Television (often abbreviated to TV or telly) is a widely used telecommunication system for broadcasting and receiving moving pictures and sound over a distance. The term may also be used to refer specifically to a television set, programming or television transmission. The word is derived from mixed Latin and Greek roots, meaning "far sight": Greek tele , far, and Latin vision, sight (from video, vis- to see, or to view in the first person).
A television system may be made up of multiple components, so a screen which lacks an internal tuner to receive the broadcast signals is called a monitor rather than a television. A television may be built to receive different broadcast or video formats, such as high-definition television, commonly referred to as HDTV. HDTV costs more than normal TV but is becoming more available.

HDTV (high definition television) is a television display technology that provides picture quality similar to 35 mm. movies with sound quality similar to that of today's compact disc. Some television stations have begun transmitting HDTV broadcasts to users on a limited number of channels. HDTV generally uses digital rather than analog signal transmission. However, in Japan, the first analog HDTV program was broadcast on June 3, 1989. The first image to appear was the Statue of Liberty and the New York Harbor. It required a 20 Mhz channel, which is why analog HDTV broadcasting is not feasible in most countrie.
HDTV and standard definition television (SDTV) are the two categories of display formats for digital television (DTV) transmissions, which are becoming the standard. HDTV provides a higher quality display with a vertical resolution display from 720p to 1080i. The p stands for progressive scanning, which means that each scan includes every line for a complete picture, and the i stands for interlaced scanning which means that each scan includes alternate lines for half a picture. These rates translate into a frame rate of up to 60 frames per second, twice that of conventional television. One of HDTV's most prominent features is its wider aspect ratio (the width to height ratio of the screen) of 16:9, a development based on research showing that the viewer's experience is enhanced by screens that are wider. HDTV pixel numbers range from one to two million, compared to SDTV's range of 300,000 to one million. New television sets will be either HDTV-capable or SDTV-capable, with receivers that can convert the signal to their native display format.

Answered by Nagendra , an ibibo Master, at 7:57 AM on May 07, 2008

Ordinary Television (often abbreviated to TV or telly) is a widely used telecommunication system for broadcasting and receiving moving pictures and sound over a distance. The term may also be used to refer specifically to a television set, programming or television transmission. The word is derived from mixed Latin and Greek roots, meaning "far sight": Greek tele (τῆλε), far, and Latin vision, sight (from video, vis- to see, or to view in the first person).Commercially available since the late 1930s, the television set has become a common household communications device in homes and institutions, particularly as a source of entertainment and news. Since the 1970s, video recordings on VCR tapes and later, digital playback systems such as DVDs, have enabled the television to be used to view recorded movies and other programs.A television system may be made up of multiple components, so a screen which lacks an internal tuner to receive the broadcast signals is called a monitor rather than a television. A television may be built to receive different broadcast or video formats, such as high-definition television, commonly referred to as HDTV. HDTV costs more than normal TV but is becoming more available.

High-definition television (HDTV) is a digital television broadcasting system with greater resolution than traditional television systems (NTSC, SECAM, PAL). HDTV is digitally broadcast because digital television (DTV) requires less bandwidth if sufficient video compression is used.
The rise in popularity of large screens and projectors has made the limitations of conventional Standard Definition TV (SDTV) increasingly evident. A HDTV compatible television set will not improve the quality of SDTV channels. To display a superior picture, high definition televisions require a High Definition (HD) signal. Typical sources of HD signals are as follows:

* Over the air with an antenna. Most cities in the US with major network affiliates broadcast over the air in HD. To receive this signal a HD tuner is required. Most newer high definition televisions have a HD tuner built in. For HDTV televisions without a built in HD tuner, a separate set-top HD tuner box can be rented from a cable or satellite company or purchased.
* Cable television companies often offer HDTV broadcasts as part of their digital broadcast service. This is usually done with a set-top box or CableCARD issued by the cable company. Alternatively one can usually get the network HDTV channels for free with basic cable by using a QAM tuner built into their HDTV or set-top box. Some cable carriers also offer HDTV on-demand playback of movies and commonly viewed shows.
* Satellite-based TV companies, such as DirecTV and Dish Network (both in North America), Sky Digital (in the UK and Ireland), Bell ExpressVu and Star Choice (both in Canada) and NTV Plus (in Russia), offer HDTV to customers as an upgrade. New satellite receiver boxes and a new satellite dish are often required to receive HD content.
* Video game systems, such as the Xbox, PlayStation 3, and Xbox 360, and digital set-top boxes that rely on an Internet connection, such as the Apple TV, can output a HD signal. The Xbox Live Marketplace, iTunes, and PlayStation Network services offer HD movies, TV shows, movie trailers, and clips for download, but at lower bitrates than Blu-ray.
* Most newer computer graphics cards have either HDMI or DVI interfaces, which can be used to output images or video to a HDTV.
* The optical disc standard Blu-ray Disc (25GB-50GB) can provide enough digital storage to store hours of HD video content.[

