Learn About High Definition Television

HDTV (High Definition Television)
Written by Cole Donovan, VTC Communications


Most people have heard the term “HDTV.” It’s a general term that encompasses a lot of information.   As we at Lemonweir look at making the jump to offering HDTV programming to our customers, we realize the obstacles that we must overcome.  As usual, our first priority is taking care of and informing our customers.   In the following you will find information to help you; 1. Understand what HDTV really is. 2. Help you decide if HD is right for you.  3. Help you understand the options you will encounter as you shop for an HDTV set. (Including which resolution to chose, screen size, quality in relation to affordability, and which technology to chose.) 4.) Understand how the HDTV experience benefits you as a consumer.

Let’s start with the basics!  HDTV stands for High Definition Television.  The reason the picture is considered to have a “High Definition” relates to how much detail is being shown on the TV.  A picture on a TV screen is made up of Lines of Resolution, both vertical and horizontal lines, that intersect each other to produce the picture.  The more lines of resolution you have the more detail you are going to have in your picture.  At each spot where a vertical and a horizontal line intersect each other, you have a pixel.  Depending on how high the resolution of your TV is, in combination with how high of a resolution of broadcast you are receiving, your picture can be made up of thousands to millions of pixels.  One common misunderstanding amongst new HD customers is that just because you have an HDTV doesn’t mean you are going to be seeing everything in HD. Also, just because you’re paying for and receiving an HD signal from your cable provider does not mean you are seeing HD on your TV.  In order to receive and watch TV in HD you must have both an HDTV set and an HD broadcast source as well as using proper HD cables.

So, what difference are you going to see when you watch HD, over your Standard Definition (SD) broadcasts? (SD or Standard Definition, is the term now used to describe all basic TV broadcasts.)  To put the difference in the easiest way to understand, we can look at the difference in the number of pixels making up each picture.  As we know from what was stated before, the higher the number of pixels the more detail we are going to see in the picture.  Looking at the SD broadcasts that we provide right now, you are receiving 480 vertical lines of resolution by 360 horizontal lines of resolution, which when multiplied gives you 172,800 pixels of resolution!  Sounds OK, right?  But, when you look at the average HDTV broadcast, you are receiving 1280 vertical lines of resolution by 720 horizontal lines of resolution, resulting in 921,600 pixels!  This HD picture gives you over 5 times the amount of detail in your picture!  Sounds good, but even if you have an HDTV and order HD broadcasting, not all channels are going to appear in HD. Only a limited selection of channels will be available for HD at the present time with any provider.

When the time comes to decide if ordering HD programming is the right choice for you, take into consideration three primary factors.  1. What channels are being offered in HD?  2. How often would I watch those channels?  3. When balancing the difference in cost of HD program with your interest in those channels offered in HD, is it worth it to you?  Another factor that could be added to that list, but requires enough room for its own discussion, is relating the cost to quality analysis of buying a new HDTV set.

In your venture into HD, once you’ve made the decision to take the HD leap, you will find yourself surrounded by decisions, resolutions, 720P, 1080i, 1080P, salespeople, refresh rates, response times, countless brands and models, extended service guarantees, surround sound systems, DLPs, plasmas, LCDs!  And all you want to know is what TV to buy!  Well, that’s why you’re reading this, and that’s why I’m writing this.  Narrowing down your decision when looking at HDTVs is really no chore at all!  Let’s start with choosing from the three technologies you are going to find; Rear Projection, Plasma and LCD.

The type of TV you purchase is very much going to be decided for you by the type of room it is going to be in.

Factor 1: Size.

Bulk: What do you have room for?  Rear Projection TVs (Referred to as Projos from here on out) are going to be the monsters you see with deep backs on them ranging to over 1.5 feet deep, though some brands are developing thinner models.  Some Projos actually have a large base attached to them, with wheels on the bottom and require no additional TV stand.  Furthermore, you will also be hard pressed to find a Projo under 46” screen measured diagonally.  Do you have room for something that bulky or would a Flat-panel better fit your needs?  You have LCD and Plasma flat panels available to choose from, around 4-5 inches deep without a stand, and wall mounting is also an option.  If you aren’t mounting, be sure get the dimensions of any base that will be attached to the bottom of the TV, to allow you to by a stand with the proper surface area for the TV.

