In I/GCSE Physics, we will learn about electromagnetic waves used in communications (Part 2).
Signal
This coded information can be carried by switching the electromagnetic carrier wave off and on to create short burst of waves (pulses) where ‘0’ = no pulse and ‘1’ = pulse. When the waves are received, the pulses are decoded to produce a copy of the original sound wave or image.
When it comes to I/GCSE Physics, both DIGITAL and ANALOGUE signals become weaker (their amplitude becomes smaller) as they travel – the transmitted signals therefore have to be AMPLIFIED at selected intervals to make them stronger.
During transmission the signals can also pick up random variations, called NOISE, which reduces the quality of the signal.
Analogue
In I/GCSE Physics, analogue signals have many different values so it is hard to distinguish between noise and original signal.
This means that noise cannot be completely removed and when the signal is amplified, any noise that has been picked up is also amplified.
Digital
Digital signals, which have two states, on (1) or off (0), can still, be recognised despite any noise that is picked up. Therefore it is easy to remove the noise and clean up the signal, restoring the on/off pattern This means when it is amplified, the quality of the digital signal is retained |
Another advantage of using a digital signal is that the information can be stored and processed by computers. Generally the more information stored or the more bytes, B (image/sound is measured in) the higher the quality of the sound or image.
That's all~ Thanks for watching.
