7 features of the two hdtv standards apart from

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Unformatted text preview: ideos using composite video signals technology. They mainly differ in the way they encode the chrominance signal. They also differ in screen resolution and frame rate. Their characteristic features are briefly described below. 1. NTSC. NTSC stands for National Television Systems Committee. It is a 525 scanlines system that uses interlaced scanning technique with a refresh rate of 29.97 frames per second. In NTSC, the luminance signal is called the Y signal, and the chrominance signal is amplitude modulated onto the color subcarrier at two different phases - the / (in-phase) value at 0° and the Q (quadrature) value at 90°. NTSC is used in the US, Japan , and some Asian countries. 2. PAL. PAL stands for Phase Alternating Line. It is a 625 scanlines system that uses interlaced scanning technique with a refresh rate of 25 frames per second. In PAL, the composite video signal operates on the YUV model, where Y is the luminance component and (U, V) are the chrominance components. In PAL also, the chrominance signal is transmitted on a two-phase amplitude-modulated color subcarrier but it uses a more complex process called Phase Alternating Line, which provides more bandwidth for chrominance modulation, yielding better color resolution. PAL is used in India and Western Europe (except France). 3. SECAM. The SEC AM system, developed in France, stands for Sequential Couleur Avec Memoire. It is a 625 scanlines system that uses interlaced scanning technique with a refresh rate of 25 frames per second. In SECAM, the chrominance signal is transmitted using a frequency-modulated color subcarrier, transmitting one of the color difference signals on every other scanline, and the other color difference signal on alternate scanlines. It also has better color resolution than NTSC. SECAM is used in France, Eastern Europe, Russia, and Middle East. A summary of the characteristic features of the three analog TV signal standards is given in Figure 19.6. Compared to NTSC, PAL and SECAM have better resolution but lower refresh rates and hence more flicker. Sta...
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This document was uploaded on 04/07/2014.

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