Pixels A pixel is a PICture ELement and it actually is the smallest resolvable square of an image. Each picture in fact consists of 3 even smaller dots of the colors red, green and blue. Together these 3 dots can create all the colors you see on your TV. A pixel is small enough for your eyes to think that they are 1 dot on the screen and even though each pixel in fact shows 3 different colors your eyes perceive them as 1 color.

To give an example: It may sound strange but when you see the color white on your TV, each pixel is showing all three colors red, green and blue in full intensity. Together these 3 colors make up the color white. Varying the intensity of the 3 colors results in the ability to create all the colors we can see.

DTV improves the resolution of your TV by putting more than 4 pixels in the same space that analog TV uses for 1 pixel. Also in Digital TV each pixel is exactly square. Analog TV uses a slightly higher than wide pixel which is why sometimes analog TV shows distortions of the image.

Resolution The resolution of an analog television screen is very low. The NTSC standard sets for 486 active lines where DTV is set for 1080 active lines. The number of pixels on each line is only 720 where Digital Television can go as far as 1920 pixels per line.

You may not have noticed that analog TV really has a low resolution and with that a low image quality. The reason for this is that TV is generally a moving image which results in your eyes not having the time to detect the low quality of the images. Your brain will simply fill in the blanks. Perhaps you have watched a program on (analog) TV about the internet and they showed a computer screen to show a website. If you have, you probably noticed the extremely poor quality of what you saw compared to what you see on your computer monitor. Your computer monitor uses a much higher resolution than analog TV.

Widescreen As a result of TV the movie theaters had to come up with a solution to compete with TV at home. The viewing experience in the movie theater had to be better otherwise nobody would care anymore to go to a movie theater. They tried many things but the best working solution was a wider screen.

Because the way we see is a more rectangular wider view, a wider viewing area gives much more visual information than the squarer image of analog TV (ratio of 4 wide by 3 high). DTV and a more specific version of it, HDTV, uses a ratio of 16 wide by 9 high. This wider screen improves the viewing experience to match the format used in the movie theaters.

Sound Analog TV can handle 2 audio channels, so the best you get out of it is plain Stereo. DTV can handle 5.1 audio channels and thus gives the possibility to have your own home theater with surround sound to create a movie experience in your house.

Comparison The advantages of DTV over analog TV are really as simple as this:
Better picture and better sound are the obvious advantages of DTV, but why is the fact that it is digital also an advantage? Its true that the same result can be achieved with an analog system. For that you dont need to go digital. Japanese HDTV for example is transmitted over an analog signal. But there are some other advantages to digital systems.

Digital Advantages There are some good reasons for the United States to go completely digital. The amount of data that can be transmitted for example is a very important one. You can stuff a lot more data into a digital signal than into an analog signal. Digital signals can also be used to transmit other data than just images and sound.

And one other very important advantage is that the information transmitted doesnt deteriorate over distance. Analog signals lose quality over distance while a digital signal doesn't lose any quality.

Bandwidth With a higher quality image and sound DTV uses much more data than analog TV. But how are we going to squeeze so much more data into the same amount of bandwidth that an analog TV channel uses?

Broadcasters in the United States are not allowed to use more bandwidth for 1 channel, so they somehow have to squeeze the additional data into the same channel.

The answer you may already have heard of: MPEG-2. Because the information is digital, the data can be compressed into much less bits. The receiver has to decompress and the original data is back. MPEG-2 can reduce the amount of bits by a factor of up to 55.

Consider that standard analog TV has a resolution of 378,000 pixels where Digital Television can go as high as 2,073,600 pixels. A compression factor of 55 is more than 10 times than required so MPEG-2 is more than enough to squeeze much more data into the available bandwidth of a standard analog TV channel.