作业帮用英语介绍手机是怎么通信的
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用英语介绍手机是怎么通信的
用英语介绍手机是怎么通信的
用英语介绍手机是怎么通信的
How do mobile phones work?
Imagine calling a friend on the other side of town.As you chat away,your phone converts your voice into an electrical signal,which is then transmitted as radio waves and converted back into sound by your friend’s phone.A basic mobile phone is therefore little more than a combined radio transmitter and a radio receiver,quite similar to a walkie-talkie or CB radio.
In order to remain portable,mobile phones need to have relatively compact antennas and use a small amount of power.This means that mobile phones can send a signal over only a very short range,just like a walkie-talkie.
The cellular network,however,enables you to spread the latest gossip regardless of how far away your friends are.This is done by dividing up land into a patchwork of ‘cells’ – hexagonal areas of land each equipped with their own phone mast (also called a base station).
These huge phone masts pick up the weak signal from your phone and relay it onwards to another phone mast nearer to your friend.And if you’re on the move while you talk,your phone switches masts as you go without interrupting your call.