The introduction of the compact disc, or CD, was the beginning of a ‘digital revolution’ which now dominates electronic media.
The introduction of the compact disc, or CD, was the beginning of a ‘digital revolution’ which now dominates electronic media.
Introduced in 1982, the CD was slow to catch on.
The sound was crisp and clear and the discs did not scratch as easily as vinyl records.
But people had to buy new machines to play them – and were reluctant to replace their record collections.
Despite the slow start, people did start buying the discs and their players, especially when prices began to fall and major stars began to release albums on the new media.
By 1988, sales of (digital) CDs had outstripped sales of (analogue) records.
Since then (digital) DVD has largely superseded (analogue) videocassette for delivering films.
The wavy groove of a record is a direct representation (an analogue) of sound waves.
In digital technology, sound waves are represented by a succession of binary numbers instead.
On the underside of a CD is a spiral track containing tiny indentations which represent the digits 0 and 1. This is scanned by a laser in the CD player and decoded into sound.
The quality of recorded sound on a CD is very high.
But something very close to CD quality can be recorded using far fewer binary digits per second – a smaller amount of digital information.
This led to the development of compressed audio formats, notably the ‘mp3’ (MPEG layer 3).
Images and video can also be ‘digitised’ – converted into a stream of binary digits.
The increasing popularity of the personal computer in the late 1980s and 1990s did much to encourage the uptake of digital technology.
As processing power increased, personal computers became able to manipulate the large numbers of binary digits required for computer-based ‘multimedia’.
Today, most people receive digital television signals; they speak on digital mobile telephones; they capture and share digital photographs and video; they listen to digital music on CD, on their computers or on mp3 players.
Whether they are carrying sound, text, images, video, or a combination of all four, all digital technologies are doing is manipulating streams of binary digits.