Screen Size: The size screen you want on your TV relates to how many feet you will be sitting away from the TV.  Starting at about a 30” HDTV, at 5’ in viewing distance, add 3 inches of screen for each additional 1.5’.  Now this is a general guideline, but the true test for appropriate size is, number one, “Is the TV so small you have to squint?” and two “When standing at the approximate distance away that your seating area, can your eyes comfortably rest while watching the TV, or is the TV so big your eyes have to dart around to see the entire screen?”

Factor 2: Lighting.

Did size narrow your choice at all?  Well, certain TVs are going to have very reflective fronts on them.  For example, plasma TVs have a glass panel on the front of them that can create an annoying glare off them in the day time.  There are some newer models of LCDs and older models of Projos with the same reflective characteristics.  Are there going to be windows causing you problems? Shop carefully on this issue as certain LCD and Projo models will have an antiglare surface for those troublesome rooms.

Factor 3: Viewing Angle.

This limitation in seating arrangement is going to apply almost exclusively to your Projo TVs.  With the workings of a Projo, you have a projector in the TV which is either reflecting the picture off a series of mirrors, or multiple LCDs, showing the picture on the front screen, much like a movie theater projector, but from behind.  This results in a faded picture when sitting at extreme side angles, or if you have the TV too high or too low in relation to your seating area.  Higher end products will have stronger bulbs and projectors to offset this limitation.

Now, hopefully keeping those three factors in mind, your decision will be easier to make as we begin to look into the specifications.  Roll up your sleeves, some of this is going to get a bit technical, but are very necessary issues to be educated on, in order to produce the most satisfying HD experience.

Factor 4: Resolution.

A: As you shop you are going to see seven primary reference terms for a TVs maximum capable resolution.  480i, 480P, 720i, 720P, 768P, 1080i, and 1080P.  The first thing to notice is the following “i” or “P” after each number.  Referring to what we’ve learned on resolution, you have the number of lines of resolution, as a picture is being produced. Those lines are constantly changing the information they are sending, just as the picture is always moving as you watch it.  The refreshing of those lines to keep the picture flowing smoothly, is a scanning process.  This scanning process can be done in one of two ways.  One, is the “i” standing for an interlaced scanning process during which the even lines of resolution are first refreshed, and then the odd lines of resolution.  Two, is the “P” standing for a Progressive scanning process, during which all lines of resolution are scanned simultaneously.  The interlaced process is considered inferior, resulting in less fluid motion that the better Progressive scanning process.

B: When referring to the number associated with the letter in the resolution, as we’ve already discussed, the higher the number the more detail you are going to be capable of showing.  The number used, simply refers to the number of vertical lines or resolution leaving out the horizontal lines, and is used as a short hand method, as opposed to writing out the entire resolution.  480i refers to our SD broadcasts, which we discussed before, and is our normal TV.  480P is your standard TV channel scanned more efficiently, but is not HDTV, and should be disregarded when shopping for HD.  720i is the interlaced version of your standard 1280x720 HD resolution that we used in our earlier pixel calculations.  The “i” version is rarely seen with 720, as you will predominately see the 720P, which is the standard for HD cable channels.  Venturing into 1080i and 1080p is taking a step beyond most cable broadcasts at the present date, but become an interesting dilemma when purchasing your TV.  1920x1080 is the resolution that is the next step in high definition, and the only true source of 1080P offered in stores will be Blu Ray DVD players, a rather pricey expenditure, but a worthwhile demonstration to see at any store, and an unmatched optical adventure for any movie fan!  Blu Ray DVD is also built into Playstation 3 video gaming units.  The 1080 resolution represents 2,073,600 pixel of resolution and detail!  Purchasing a 1080 TV prepares you for the future, as the life span of HDTVs grows and grows and becomes more realistic.

