For the past 40 years televisions signals have employed a standard known as NTSC (National Television Systems Committee) for production, transmission and display. The NTSC standard is known as analogue signal in that it is created with continuously varying voltage levels or electrical waves, which may be adversely affected by every step in the production -distribution process. To conserve the limited transmission spectrum, the color portion of the signal and the luminance (black and white image) are combined in the production stage and retained in this composite form until separated at the television receiver into the primary components of red, green and blue (R,G,B) at the picture tube.
DTV is the new generation of television. DTV signals are generally recorded, distributed and transmitted in a digital component format. Being digital, the signal generally experiences minimal loss of quality from the studio or mobile cameras to the homes. The color is more faithfully reproduced through the entire process from the originating R,G,B components in the camera to our home television displays. This ensures sharper pictures, and greater color fidelity. Potentially studio origination quality can be delivered to the home without transmission or distribution losses. And this can be done at varying levels of picture detail depending on the content needs, broadly described as Standard Definition television (SDTV), Enhanced Definition television (EDTV), and High Definition.
The North American DTV standard known as ATSC (Advanced Television Systems Committee) is basically a highly compressed stream of 1’s and 0’s, known as bits, which represent the pictures, sound and data associated with the television signal. These bits are then converted into pixels (short for Picture Elements), which can be thought of as a single dot of light on the TV screen. The greater the number of pixels, the sharper or better defined the picture will be. In its “finest” form HDTV can display up to 10 times as many pixels as most analogue televisions.