I’m sure a lot of you out there have heard the term HDTV. TV’s are getting more and more sophisticated as the years go on and so are the terms used to describe them. So let’s take a little stroll into HDTV land and see what we can come up with.

First of all, the term HDTV stands for High Definition TeleVision, and it means that the picture displayed on the screen is usually crisper and clearer that your standard tube TV. Let’s figure out what some of the differences are between the two. I am going to keep this as simple as I can, for there are many different characteristics that make up each type of TV.

Your standard TV has the following attributes:

Interlaced image drawing

4:3 aspect ratio

480i resolution

HDTV sets have these features:

Progressive scan image drawing

16:9 aspect ratio

480p, 720p, 1080i, and 1080p resolutions

Now I’m going to try and break each of those terms down so you can understand what they mean, and then how they apply to the different types of television sets. I’ll start with image drawing.

Interlaced means that the picture is drawn to your TV screen every other line, and then the TV goes back and draws the remaining lines to fill in the picture. This happens every second, and you can imagine that leaving some of the picture out for half of a second can make your picture quality look a little dull. Sounds a little confusing? Maybe drawing it out will help. NOTE: TV’s draw in a vertical fashion, but that wouldn’t look right as a drawing, so I’m going to do it with horizontal lines to illustrate the principle of how it works.

An interlaced image will begin drawing like this:


Notice this space?


And this one?


After those lines of the picture are drawn, your TV will go back and fill in the lines like this:






Don’t worry, progressive scan is easier to understand and makes your picture quality better. Progressive scan draws the entire picture as a whole to the screen every second. See now that wasn’t so hard.

Your aspect ratios are what shape the picture will be, 4:3 is a square that is slightly taller than it is wide, 16:9 is a wide rectangle, or widescreen. There is a more technical explanation for aspect ratios but we are going to keep it simple for now.

Finally you have your resolutions, feel free to glance back up and take note of the numbers listed above in the beginning of this post. The numbers 480, 720 and 1080 all represent how many vertical lines the TV will draw each time it updates the picture. The letters that follow them, i and p, stand for interlaced and progressive. Aha it’s all starting to make sense now isn’t it? Basically if your TV has 1080i, it will draw 1080 lines on the screen, in a half and half pattern as I explained before. 1080p however, will draw all 1080 lines on the TV at once!

For those of you brave enough to put this knowledge to the test, here are some links for you to learn more in depth about the topics discussed in this post

Wikipedia’s entry for 1080p

Wikipedia’s entry for HDTV