CD's History


A CD is 1.2 mm thick polycarbonate plastic disc weighs about 16 grams around the reflecting surface, a very thin layer of aluminium is on one side of the disc. A film of paint is applied to act as a protective shield. The label is on the other side with the usual offset printing as a background image or printing. The data are available on a CD in the form of a table tiny wells, called the indentation are in a spiral path. A well is located at 500 nm and 100 nm great depth and length varies from 850 to 3500 nm The areas between the two wells are considered areas.

The CDs are much more sustainable than the valuable memory audio formats. You can, however, a few factors damaged the environment and daily use. The data are much closer to the label, so that more damage occurs when the scratches are on the label. The logical format for storing audio data on a CD is a 2-channel 16-bit PCM-coded data at a rate of 44.1 kHz sampling frequency. The sampling rate has been directly elected, because the frequency of sampling theorem twice the frequency to the required records. With a little more calculations, the exact sampling rate of 44.1 kHz was decided.

A typical CD has a diameter of 12 cm and about 80 minutes of audio data can be stored on this. The small CD produced are also used for the storage of unique songs . They are 8 cm in diameter and can store, 24 minutes of audio data. The main research and development work has been done by Philips and Sony. One of the first CD are on the market the way back to the year 1982 and to this day remains one of the most popular multimedia audio recording.

In 1979, Phillips and Sony launched a joint working group to develop a successful digital audio CD. After a year's work "and many experiences and discussions, the CD was invented. No one can say that it has invented, a large group together invented the CD.

In August 1982, the first CD for commercial purposes has been manufactured in a factory of Philips in Germany. The first title, the music was on a CD was published "The Visitors" (1981) of ABBA. A short time later, in October of that same year, CD player, Sony has also reached the markets. The event is often referred to as the "Big Bang" in the field of digital audio.

The new concept was an immediate success on the market. Consumers were quite impressed by the quality of the audio CD. The price of the CD went very quickly, as the popularity increases in the proportions even more.

The CDs are in a number of variations. Some of them are the following:

CD-Text - CD allows for the storage of information as the name of the song, artist, the name of the album in the form of text with the standard audio data on the CD.

CD-Graphics - The more graphical data on the CD. They usually work on a normal CD player, but the production of graphical data to read a CD + G players.

CD-ROM - Read Only Memory ROM or, as the name says, for the CD drive, the data can not be read.

Video-CD - Video CD, VCD or CD with the video data.

Photo-CD - he was from Kodak for the storage of digital photos in a compact disc They were in a position to more than 100 images when the first start.

+ CD-RW - these are on the CD data can be written, erased and rewritten more than once.