It is a 625 scanlines system that uses interlaced

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Unformatted text preview: nd computer monitors. Note that as compared to a computer monitor, a TV monitor costs less but flickers often due to the lower refresh rate. Types of Video Signals We saw in Figure 19.2 that a pixel is composed of RGB components. Human vision is more sensitive to variation in the luminance (brightness) than in the chrominance (color difference). To take advantage of such deficiencies in the human eye, light can be separated into luminance and chrominance components instead of the RGB components. For example, the YUV model separates luminance from chrominance via the following linear transformation from the RGB system Y = 0.30R + 0.59G + 0.11B U = 0.62R-0.52G-0.10B V = -0.15R-0.29G + 0.44B Where Y is the luminance component and (U, V) are the chrominance components. Based on these concepts of light representation, there are following two types of video signals (for both analog and digital videos) for storage and transmission: 1. Composite video signals. A composite video signal combines the luminance Y and chrominance C into a single stream to be stored and transmitted. Examples of analog videos using composite video signals include broadcast TV signals and VHS. Examples of digital videos using composite video signals include the D-2 and D-3 formats. 2. Component video signals. A component video signal separates the video into luminance Y and chrominance C streams. Component video signals are again of two types - the Y/C component and the RGB component. The Y/C component uses two separate channels to transport Y and C information, whereas the RGB component uses three channels to carry R, G, and B colors. Examples of analog videos using component video signals include Hi8 (it is of Y/C component type) and Beta SP (it is of RGB component type). Examples of digital videos using component video signals include the D-l, D-4, and D-5 formats. Out of the two, component video signals have better quality than composite video signals. Broadcast Television Standards The three main TV broadcasting standards are NTSC, PAL and SEC AM. All three are analog v...
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This document was uploaded on 04/07/2014.

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