THE TV for: Maria Antonia rivera Juanita aristizabal Sara rodas quinchia

CONTENTS problems and solutions History Evolution Images Conclusions Glossary bibliography

PROBLEMS Critical areas In the representation of an image The representation of an image in any of the technologies used for the screen of the televisions and monitors has four critical areas for to save where the obtained results are relevant for the final successful quality. You are areas are: Reproduction of blacks of last generation before of those of color The difficulty of the reproduction of the real black is one of the areas most compromised in the representation of an image on a screen of television. The low levels of luminance that generate the blacks, or gray very dark, are difficult to obtain due to the utilization of retroiluminación or levels of fattening of the plasmas. The dark areas of the represented images lack range in the blacks, remaining these annulled (turned in gray) distinction between a few levels and others, giving place to artifices and noise. The TRC have a minimal level of excitation of the luninofosforos that they provide an acceptable black. The same thing does not happen in the plasmas and less still on the LCD screens that they need retroiluminación what does that it is not achieved to never have the dark screen. The technology SMELL, to the being every pixel an individual issuer, it can reproduce a very royal range of black, since to be achieved the issuer to extinguish totally

Reproduction of the color in low levels of light The reproduction of the color in images with areas of few luminance is one of the most difficult points for the reproduction of an image. In TV's system the color arises from the mixture of three lights corresponding to three different colors (called " primary colors ": Red, Green and Blue) the scanty levels of luminance do that this mixture could not be correct on having fallen down in the not linear zones of the issuers of light. Width of the dynamic range In order that an image could turns clear and clear there must be able to be reproduced all the levels of light contained in the same one. Levels of light that in the mixture of three basic colors give the whole range of colors that must be represented. From the subdued absolute one that provides a royal black to us up to the ignition to full sheen for a white, we have the whole range of levels to reproduce. The linearity, very critical in the ends, of the elements that the different technologies use for the representation of the image is the one that gives body to the dynamic range. The cathode-ray tubes support a typical, called curve ganma, that it were necessary to to compensate (it is done in the issuer) to achieve a linear ideal response. The systems of plasma and LCD have a not linear response and with a relation of very poor contrast what does that if dynamic width is small. The technology SMELL it achieves a good result.

Rapid time of response The television is a system of transmission of images in movement. The time of response of the screens of reproduction of the images is fundamental for the loyalty of the reproduced. The rapid changes in the images must be realized in such a way that they do not suppose delays and distortions or loss of resolution. For it the times of persistence and of histéresis of the generating elements of the image they are the most important. The times of activation and deactivation of the light elements are fundamental for a correct representation of the image in movement. These times not only depend on the technology of the screen but also on the accused of the sign. The concept of time of change between two levels of gray, in English herd - to-grey switching speed, is the one that determines this parameter.

Solutions High place contained of motivation: On having combined Images, text, animations, it is more attractive for his recipient and therefore major stimulus has that with other means. He contributes to the development of the aptitude to listen, observing and relating Provides a correct base for the development of the conceptual thought and facilitates the comprehension of a topic especially Can be in use as educational resource Is a didactic resource The television offers all the visual alternatives, of sound, movement, color and special effects that you could pay. It is a powerful way with a great visual impact. Across her we can find out about relevant aspects that they happen in the mundoEn 1929 the BBC he assured a regular service of transmission of images with certain reluctance, due to the fact that it did not see in the new invention any practical usefulness. The different studies realized in order to develop the TV in colors, it was returning to put in check the compatibility that the public was needing of the devices. The economic interests of the big companies pressed strongly in order that there was adopted a system of not compatible color to all the devices. Though, certainly it was the great quantity of televisions sold in those days, the fact motivated the agreement to develop a TV fullly compatible color. Another problem was that a sign in color saw in a TV in black and white and vice versa. Ultimately this was corrected, adopting from 1953 the name of regulatory committee known as system NTSC.

HISTORY n 1881, with the invention of Paul Nipkow disk Nipkow, the first breakthrough is made to make television a relevant communication medium. The change would bring television as we know it today was the invention of Philo Taylor Farnsworth iconoscopio of and Vladimir K. Zworykin. This would lead to the fully electronic television, which provided for greater image definition and self-illumination. The first public television broadcasts the BBC made in England in 1927 and the CBS and NBC in the United States in In both cases mechanical systems were used and the programs are not issued on a regular schedule. The emissions program began in England in 1936, in the Soviet Union on March 8, 1938 and in the United States on April 30, 1939, coinciding with the opening of the World Expo in New York. Scheduled broadcasts were interrupted during World War II and resumed when the war ended.

EVOLUTION

As the years passed, the screens are still small, but the size of the box was increasingly compact so they can be put on a table or on the legs of a person. At the end of the 30s until the end of World War II, Andrea 1F5 model went on sale. During these years, television was perfected since its mechanism became fully electric. This allowed several countries begin broadcasting local programming. HOWEVER, after the war ended, the television production under a lot and some stopped their transmission channels In 1948, after World War II, he was released model 19A111 Admiral. Because the economy recovered and people began to move their money, television became a household that everyone wanted to buy. In the 50 he was released on RCA model 21. This model was a significant change as was much like TVs that exist today. In 1960 television gave a radical shift from the transmission in black and white to color transmission.

In 1974 he was released the Zenith model. This model is quite famous for its distinctive '70s look. In the '80s television it began to look like the model we know today. A revolutionary change was the remote control, although it was very expensive, it became an important complement to television many homes. In the 90 projection televisions they began to be sold. This created a need for larger screens imitating the experience of "your home theater.“ Today TVs are becoming more innovative. Plasmas, LDC screens and high definition are lighter every day and so thin they can be hung on the wall like a painting over the house.

CONCLUSIONS television is a mass medium, in which not only serves as a source of knowledge, research, but also as a means of both family and staff entretencion.

GLOSSARY The low levels The TRC The technology SMELL the issuer LCD SMELL the BBC

BIBLIOGRAPHY Wikipedia Yahoo The google images