【文章內(nèi)容簡介】 ly in a series of steps. In 1922, 21yearold Philo Farnsworth, allegedly by pondering the rows in the plowed fields of his native Idaho, came up with the idea of an “image dissector”, scanning an image in a series of lines. Working with a group of engineers, Vladimir Zworykin invented the iconoscope tube in 1923. Both of these pioneers had e up with the essential technology for a television camera—an electronic scanning system. Another independent inventor, Allen Dumont, had developed the essential technology for a receiver picture tube. Also crucial in television’s development were Guglielmo Marconi and Lee de Forest. Marconi eliminated sound’s dependence on wires and put sound on airwaves. De Forest contributed the Audion tube, which amplified radio waves so that people could hear the sound clearly. Based on the technologies mentioned above, television arrived on the scene in the late 1940s and became a household staple faster than any other home appliance had done previously. Take the USA as an example. In 1950, only 9 percent of . homes owned television sets. However, by 1960, almost 90% of American households had television sets. The number of TVs in the last three decades has been increasing at a surprising speed. It is estimated that there are about 800 million television sets in use worldwide, making television a central part of people’s life. The development of TV newsThe word “television”, which once meant programs delivered by antennas through overtheair signals, now means a television screen, where a variety of delivery systems bring viewers a diversity of programs. Although TV has been blamed for everything from declines in literacy to rises in violent crime, every once in a while it is praised, too, for giving viewers instant access to world events and uniting audiences in times of national crisis. Television can bring its viewers to a gallery they might never visit, or to a baseball game they cannot attend or closer to the solar system than they could see through a telescope. The technology of television, adding pictures to the sounds of radio, has verily transformed people’s living and learning patterns. Even the biggest best sellers reach only a fraction of the audience that will watch a similar program on television. For instance, it took 40 years for Gone With the Wind to sell 21 million copies. However, 55 million people watched the first half of the movie on television in a single evening! During the 1930s, several panies around the world were actively preparing to introduce television to the public. As early as 1935, the BBC initiated experimental television broadcasts in London for several hours each day. Since TV adds instant images to the coverage of events, TV broadcasting soon enjoyed popularity. Ever since its invention in the late 1940s, television has quickly taken over radio and newspaper in news transmission. In 1949, the year began with radio drawing 81 percent of all broadcast audiences. By the year’s end, television had grabbed 41 percent of the broadcast market. When the audiences began experiencing the thrill of actually seeing as well as hearing events as they occurred, the superiority of television was established beyond doubt. Besides, television can deliver the news to a larger audience faster than any other media. It then bees the focus for people to acquire news. For many people, someone or something that does not appear on television does not fully exist in the social sense. The Watergate scandal became “real” not when the Washington Post reported the stories but when work television news reported that the Washington Post reported the stories. Similarly, civil rights and antiVietnam War protests became social realities not when demonstrators took to the streets but when the protests were viewed on television. The categories of TV newsIn order to cater for the needs of the audiences, different categories of news are explored and presented on the TV screen. TV programs share great resemblance with other media. They include world news, regional news, local news, sports news, weather news, entertainment news, business news, and news programs from around the world. However, there are several types of news programs which are unique to the television, the length of which varies from 2minute headline summaries to 24 hours of nonstop news. They include bulletin, news program, documentary, and 24hour news. BulletinThe bulletin is a snapshot of the day’s news at a point in time and is usually on air from three to five minutes. Individual items are kept deliberately short – at around 30 seconds – so a good number of stories can be packed in. TV bulletins are illustrated with video clips and stills. Only shorter headline summaries are usually read straight through without illustration. News programA news program aims to provide a broader view of the day’s news, summarizing the best stories of the day instead of the hour. Its length usually ranges from 20 to 60 minutes. Items are generally longer and more detailed than those in a bulletin and have more sophisticated stills and graphics. Some shorter stories may also be incorporated to increase the breadth of coverage. If a program is to gain audience loyalty, it will have to establish a clear identity and have a greater balance and variety of material than a bulletin. DocumentaryThe documentary deals with a topical issue or subject in greater depth. Some immediate and newsworthy occurrences should have taken place before the topical subject is aired. Documentaries usually last between 20 minutes and an hour and will cover a single theme or a small number of issues. Documentary styles vary from straightforward reportage to dramatized documentary. Events and conversations are reconstructed in the dr