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  3. The basic concept of cellular phones began in 1947, when researchers looked at c

The basic concept of cellular phones began in 1947, when researchers looked at c

游客2025-02-21  12
问题 The basic concept of cellular phones began in 1947, when researchers looked at crude mobile(i.e. police car)phones and realized that, by using small cells, or ranges of service areas, with frequency reuse, they could increase the traffic capacity of mobile phones substantially. However, at that time, the technology to accomplish this was nonexistent. Dr. Martin Cooper, a former general manager for the systems division at Motorola, is considered the inventor of the first modern portable handset. Cooper made the first call on a portable cell phone in April 1973. He made the call to his rival, Joel Engel, Bell Laboratories head of research. Bell Laboratories had introduced the idea of cellular communications back in 1947. However, Motorola was the first to incorporate the technology into a portable device that was designed for use outside of an automobile. [br] Which of the following can be inferred from the passage regarding mid-twentieth century police car technology?
选项 A、Mid-twentieth century police car technology had no influence on the development of truly portable telephones.
B、Mid-twentieth century police car technology was hailed as a revolutionary development.
C、Mid-twentieth century police car technology was considered by many politicians to be crucial to America’s war against communism.
D、Mid-twentieth century police car technology was not completely understood by Bell Laboratories.
E、Mid-twentieth century police car technology allowed officers a degree of mobility in communication not available to the general public.
答案 E
解析 The best answer is E. According to the passage, early mobile phones were found in police cars. Portable phones were not available for another 25 years, which is after the timeframe of the question.
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