9.2.1

Digital & Analogue Signals

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Analogue vs Digital Signals

Signals (things carrying information) can be either analogue or digital. An analogue signal can vary continuously between a maximum and a minimum value. A digital signal can only have set values, usually 0 or 1.

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Analogue

  • A dimmer switch on a light can give any brightness between on and off. Therefore it is an analogue signal.
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Digital

  • A normal light switch can only ever be on or off, nothing in between. Therefore it is a digital signal.

Benefits of Digital

There are many reasons why digital signals are better than analogue signals. These include:

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Reduce noise effects

  • In digital signals, noise (which makes the signal fuzzy) can change the 1s and 0s to slightly different values. For example a 1 could become a 0.97 or a 1.01.
  • It is easy to tell that a 1.01 or a 0.97 should be a 1, and that a 0.03 or a 0.12 should be a 0.
  • Therefore noise can be easily reduced for digital signals.
  • For analogue signals, we cannot tell what the original value was because a 0.97 could have been a 0.98, a 0.99, a 0.91 or any other nearby value.
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Cost

  • Digital communication systems are usually cheaper.
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Privacy

  • Data encryption means that only a certain person can receive the digital signal.
  • Analogue signals are easier to intercept.
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Computer compatibility

  • Digital information can be more easily processed by computers.
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Carry more information

  • Digital signals can carry more information per second than analogue signals.

Jump to other topics

1Physical Quantities & Units

2Measurement Techniques

3Kinematics

4Dynamics

5Gravitational Fields

6Deformation of Solids

7Thermal Physics

8Oscillations

9Communication

10Electric Fields

11Current Electricity

12Magnetic Fields

13Modern Physics

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