Digital cell phone from Nokia Millions of people in the United States and around the world use cellular phones. They are such great gadgets — with a cell phone, you can talk to anyone on the planet from just about anywhere! These days, cell phones provide an incredible array of functions, and new ones are being added at a breakneck pace. Depending on the cell-phone model, you can: Store contact information Make task or to-do lists Keep track of appointments and set reminders Use the built-in calculator for simple math Send or receive e-mail Get information (news, entertainment, stock quotes) from the Internet Play simple games Integrate other devices such as PDAs, MP 3 players and GPS receivers But have you ever wondered how a cell phone works? What makes it different from a regular phone? What do all those confusing terms like PCS, GSM, CDMA and TDMA mean? In this article, we will discuss the technology behind cell phones so that you can see how amazing they really are. If you are thinking about buying a cell phone, be sure to check out How Buying a Cell Phone Works to learn about everything you should know before making a purchase. Let’s start with the basics: In essence, a cell phone is a radio. One of the most interesting things about a cell phone is that it is actually a radio — an extremely sophisticated radio, but a radio nonetheless.
The telephone was invented by Alexander Graham Bell in 1876, and wireless communication can trace its roots to the invention of the radio by Nikolai Tesla in the 1880 s (formally presented in 1894 by a young Italian named Guglielmo Marconi).
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... other (Martin 15).Besides the dangerous of drivers talking on cell phone, cell phone radiation is also the cause for controversy. Like televisions, ... operating a motor vehicle-particularly when using a cell phone. Cell phone can be very harmful.When people are talking on the ... are many distractions occurring in the car, such us radio tuning, eating, conversing with other occupants, and applying make ...
It was only natural that these two great technologies would eventually be combined! In the dark ages before cell phones, people who really needed mobile-communications ability installed radio telephones in their cars. In the radio-telephone system, there was one central antenna tower per city, and perhaps 25 channels available on that tower. This central antenna meant that the phone in your car needed a powerful transmitter — big enough to transmit 40 or 50 miles (about 70 km).
It also meant that not many people could use radio telephones — there just were not enough channels. The genius of the cellular system is the division of a city into small cells. This allows extensive frequency reuse across a city, so that millions of people can use cell phones simultaneously. In the next section, we ” ll look closer at these cells.
In a typical analog cell-phone system in the United States, the cell-phone carrier receives about 800 frequencies to use across the city. The carrier chops up the city into cells. Each cell is typically sized at about 10 square miles (26 square kilometers).
Cells are normally thought of as hexagons on a big hexagonal grid Each cell has a base station that consists of a tower and a small building containing the radio equipment (more on base stations later)..
