A microphone makes a smooth, ever changing voltage. A computer prefers a stream of ones and zeros. Both pick up noise as they travel, but only one of them can be cleaned up perfectly at the far end.
An analogue signal varies continuously and can take any value, while a digital signal is only highs and lows, ones and zeros. Because each part of a digital signal is read as a 1 or a 0 at a threshold, the noise it picks up can be stripped off and a clean copy regenerated, which analogue cannot match.
An analogue signal varies continuously and can take any value; a digital signal is a series of discrete highs and lows, ones and zeros. The benefit of digital is that the signal can be regenerated, removing the noise added along the way.
Both types pick up noise. Only a digital signal can be regenerated free of it.
Turn up the noise and watch the analogue trace get permanently messy while the digital one is cleaned at the threshold and rebuilt.
Four quick checks. Each correct answer earns XP and lights this skill on your star map.
An analogue signal is one that...
A digital signal is made up of...
The main benefit of sending information as a digital signal is that it can be...
Which type of signal can be cleaned of noise and rebuilt exactly?
Both signals collect noise, but a digital signal can be regenerated, so it stays accurate over long distances.
| Analogue signal | Digital signal |
|---|---|
| Varies smoothly and can take any value | Only two levels, 1 or 0 |
| Noise blends in and cannot be fully removed | Read at a threshold, so noise is removed and the signal regenerated |
| Quality degrades over long distances | Stays accurate, the clean signal is rebuilt at each stage |
Both analogue and digital signals pick up noise as they travel. The advantage of digital is not that it avoids noise, but that, being only highs and lows, it can be regenerated cleanly at a threshold. Analogue noise blends into the signal and cannot be fully removed.
Unlocks once the four checks above are done. Worth more XP, written in the style of Paper 2.
Over a long cable both signals gain noise. A digital signal still arrives accurately because it can be...
Which is an example of an analogue signal?
Why can analogue noise not be fully removed at the far end?
Digital and analogue complete the EM strand. Keep the chain going.