In this topic we are learning to: z Discuss the differences between analogue and digital signals. z Describe how processors can store and transfer information. z Explore the impact of modern technologies on our daily lives.
We live in the information age. This means that we access a large amount of digital information.
Mobile phones and the internet have become part of our daily lives. These tools allow us, at the touch of a button or screen, to speak face-to- face with a person in Australia quicker than we could call to a neighbour’s house. Astronauts, such as former International Space Station commander Chris Hadfield, can even send tweets to Earth from outer space.
My modern life
Spend a day without using your mobile phone or the internet and write a diary entry about the experience.
Analogue to Digital What happens when you make a phone call?
When you speak into the phone, a microphone detects the vibrations of the sound waves from your voice. Using a coil of wire and a magnet, these vibrations are converted into an electrical signal. This is known as an analogue signal.
An analogue signal is a signal that has varying values.
When an analogue signal is transmitted to a computer processor (such as those in a phone or laptop), it is converted into a digital signal.
A digital signal has two values only, 1 or 0.
Digital signals have two main advantages over analogue signals:
1. They can carry more information per second.
2. They have better quality over distances.
Fig. 20.1.2 Analogue and digital signals
1 0 1 Digital
Only two types of signal
0 1 0 1 0 349 349 Analogue
Full range of varying signals
Fig. 20.1.1
One of Chris Hadfield’s tweets from space: ‘Don’t tell my crew, but I brought them Easter eggs :)’
20.1 Key Words
Information age Analogue Digital Binary Bit
Byte
Electromagnetic spectrum Radio waves Microwaves World Wide Web