Answered by Kaushal , an ibibo Advisor, at 7:29 PM on April 17, 2008

What is HDTV?
High-definition television, or HDTV, is the ultimate home entertainment experience, bringing sound and picture quality to a whole new level. The image quality is 4.5 times greater than that of an ordinary television, creating lifelike images with crisp, high-resolution detail guaranteed to impress its viewers time and time again.

With 5.1 separate channels of surround sound engulfing the room, it brings a total theater experience straight into your home.

HDTV is 100 percent digital, so there's never any chance of image distortion or disruption. And with thousands of hours of high-definition programming available each week and more on the way, there is no end in sight to the possibilities of totally immersive viewing encounters for you and your family.

Are there different types of HDTV sets?
There are. Depending on your individual needs and specific circumstances, including room layout, budget, and priorities, there are several options to choose from. Flat-panel LCD's and plasmas offer the best space-saving solution; however, they tend to be more expensive than other alternatives. Rear-projection systems offer relatively large images at more affordable prices, but they may not fit into certain rooms due to their size. Front projectors offer the biggest HDTV images, but conditions such as room brightness can limit their full potential in certain spaces. Direct-view HDTV sets offer the time-tested reliability of television picture tube technology, but their larger size can make placement in certain rooms tricky. At the end of the day, room size, lighting conditions, and budget will help you to make your choice.

Do I need special equipment to show HD on my TV?
An HD-enabled unit is really the only piece of equipment you'll need. Standard television sets do not have the ability to generate the image quality of HD. In addition to the display, you'll also need a programming source, such as an over-the-air receiver and antenna, cable television HDTV set-top box, or direct broadcast satellite HD antenna and receiver. Those are the main components for receiving HD on your TV. Adding a home theater sound system will allow you to experience the rich audio experience to complement your dynamic picture quality.

What's the difference between Wide-screen, Full, and Zoom?
It's all about how the image is displayed. Ordinary TVs are usually square, while HDTV sets are rectangular in shape. Because of the difference in their aspect ratios (4:3 for ordinary TV and 16:9 for HDTV), various options are available to accommodate an ordinary TV image that is displayed on an HDTV.
One approach, called "window view," keeps the original square format of the typical TV aspect ratio, while placing vertical black bars on either side to fill the wide-screen HDTV. A second approach has the HDTV zoom in on the original TV picture, which fills the screen, but at the same time cuts off portions of the image that fall outside of the zoom range. The third approach stretches the image horizontally to fill the wide-screen HDTV, often resulting in a somewhat unnatural "stretch effect." And finally, a "theatrical," or "panoramic," view can be set to combine the proper aspects of the zoom, resulting in a full view and noticeably reducing any degrees of image distortion at the same time.

What's the difference between 720p and 1080i?
In the United States, there are two transmission standards for HDTV: 720p and 1080i. In a 720p display there are 720 individual horizontal lines, each with 1,280 pixels. Likewise, in a 1080i display there are 1,080 horizontal scan lines in a picture, with 1,920 individual pixels.
The letters "p" and "i" refer to how the lines are presented on-screen. The letter "p" stands for progressive scan, meaning the display writes the lines to screen one after another (line No. 1, line No. 2

Answered by shepherd , an ibibo Master, at 6:19 PM on April 17, 2008

well saurabh HDTV broadcast pictures come in two formats. The first is 720p ("p" stands for progressive), which is an image comprised of 1280 lines along the horizontal by 720 vertical lines. It shows the whole image in a single frame – that is, progressively.

The second is 1080i, which measures 1920 x 1080 lines and is displayed as two fields that are interlaced. You get a bit more detail with 1080i but the interlaced image is not as smooth as a progressively scanned one.

A high-res screen with at least 720 lines will show both formats but only a 1080-line screen will show 1080i footage at its best, i.e. in an un-scaled form.

