 funny angle. (It's that big silver cylin- der you see when you open the slot where the tape is inserted.) By 1956, Sarnoff and Ampex had created a commercially viable product. They demonstrated the Mark IV to 200 CBS affiliate managers in April of that year. When David Sarnoff walked out on the stage and stood next to his own prerecorded image playing on the television next to him, the room went berserk. In 4 days, Ampex took $5 million in video machine orders. Modern Video Technology Today's palm-size videotape recorders are a far cry from the washer- dryer-size Mark IV of 1956. But physical dimensions are only a piece of the video story. The first video systems were analog and relied on a technique called composite video. In composite video, all of the signal components-such as color, brightness, audio, and so on-are combined into a single multi- plexed signal. Because of the interleaved nature of this technique, a com- posite signal is not particularly good and suffers from such impairments as clarity loss between generations (in much the same way an analog audio signal suffers over distance) and color bleeding. Unfortunately, bandwidth at the time was extremely expensive and the cost to transport five distinct high-bandwidth channels was inordinately high. Composite video, therefore, was a reasonable alternative. As the cost of bandwidth dropped in concert with advances in trans- mission technology, component video emerged, in which the signal com- ponents are transported separately, each in its own channel. This eliminated many of the impairments that plagued composite systems. Several distinct component formats have emerged including RGB, YUV (for luminance [Y], hue [U], and saturation [V]), YIQ, and a number of others. An interesting aside: Luminance is analogous to the brightness of the video signal, whereas hue and saturation make up the chromi- nance (color) component. Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companie