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Welcome to the world of high definition!! This page will give you everything you need to know to enjoy a fabulous television experience with better, wider pictures and much improved sound!

Receiving High-Definition Signals

If you're going to get the most out of your HDTV purchase, you'll want to understand a few basic things about high-definition TV signals. High-definition signals in the United States are transmitted digitally. It is possible to receive these signals from a variety of sources, including over-the-air, cable and satellite. Receiving a digital signal means you are getting a perfect copy of what the television station, cable or satellite distributor is transmitting. If the digital signal becomes weak, you won’t see any picture instead of the fuzzy picture you’re used to with weak analog signals. It’s important to realize that not all digital signals are in high-definition, as standard definition television pictures can also be transmitted digitally. In fact, most of the programming we receive digitally over-the-air, or through digital cable or satellite, is transmitted in standard definition format. Fortunately, the amount of high-definition programming increases almost daily!

Over-the-air digital signals

One of the best ways to receive digital signals is over-the-air. The real beauty of digital over-the-air reception is that the signals are free, just like standard broadcast television. Mos new HDTVs come with an integrated HDTV decoder (often called "HDTV Built-in"); all you need to do is hook up an antenna and you're ready to receive over-the-air signals. If you buy an HDTV that does not have an integrated decoder (usually called an “HDTV Monitor” or “HDTV Ready”), receiving over-the-air digital signals will require you to have a decoder, also known as an HDTV receiver or “set-top box.” In this case, the antenna connects to the decoder. The box breaks down the digital signal and sends it to either the component video, DVI (Digital Video Interface) or HDMI (High-Definition Multimedia Interface) input on your HDTV. Component video inputs can be identified by the letters Y, Pb and Pr. A DVI connection is a single cable that sends the video signal from the set-top box to your television display. HDMI (High Definition Multimedia Interface) is similar to DVI, but carries both the video and the digital audio signal. Unless you are using an HDMI connection, you will also want to get a digital audio cable to connect from the set-top box or HDTV to your Dolby digital capable audio receiver (see the section on Sound on this page). These cables can be either optical or coaxial.

Receiving over-the-air digital signals requires use of an an antenna. All the transmitting towers for the Twin Cities are in Shoreview, so choosing the right antenna for your location is important. Excellent information on this subject can be found at AntennaWeb.org. Many people living in the Twin Cities metro area may be able to pull in digital signals with an indoor antenna. Outdoor or attic antennae provide can provide even better reception.

The Twin Cities has excellent availability of over-the-air local channel digital signals (see Local Channels).

Digital Signals from Cable and Satellite

High-definition signals are also available from cable and satellite providers. Obviously, you still need to have an HDTV to get the high-definition signals. If you are going to receive your programming from cable, the cable company will provide a high-definition set-top box to receive their programming. These boxes often have component video outputs, and many have HDMI as well. Set-top boxes supplied by the cable company will generally not, however, receive over-the-air signals. This may change in the future, as retransmission conflicts between cable companies and broadcasters are leading manufacturers to explore over-the-air receivers integrated with cable high-def cable receivers. All the Twin Cities' cable companies have high-definition local channel availability. Some HDTVs are called "Digital Cable Ready." They have a built-in card slot designed to accept a CableCARD. The CableCARD is a removable security card that allows the TV to receive high definition and other digital cable programming without the need for a separate set-top box. CableCARDs can also be integrated into high-definition digital video recorders, such as the TiVo Series3.

If you are going to receive high-definition signals from satellite (DIRECTV or DISH Network), it will be necessary to have a set-top box or integrated HDTV capable of decoding the signals from that satellite service. These boxes generally are also capable of receiving over-the-air transmissions. Both DISH Network aand DIRECTV broadcast Twin Cities local digital (HD) signals. Check out the Cable/Satellite page of this website for further information.

High-Definition Picture Formats

If you have looked at ads for HDTVs in the newspaper, you have probably seen the terms 1080p, 1080i and 720p. 1080i and 720p are the broadcast high definition formats currently in use in the United States, while 1080p is presently available only on Blu-Ray high definition discs. The numbers refer to the number of horizontal lines that can be displayed on the television screen. The “i” stands for interlaced and the “p” stands for progressive. Standard-definition television signals are transmitted in 480i format. This means that the picture has 480 horizontal lines and is displayed using interlacing. Interlacing refers to displaying odd numbered lines first followed by even numbered lines. The odd numbered lines are displayed in the first 1/60th second, and the even numbered lines in the next 1/60th second. Therefore, a whole new image is displayed every 1/30th second. Progressive display means that the lines are displayed sequentially, meaning a whole new picture every 1/60th second.

The broadcaster determines the high-definition format of a broadcast program. For example, NBC and CBS have chosen 1080i as their format of choice. ABC, ESPN and Fox have chosen 720p. There is no “best” high-definition format. If there is a consensus on this issue, it is that 1080i is superior for slower moving action, and 720p is superior for faster moving action such as sporting events. Suffice to say that both high-definition formats are a big improvement over 480i or 480p programming.

Your HDTV display will also have its' own "native format," which can be as high as 1080p. It doesn't matter what high-definition format the broadcaster is sending the signal in, as your set will convert the signal to its native resolution.

Aspect Ratio

High-definition pictures are broadcast in 16:9 aspect ratio. This means that the ratio of width to height of the picture is 16:9. Standard definition television pictures are broadcast in 4:3 format.

