Digital & Analogue Signals
Applied Science: BTEC Level 3 National Extended Diploma, topic 1.7.9
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.
Analogue
- A dimmer switch on a light can give any brightness between on and off. Therefore it is an analogue signal.
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:
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.
Cost
- Digital communication systems are usually cheaper.
Privacy
- Data encryption means that only a certain person can receive the digital signal.
- Analogue signals are easier to intercept.
Computer compatibility
- Digital information can be more easily processed by computers.
Carry more information
- Digital signals can carry more information per second than analogue signals.
Test yourself on Digital & Analogue Signals
Digital signals often only have which number of values?
Why is it easier to reduce noise from digital signals and not for analogue signals?
Which of these are true of digital and analogue signals?