As far as Sky is concerned it will be down to the programme maker to choose which format to use.

The 1080p format, which is the absolute best form of HD is not used by broadcasters. Movies made in 1080p (e.g. the last three Star Wars films) might appear in Blu-ray and/or HD DVD format. Sony's PlayStation 3 produces 1080p output.

There are more and more 'Full HD' screens (capable of displaying 1080p) appearing. A 1080p screen can de-interlace a 1080i signal or upscale a standard definition one. With very few 1080p sources available, the main benefit of a Full HD screen is its ability to map a source such as Sky TV (1080i) pixel for pixel to the screens resolution (ie 1920 x 1080).

Answered by satyaiitk , an ibibo Master, at 5:11 PM on April 17, 2008

well saurav HDTV is Short for High-Definition Television, a new type of television that provides much better resolution than current televisions based on the NTSC standard. HDTV is a digital TV broadcasting format where the broadcast transmits widescreen pictures with more detail and quality than found in a standard analog television, or other digital television formats. HDTV is a type of Digital Television (DTV) broadcast, and is considered to be the best quality DTV format available. Types of HDTV displays include direct-view, plasma, rear screen, and front screen projection. HDTV requires an HDTV tuner to view and the most detailed HDTV format is 1080i.

* HDTV Minimum Performance Attributes:

* Receiver: Receives ATSC terrestrial digital transmissions and decodes all ATSC Table 3 video formats
* Display Scanning Format: Has active vertical scanning lines of 720 progressive (720p), 1080 interlaced (1080i), or higher
* Aspect Ratio: Capable of displaying a 16:9 image1
* Audio: Receives and reproduces, and/or outputs Dolby Digital audio


whereas TV's create a picture from a gas (plasma) filled with xenon and neon atoms and millions of electrically charged atoms and electrons, that collide when you turn the power on. The energy the collision releases increases the energy level in the plasma and the neon and xenon release photons of light (similar to the way neon lights work). Plasma TVs offer large viewing areas (up to 50 inches) but are very thin. While they offer excellent picture quality, they are quite expensive and are fast becoming the popular choice for HDTV.

Answered by sujata , an ibibo Specialist, at 2:33 PM on April 17, 2008

saurabh Here is where things may start to get confusing for the consumer. All HDTV is digital, but not all Digital TV is HDTV. As stated previously, in the answer to question #1, the same bandwidth for digital TV broadcasting can either used to supply a video signal (or several) and other services, or can be used to transmit a single HDTV signal.
Although there are technically 18 different standards for digital TV broadcasting (all Digital TV tuners are required to decode all 18 standards), the practical application of DTV has come down to 3 standards. These standards are: 480p, 720p, and 1080i.

480p

If you have a progressive scan DVD player and TV, you are familiar with 480p (480 lines of resolution, scanned progressively). 480p is similar to the same resolution of standard broadcast TV (and is referred to as SDTV or Standard Definition Television), but the image is scanned progressively, rather than in alternate fields.

480p does provide an excellent picture (especially on smaller 20-27" screens). It is much more film-like than standard cable or even standard DVD output, but it only provides half the potential video quality of an HDTV picture, therefore its effectiveness is lost on larger screen sets. Although 480p is part of the approved DTV broadcasting scheme, it is not HDTV. This standard was included as one of the DTV broadcasting standards to provide broadcasters the option of providing multiple channels of programming in the same bandwidth as a single HDTV signal. In other words, 480p is just more of what we already have with only a slight increase in image quality.
720p

720p (720 lines of resolution scanned progressively) is also a digital TV format, but it is also considered as one of the HDTV standards. As such, ABC, and now FOX, have committed to 720p as their HDTV broadcasting standard. Not only does 720p provide a very smooth, film-like image due to its progressive scan formula, but image detail is at least 30% sharper than 480p. As a result, 720p provides an acceptable image upgrade that is visible on both medium (32"- 36") size screens as well as larger screen sets. Also, even though 720p is considered high-definition, it takes up less bandwidth than 1080i, which is covered next.

1080i

1080i (1,080 lines of resolution scanned in alternate fields consisting of 540 lines each) is the most commonly used HDTV format, and has been adopted by PBS, NBC, and CBS (as well as satellite programmers HDNet, Showtime, and HBO through special feeds) as their HDTV broadcast standard. Although there is still debate as to whether it is that much better than 720p in the actual perception of the viewer, technically, 1080i provides the most detailed image of all the 18 approved DTV broadcast standards. On the one hand the visual impact of 1080i is lost on smaller screen sets (below 36"). However, with the increasing amount of large screen projection sets and custom front projection home theater setups, 1080i provides the detail needed for such large images.