Factor 5: Refresh Rates.

This is a number measured in fractions of seconds, that relates to how fast a TV can refresh the picture on the screen.  The easiest way to understand this is to think of a strobe light.  When a person is standing in a room with a strobe light, do their motions look smoother as the strobe light goes faster or slower?  The answer is faster, and the same is to be said with a television.  The faster the refresh rate, the smoother and more fluid the picture is going to flow.  This in combination with the upcoming response time, is very important for any scene with a lot of action or for sports.

Factor 6: Response Time.

Response time relates in very close proximity to your refresh rate, but is just a bit different.  In thinking about this, imagine a hockey game on the TV and the speed at which a hockey puck can travel.  Remember those pixels we talked about earlier?  Well, as an object moves across a screen, each one of those pixels has to turn on and off, showing the appropriate colors to keep up with the object in motion.  If a TV has a slow response time, that object, in this case a hockey puck, will leave a color trail behind it. In this case a gray trail, as the pixels change from white to black and back again.  As with refresh rates, the faster the better with response times.

Factor 7: Contrast Ratios.

High definition is great and can offer a great amount of detail, but all your cable provider can do is send you a perfect pristine picture. Beyond that, it is up to your HDTV and its capabilities to show the picture optimally.  Contrast ratio is a big factor in the range of color your HDTV is going to be capable of giving to the picture.  Your standard plasma TV gets its great reviews based on a 10,000:1 contrast ratio.  Having this high a contrast ratio offers an amazing range of colors and truer blacks.  If you want to measure the quality of contrast ratio on a TV without relying on an information card, look at its blacks.  A TV with a low contrast ratio will not be able to show a true black, or for that matter a true white, but simply darker and lighter shades of gray.  This in turn, gives TVs with a higher contrast ratio not just sharper colors, but more defined or crisper lines in your picture.  It used to be that only plasmas had reached the 10,000:1 plateau, but that is no longer so. As you shop, keep an eye open for this on a case by case basis.

Factor 8: Pricing and Quality.

You may read this and say, “Why would I ever need to understand all of this ‘mumbo jumbo’?!”  Well, beyond general scholarly pursuits, they all play into you being an informed consumer, giving you power as you enter the buying market.  Many times your best interest may not be in the forefront of a salesperson’s mind.  They may get benefits for selling certain TVs, commission, clearance items, TVs that may not be the best quality, but they have such an issue getting rid of, and are just waiting for an unsuspecting customer to ditch it off on.  If you read this and take the time to understand it, that customer will not be you!  When you see one TV for twice the price of another that may look the same on display, you can look at these factors.  From resolution to response times, to the situation of your room, you are going to know where a TV falls short. Decide what fits your needs, from money to quality, and really understand the purchase you are making, without having to rely on a salesperson’s weighted opinion.  HDTVs is one area of sales where very often you get what you pay for, and hopefully you now understand the factors that set different TVs apart without getting buried in brand names.

What am I going to need to set this up when I get home?

The world of HD has its own cables that are required to be used in order to transport and display HD programming properly.  The reason special cables need to be used, is because as we talked about before HD programming has a lot more detail, and with that detail it means there’s is going to be a lot of information that needs to pass from your cable box to your TV. Regular video cables are not capable of that.  Also, all HD programming is capable of being played in Surround Sound, though it isn’t required.  I will break down the different cables you will see and what they mean to you.

Component: Component cables are used strictly for video only.  They are 3 plugs colored Red, Green and Blue.  Red, green and blue are the primary colors of the color spectrum and component cables transfer your picture accordingly which makes them capable of transporting HD.  Because this is a video only cable you will also need audio cables, standard red and white stereo audio cables will suffice unless you decide to go with Surround Sound in which case you will need one of Surround Sound Audio Cables listed below.

DVI: This is a fairly outdated HD cable, that carries video only and is not recommended.

HDMI: This is the latest and greatest cable available.  It is capable of transporting full 1080P HD. It couples both the highest quality video cable available and carries surround sound audio on the same line.

