How Cell Phones Work
Cell phones are very interesting! Have you ever wondered how a cell phone works? Well we have. Cell phones have changed a lot since 1984. The first cell phone that came out was called the Dyna TAC8000X. (top left) It weighed 2 pounds! The brick only offered a half-hour of talk time for every charge. You could get this amazing device for $3,994! The man who invented this phone is Ruby Knopp. (top left) He also invented the newer modern Motorola Razor. (top middle) Some of the new cell phones provide an incredible amount of functions, like: store contact information, make tasks or to-do lists, keep track of appointments and set reminders, use the built-in calculator for simple math, send and receive e-mails, internet, play games, watch TV, send and receive text messages, integrate other devices such as PDA's, MP3 players, and GPS receivers. One of the most interesting things about a cell phone is that it is actually a radio, an extremely sophisticated radio. The man who invented the telephone was Alexander Graham Bell (top right) in 1876. Wireless communication can trace its roots to the invention of the radio by Nikolai Telsa in the 1880s. When these two great technologies are combined it made the cell phone. People who needed mobile-communication devices had radio telephones in their cars. In the radio-telephone systems, there was one central antenna tower per city, and perhaps 25 channels available on the tower. In your car you needed a powerful transmitter. Not everyone could have a radio telephone because there were only 25 channels available per city. Each cell phone has a cellular system. A cellular system is a division of a city into small cells. Each cell has a base station that consists of a tower and a small building containing the radio equipment this allows widespread frequency reuse across a city, so that millions of people can use cell phones all at once. Each cell is typically sized at and covers about a 10 square miles...
Please join StudyMode to read the full document