Television

4467 Words Sep 23rd, 2014 18 Pages
I did this to make an account Television is a telecommunication medium that is used for transmitting and receiving moving images and sound. Television can transmit images that are monochrome, in color, or in three dimensions. The word television comes . Television may also refer specifically to a television set, television program, or television transmission.
First commercially available in very crude form on an experimental basis in the late 1920s, then popularized in greatly improved form shortly after World War II, the television set has become commonplace in homes, businesses, and institutions, particularly as a vehicle for entertainment, advertising, and news. During the 1950s, television became the primary medium for molding
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The holes were spaced at equal angular intervals such that, in a single rotation, the disk would allow light to pass through each hole and onto a light-sensitive selenium sensor which produced the electrical pulses. As an image was focused on the rotating disk, each hole captured a horizontal "slice" of the entire image.
Nipkow's design was not practical until advances in amplifier tube technology became available. Later designs used a rotating mirror-drum scanner to capture the image and a cathode ray tube as a display device, but moving images were still not possible due to the poor sensitivity of the selenium sensors. In 1907, Russian scientist Boris Rosing became the first inventor to use a CRT in the receiver of an experimental television system. He used mirror-drum scanning to transmit simple geometric shapes to the CRT.
Using a Nipkow disk, Scottish inventor John Logie Baird successfully demonstrated the transmission of moving silhouette images in London in 1925 and of moving, monochromatic images in 1926. Baird's scanning disk produced an image of 30 lines resolution, just enough to discern a human face, from a double spiral of lenses. This demonstration by Baird is generally agreed to be the world's first true demonstration of TV, albeit a mechanical form no longer in use. Remarkably, in 1927, Baird also invented the world's first video recording system, "Phonovision;" because the signal
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