Digital Coaxial Audio/Optical Audio: these are the two, stand-alone, Surround Sound audio option cables.  The one you choose will typically be defined by the capabilities of the surround sound system you are working with or the device (Cable box, DVD player, etc.) you are working with.

What are my non-HD programs going to look like on my HDTV?

A big difference to understand between HD and SD programming is that they are in different picture formats.  You will notice as you look at HDTVs compared to your old sets, they all seem shorter but wider, and that is a very accurate description.  HD and SD have different Aspect Ratios, meaning that the ratio of height to width of the picture is different.  HD has a 16:9 width to height ratio, while SD has a 4:3 ratio.  What this means to you, is that when you watch a non-HD program on an HDTV, you will have two choices; 1. Stretch the picture to fit the screen, which in turn will make the people on the TV look shorter and wider, or 2. Watch the show with a black bar on each side of the picture leaving the picture in its normal state.  This factor makes many people lean towards a little bigger TV to compensate for the loss of picture on an SD program.

Now That I’ve Learned All This, Tell Me About the TVs!

Plasma: Plasma TVs are a flat panel display using a gas panel with thousands of xenon and neon cells to produce their picture.  They produce a picture known for its sharpness and crispness.  The colors aren’t necessarily bright, but work very well in darker rooms.  The speed in which the gases used to produce the picture respond and refresh, work at remarkable rates, producing a very smooth picture, great for any type of viewing.  Plasmas got a bad rap for in their first years as they had a lot of burn in issues, where a station identification marker or channel ticker would burn in the lower corner or along the bottom of the screen.  It is debatable by brand, but many of the nicer models have found ways to work those problems out.  Plasmas are, when it comes to the screen itself, disposable technology.  When the picture is gone, or the gases are gone the TV is as good as gone.  The lifespan on these varies greatly by brand. Better brands use more gas or deeper cells, and to get an accurate picture of the lifespan, you will need to consult your salesperson.  As stated before, these TVs do have a reflective glass surface as well.  Plasmas are less common to be available in 1080P, but the availability is increasing.  Transporting can also be tricky, as they cannot be tipped at any deep angle or the gas panel can be damaged.

LCD: If you go LCD you cannot skimp.  This is where all your refresh rates, response times, and contrast ratios truly come into play.  Buying a poor LCD can spoil the entire HD experience.  LCDs are very attractive to customers as they are low maintenance, often have antiglare screens, can be found in a wide range of sizes, very rarely burn in, are readily found in 1080P, and are flat panels.  The down sides are going to apply only to lesser models, as by nature the LCD panel refreshes and responds at a far slower rate than any other TV.  Poor LCDs can be a nightmare for someone watching any kind of TV, as they can leave trails and have very blocky pictures.  Better brands equal better video processors and higher contrast ratios, along with faster refresh rates and response times.  A nice LCD can be a dream come true for an HD buyer, but be prepared to pay for it, out of pocket that is.  These TVs are also considered disposable technology.

Projo: For those without grand dreams of saving space or hanging the TV on the wall or above a mantle, these TVs can be a bargain buyer’s dream.  Not only can you get larger sizes at lower prices, but you can easily find 1080P, along with amazing refresh rates and response times.  Though large and bulky they are amazingly light, as the inside is mostly dead air for the projector to work.  Another upside is that everything inside of these TVs is fixable or replaceable.  As it is a projection system, these TVs do use bulbs which have a far shorter lifespan, but they are easily replaced and cost around $200, which you will look at spending, depending on usage, every 3-7 years.  As mentioned earlier, at extreme viewing angles the picture can appear faded, so these are meant for mostly straight on seating.

Looking for additional information and comments and review from other consumers?  The Internet offers several information and conversational websites full of information and opinions.  Various consumer reporting magazines are also available.  Please remember to take opinions as opinions and treat facts as facts.


We hoped the article helped you better understand the confusing world of HDTV. We’re your neighbors and we’re here to help you.


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