 from broadcast), and DVD about 425 lines. When broadcast, satellite, DSS, and video sources become available with greater resolution, sets with higher horizontal resolution will be able to receive an enhanced signal.

Invar Shadow Mask

Invar shadow mask gives the picture more brightness and punch. Invar is considered to be a premium feature. When sets are very bright, a side effect called "blooming" occurs. To counteract this bleeding of colors, some manufacturers include the invar shadow mask.

Notch Filter

This filter helps remove a small part of the signal that contains excess color information. By doing so, it helps eliminate some objectionable color effects. However, using this circuit creates a slight loss in picture resolution.

Number of Speakers

Indicates the number of speakers found on a particular television set. Obviously, for people who do not plan to attach additional speakers, more is better.

Parental Lock-Out or Channel Block

All sets larger than 13 inches now include a V-chip (V for violence) that allows parents to lock out certain programs if they have too much violence or sexual content. By punching in a special code (that you as the parent devise), parents can lock out children (or anyone else) from viewing specific channels or disable the TV from being used during a specified time of day.

Picture-in-Picture (PIP)

PIP lets you view two image sources simultaneously. The primary picture displays full-size on the screen, while the second picture is normally placed in a smaller box located in one corner of the screen. To use PIP, you need a second video source such as a VCR. A handful of upper-end sets include a second tuner for PIP, thereby eliminating the need to use the VCR tuner as the second video source. Advanced PIP lets you display multiple PIXs (or channels) on the screen at the same time (all are frozen except the channel that it is presently scrolling through), change the size or location the smaller box, and swap back and forth between main and PIP. Picture-outside-picture (POP; also known as picture-out-of-picture) allows the screen to be split into two equal-sized, side-by-side pictures. POP is sometimes considered a function of PIP, and many manufacturers do not distinguish between the two.

Premium Sound Systems

Manufacturers are looking for ways to come up with better sound enhancement systems. RCA and Sony, for example, include SRS (Sound Retrieval System), developed by Hughes for use in their high-end sets. SRS adds depth and more realistic sound without adding additional speakers. Similar systems have been developed by Toshiba with their Cyclone Sub-Bass System with 4-channel DSP, and Zenith with SEQ. Some manufacturers are now adding Spatializer sound to enhance their audio.

Remote

Sets have either a basic, standard, unified, universal, or learning remote. There are also a few combination universal/learning models. A basic remote controls basic functions, such as volume or channel up/down and power on and off. A standard remote is an enhanced basic model with a keypad for direct access and access to on-screen menus and displays. Universal remotes are becoming the most common remotes. They come with pre-programmed codes for both VCRs and cable boxes. Some brands offer models that are ergonomically designed with keys of different shapes, colors, and sizes. On top of that, a handful of brands include devices with illuminated keys. That's a feature you'll appreciate when trying to read those buttons in a semi-dark room. Learning remotes can be taught codes from other types of components, such as A/V receivers and surround processors. If you are trying to tie all of your components together, a learning remote might be the best option. However, at best, they can learn only primary functions for each component. Normally, you cannot get into menus from other products to adjust surround settings, for example. A learning remote from an A/V receiver or an aftermarket universal/learning unit might be a better bet for trying to tie all of your components together.

S-Video (Inputs/Outputs)

Many components besides S-VHS VCRs now include S-video jacks. S-video separates the luminance (Y) and chrominance (C) signals, offering better picture quality than standard video inputs. S-video jacks increase resolution, help color reproduction, and help reduce jitter at scene transitions. To get the most out of your video source, you must use an S-video jack for the highest resolution.

Scan Velocity Modulation

Scan velocity modulation adjusts the rate of horizontal movement of the beam as it "draws" the scan lines, which gives black-and-white picture transitions more punch. This results in a sharper picture.

Special Picture Tubes

A better grade of picture tube is normally found in larger sets. A recent innovation that has taken the industry by storm is the inclusion of either dark-tint or dark-glass picture tubes. By offering darker faceplates, these picture tubes provide greater contrast between black and white. Those brands that include darkened picture tubes have had to increase brightness levels so that the picture does not appear too dark. Most consumers prefer brightness to color accuracy. Other advancements include flattened picture tubes, which offer less distortion on the outer edges of the picture. Some manufacturers use a combination of techniques to tweak out the highest performance from their picture tubes. These sets, while costly, offer the viewer a picture with the highest resolution and provide the most lifelike appearance.

Stereo (Watts Per Channel)

Many sets include a multichannel television sound decoder (MTS), which receives and decodes all stereo signals broadcast by the networks or cable channels. Watts per channel refers to the wattage of the set's stereo amplifier. Some manufacturers' literature can be a bit deceptive if it indicates that the TV has a 20-watt amplifier. This normally means that the set can produce 10 watts per channel.

Surround

Many manufacturers include matrix surround sound or other psycho-acoustic effects to enhance the audio. It might also be called ambiance or extended stereo effects. However, more and more sets are now including Dolby Pro Logic as a means to greatly enhance the audio quality. Obviously, you must add rear speakers to obtain the desired effect. A major drawback with these sets is their underpowered amps. Even with 5 or 10 watts per channel, these amps just don't cut it. Many sets include variable audio outs for connection to an A/V receiver, but few sets offer ample wattage. Some sets also include a center-channel input, which allows you to use the TV's internal speakers for the center channel. Other manufacturers, such as Sony, Toshiba, and RCA, offer special speaker systems that are compatible with their sets for an additional cost

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