Turning music into digital data has the same benefits as in other areas - digital data allows high quality in little space - but how do you turn a constantly altering quantity like a soundwave into numbers?
This process is called "analogue to digital conversion", or A/D conversion. The first stage is "sample and hold". This takes a sample of the wave and holds its level just long enough for it to be measured. This results in the stepped wave, shown in green above.
The second stage is to measure the level of each step. This provides a series of numbers which represent the original wave. These numbers are the digital data which are recorded on a CD, Minidisc or in an MP3 file.