However, the two drawbacks to 1080i are: 1. It takes up the most bandwidth of all the DTV broadcast formats. 2. It is an interlaced signal, which means that the displayed image is made up of lines that are scanned alternately instead of progressively as in 480p and 720p. However, if you have the bucks, Faroudja markets a processor that will actually convert a 1080i image into a 1080p image. This essentially removes any visible scan lines present in the interlaced 1080i image, resulting in very smooth edges. The results of this conversion are truly spectacular
for more inf check the source site at http://hometheater.about.com/cs/bef oreyoubuy/a/aahdtvfaqs2a.htm

Answered by raj u , an ibibo Master, at 12:35 PM on April 17, 2008

Well Saurabh HDTV stands for High Definition Television. High-definition television, or HDTV, is the ultimate home entertainment experience, bringing sound and picture quality to a whole new level. The image quality is 4.5 times greater than that of an ordinary television, creating lifelike images with crisp, high-resolution detail guaranteed to impress its viewers time and time again. HDTV or High Definition Television offers the highest quality picture available in the world of home entertainment. Instead of using the conventional 576 lines to plot a TV picture, HDTV uses 720 or 1080 lines. In addition, the pixels in each of those lines are closer. This results in a hugely improved picture quality, clarity and colour definition.


for more detail visit to this site:-
http://www.firstcoastaudiov ideo.com/hdtv.htm

Answered by Hemant Kumar , an ibibo Master, at 10:40 AM on April 17, 2008

well saurabh, HDTV is a new broadcast format for digital TV. It stands for High Definition Television, and facilitates the broadcast and display of pictures of a higher resolution than existing standards such as NTSC, SECAM and PAL will allow.
If your talking about the type of television signal you set is recieveing... like via cable, satellite, or antenna... then what digital is is TV broadcasted using computer language/code (digital information) instread of the normal kind of "analog" signal that TV has always been broadcasted in. These digital broadcasts take up a less space so you can fit several digital TV channels in the same space you can fit one regular analog TV channel. They often seem clearer (no noise or distortion) and may sound better as well.. but there isn't really much visual difference between clearly recieved full quality analog TV and Digital TV.

When something is recieved in HD (High Definition)... it is digital, but rather then simply a digital version of the regular quality TV we are used to.. it's a new type of TV quality/standard that operates at a higher resolution thus it had more detail/definition... sometimes several times as much.

To be considered 'HDTV-Ready', a TV set must meet certain requirements. For example, it must boast 720p, 1080i or 1080p resolution. The resolution number stands for the number of horizontal lines that make up the picture. The letters stand for 'progressive' or 'interlaced'. A progressive picture is similar to a cinema picture, with one still frame at a time displayed in rapid succession, giving the illusion of movement. Interlaced pictures send the picture in two halves but twice as fast, with the even-numbered scan lines followed by the odd-numbered lines. This method makes information easier to get to the receiver, but is a little less clear when something's moving quickly on the screen.

Another factor to consider is the aspect ratio. Standard televisions are of the 4:3 ratio, i.e. for every four units wide, a screen is three units high. You can thus calculate the screen's height by dividing its width by four and multiplying by three, e.g. a 20-inch-wide screen will be 15 inches high. However, some HDTV broadcast material, and a lot of pre-recorded movies, will be in widescreen format, which is 16:9 ratio. If you're buying a HD-Ready TV, make sure it can handle both with ease and effortlessly switch from one to another.


For more information visit the source site:

http://www.micromart. co.uk/features/article/default .aspx?id=23254

Answered by Uttam , an ibibo Master, at 9:47 AM on April 17, 2008

Ordianry TV, or SD (Standard Definition uses a resolution of 720x576 pixels.
This means that the screen is made up of tiny dots, with 720 dots in width and 576 dots in height.

Wheres HD (High Definition) TV has the screen made up of many more dots. There are for e.g. HDTV resolutions of 720p which has 1,280x720 dots on the screen, and 1080i which has 1,920x1,080 dots on screen.
Secondly, SD is more commonly a 4:3 aspect format, wheras all HDTV formats are widescreen (16:9)

Answered by Gaurang , an ibibo Citizen, at 12:22 AM on April 17, 2008