nals are usually digital and encoded and compressed. They require special antennas pointing in specific directions to pick up specific satellite signals. These signals must then be decoded or unencrypted and decompressed to view on a TV set. This usually requires special equipment and most satellite TV services operate on a pay per service fee.

Cable TV

Cable TV is another way to receive TV broadcasts. Instead of the TV signals being transmitted through the air, they are collected from a certain point, and sent from the cable company directly to your home via cable. Just like a phone line is laid from the phone company to your home, so is cable TV. There are many types of cables that are used including copper or fiber optic and the signals that the cable company sends to your home usually are encoded and or compressed. Most homes require technology to unscramble and decompress the signal to view the TV signal on their TV set.

TV Technology Elements

There are many parts to a TV set that allow you to view video images and reproduce audio signals; they include the cathode ray tube, the color process, and the TV Antenna.

Cathode Ray Tube

The cathode ray tube generally called a CRT is a vacuum tube. Inside this vacuum tube are electrons that move rapidly from one field to another (negative to positive). These electrons stream from a positive to negative electric field onto a screen that is coated with phosphor. Phosphor glows when these electrons hit the screen creating an image. TV's create images by creating small pixels or dots on the screen. Thousands of glowing dots on a screen in a certain pattern create a picture. These dots are called pixels and the more pixels on the screen, generally the higher the resolution and better the image quality.

Color Process

Within the cathode ray tube is a beam that shoots electrons onto a screen which is coated with Phosphor. While a black and white TV has one beam, color TV's have three beams; red, blue and green. Color TV's also have one screen which you view your image from, but behind this screen is a sheet of phosphor, black and white TV's only have one sheet of phosphor, color TV's have three sheets of phosphor; red, blue and green.

How to Create Color

The color TV creates colors by mixing both the three types of color beams (red beam, blue beam, and green beam) and the three types of color sheets (red sheet, blue sheet and green sheet). If you would like to create the color blue, the blue beam will hit the blue sheet in the back of the TV screen, for red, the red beam hits only the red sheet. To create yellow, both blue and green beams hit both blue and green sheets. White is when all color beams hit all color sheets. Black is when no beams fire at the sheets.

Antenna

An antenna is usually required to pick up and receive TV broadcast signals. TV broadcast signals travel a long range and face many obstacles such as walls and other obstructions. In order to capture a strong TV broadcast signal, an antenna is used. Antennas are usually composed of materials that can capture radio frequencies (usually

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