Tuesday, July 6, 2010

How Does A Television Work

How does a television work is a common question asked by people of all ages. Very young children will carefully examine a TV set from all angles and then ask how all the people get inside the TV. While the rest of us are too sophisticated to ask that question, the answer to How does a television work is a mystery to most people.

The answer to How does a television work is both simple and complex. The basic concepts are pretty simple. But how they are implemented is pretty complex. So let�s take a look at the basics. The first thing is to convert the picture into a video signal. Next you need to transmit that signal to a device capable of displaying it. The receiving device turns the signal back into an image and displays it on the screen for you to see. Simple� right?

Converting images to signals
The first part of the answer to How does a television work is digitizing the image. To digitize a picture you must break it down into lines composed of dots (or pixels). The image is �scanned� using a device that can break the image into lines. Now that you have the lines of data, you assign a value to each colored pixel using a predefined color palette. All color in the palette are made of various intensities of the three primary colors of red, blue and green. Then the information is encoded into a data stream called a video signal.

Transmitting the images
The second part of the answer to How does a television work is transmitting the image. The data stream is transmitted to a receiving device (in this case a TV set). The transmission is usually by means of ordinary radio waves that are broadcast through the air. However, it can also be transmitted by electrical impulses or even light pulses if it is being set over cable television. No matter which method is used, video signals use up a lot of bandwidth for transmission. Bandwidth is the physical capacity of the transmission media to carry signals. If you visualize each different frequency of sound waves as individual one inch diameter pipes laid side by side, bandwidth is the number of pipes needed to carry the entire video signal so it arrives at the receiver fast enough to be reconstructed in real time.

Displaying the images
The last part of the answer to How does a television work is displaying the image. Basically you just reconstruct the signal by reversing the process used to digitize it. The more pixels you use when scanning the image, the more the reconstructed image will look like the original image. Instead of a scanner, you use an electron gun to shoot electrons at the screen that correspond to the correct colors so the phosphorous on the inside of the picture screen will glow the right color. I hope that the simplified description in this article answers the question how does a television work.

No comments:

Post a Comment