Comparing Broadcast Formats

One way to compare broadcast formats is to look at pixel counts and total pixels. Pixel is an acronym for picture element. Comparing pixel counts and total pixels is a good way to look at how much information is contained in each picture. A comparison of pixel counts and total pixels between the various formats is provided in the table below:

The effective resolution is not quite as simple as comparing total pixels. Every 1/30th of a second the 1080i format has displayed one video frame made up of two 1,036,800 pixel fields. During that same 1/30th second period, the 720p format has displayed two complete video frames of 921,600 pixels each. The 720p format has a total pixel count of 1,843,200 during that 1/30th second period, while the 1080i format will vary anywhere from 1,036,800 pixels to a maximum of 2,073,600 pixels, depending on the motion of the image between the interlaced fields. The only time the interlaced format displays its maximum 2,073,600 pixels is during a still image.

Sound

High-definition programs not only have better pictures, but better sound as well. Many high-definition programs are transmitted with Dolby Digital 5.1 Surround Sound. This is the same sound format used on most DVDs. In this sound format there are 5 separate full frequency sound channels (center, right, left, right surround and left surround) and a subwoofer for low frequency effects. There is a vast improvement in sound quality using Dolby Digital 5.1 compared to standard television sound. Most AV recievers are capable of processing Dolby Digital signals. Connections from the HDTV receiver or integrated HDTV to the AV receiver are best made with digital coaxial or digital optical cables. Most newer HDTVs have HDMI interfaces, which allow the transmission of sound and video signals in one cable.

Types of HDTV Sets

Direct View:

Direct view HDTV sets are similar to the televisions we all grew up with. These televisions use an electron gun to fire electrons at a phosphor-coated screen. The screen has color dots that fluoresce when excited by the electron beams, thus producing the colors we see. The major limitations of direct view televisions are size and weight. Given that lighter-weight displays with equal or superior quality are available, there is little reason to consider purchasing a direct-view HDTV, and these sets are disappearing from store shelves.

CRT Rear Projection:

These televisions use three different cathode ray tubes (CRTs) to display a picture on a mirror, which then bounces the light up onto the screen from inside the television set. The CRTs are usually located near the bottom of the television set. These sets have a somewhat limited viewing range. You must be seated at the height of the screen and not too far off to the side to see the brightest image. These sets are rapidly disappearing from the marketplace, but may be available as true bargains if you're on a tight budget.

LCD Rear Projection:

LCD sets use a projector lamp that focuses light through three small LCD panels. These panels are made up of small sealed pixels filled with liquid crystal compound. When a tiny charge from a small transistor is applied to a pixel, the crystal begins polarizing the light. This results in a sort of an on/off switch.LCD projection sets differe from LCD flat panel sets (see below).

DLP Rear Projection:

DLP is a new technology developed by Texas Instruments, which displays light from an array of tiny mirrors contained on a chip called a Digital Micromirror Device (DMD). This chip is the size of a thumbnail and contains a huge number of microscopic mirrors, which tilt as many as 5000 times per second to either reflect or not reflect light. Each mirror corresponds to one pixel. This technology creates a highly detailed image by combining with a color wheel to shine one of the three colors of light on the DMD chip. When the pattern of the mirror on/off switches is combined with different colors of light from the color wheel, a very bright and detailed image results. This image is then projected onto the screen.

LCoS Rear Projection (including HD-ILA and SXRD):

The acronym LCoS stands for Liquid Crystal on Silicon. Liquid crystals are coated onto a silicon chip, which uses a reflective (aluminized) layer to reflect light. This reflective design greatly increases contrast and eliminates any dotted "screen door" effect that can be seen in transmissive LCD chips. LCoS sets are inherently progressive scanning. Currently available LCoS sets can display up to a full 1080p picture.

Plasma Flat Panel:

The biggest advantage of plasma screens is that they are thin and lightweight, so that they can easily be mounted on a wall. Plasma screen televisions create their picture by igniting small amounts of gas contained in cells, which then produce ultraviolet light. This light shines on another layer of colored phosphors creating visible light. The resolution of plasma screen TV’s varies by manufacturer and model. Plasma screen televisions also use progressive scanning. It appears that plasma displays are being gradually abandoned by manufacturers in favor of LCD falt panel displays.

LCD Flat Panel:

LCD flat panels have in the past been more expensive than equivalent-sized plasma panels, but prices continue to drop. They are about an inch thinner than plasma screens. The one advantage over plasma is that the displays tend to be brighter. The disadvantage is that black levels can be better achieved by plasma displays, and that these sets may not display motion as well as plasma.

Front Projection:

Front projection televisions can use LCD, LCoS, DLP or CRT technology. These sets offer an opportunity to have very large theater-like displays in your home. The most common front projection technologies are LCD and DLP. The choice should be made on the basis of price, light output, contrast, resolution and available inputs.

DVDs and HDTV

Many people buy their first HDTV just to watch standard definition DVDs. While we consider this to be shocking under-utilization, HDTV sets provide two significant advantages when watching DVDs. The most obvious is the widescreen picture, which can be displayed fully on a widescreen HDTV. There is some minimal letterboxing even with widescreen format DVDs, though, because the aspect ratio of film is not quite the same as HDTV. The second advantage is the improved picture that results from use of a progressive scan DVD player. The progressive scan feature limits the number of digital to analog and analog to digital conversions the image must undergo, thus providing less degradation of the signal along the path. It does so by de-interlacing the video in the digital domain and assembling the original 24 frames per second in a progressively scanned, 60 frame per second sequence prior to the conversion to analog. This not only creates a more "film-like" image, but avoids the need for additional processing (line doubling in most cases) in the monitor to increase display resolution.

High-definition DVDs have recently become available. Up until recently, there were two competing formats for high-definition DVDs. One was called the Advanced Optical Disk, informally known as HD-DVD. This format has now been abandoned as the loser in the "format war". The other is called the Blu-Ray disc. Blu-Ray players are now available everywhere. Sony is also shipping the Playstation 3 with an integrated Blu-Ray drive. The availability of high-definition discs is increasing weekly.