Audio cd

The CD design was proposed after the commercial failure of Philips video disc technology in 1978 . The video disc was one of the first commercial products to take advantage of laser technology, which made it possible to read from a disk without mechanical contact.

Research began back in 1969 and inspired the Italian Antonio Rubbiani, who demonstrated a prototype video disc system 12 years before it hit the market.

In 1970, Philips began working on an audio disc system called the ALP ( English audio long play ), which competes with the record but uses laser technology. Philips Technical Director Lou Ottens was the first to propose that the ALP system should be physically smaller than a long-playing record and accommodate up to 1 hour of sound material.

At an early stage of the project, the idea of ​​recording a quadraphonic sound was worked out, but in this case a disc with hourly recording turned out to be 20 cm in diameter, and they refused it.

In 1977, Philips began developing the new audio format more seriously. The name of the product was discussed, options such as Mini Rack, MiniDisc and Compact Rack were considered. The team agreed on the name "CD" because of the assumption that this would remind customers of the success of the CD .

In March 1979, Philips held a press conference where it introduced the sound quality of the CD, as well as to impress its competitors. A week later, an agreement was reached in Japan with Sony to create a standard for a CD.

Philips plans to produce 11.5 cm diameter discs were changed by Sony, which insisted that the disc should fully accommodate Beethoven’s 9th symphony. ^{[1] The} duration of the symphony was 74 minutes, so the disk size was increased to 12 cm.

In 1980, Philips and Sony released the Red Book standard, which later became the standard for CDs. In the future, companies separately worked on devices for playing CDs.

In April 1982, Philips introduced its first CD player.

The first commercial discs were ABBA's The Visitors and Richard Strauss Alpine Symphony , recorded by conductor Herbert von Karayan .

In 1985, Dire Straits' Brothers In Arms became the first album sold in a million copies.

In 1988, the USSR adopted two standards that describe compact discs - GOST 27667-88 “Digital sound system“ Compact disc ”. Parameters ”and GOST 28376-89“ CD. Parameters and sizes. "

In 2000, world CD album sales peaked at around 2.455 billion. In 2006, that figure dropped to 1.755 billion.

In 2015, the American Recording Industry Association (RIAA) published a report ^[2] , which indicated that the number of sales of physical media (CD) amounted to 124.5 million copies.

The name Red Book (Red Book) is associated with the introduction of the standard in a set of standards for CD formats, known as Rainbow Books ("Rainbow books"). The first edition of the standard was published in June 1980 by Philips and Sony , then finalized by the Digital Audio Disc Committee and ratified as IEC 908. The standard is not freely available and must be licensed by Philips; license cost is 5,000 US dollars. The text of the standard is available for download in PDF format and costs $ 242.

CDDA should not be confused with a CD-ROM , although they use a similar physical medium and one channel coding system, i.e. in some players it is possible to play CD-ROM discs in the same way as CD-DA, but without sound and usually with 1 track. And if you put a VCD- drive, then the number of video tracks will be displayed on the player’s display, but there will still be no playback.

• The maximum time for all recordings is 79.8 minutes ^[3]
• Minimum audio track time is 4 seconds (including a 2 second pause)
• Maximum number of audio tracks - 99
• Maximum number of reference points (sections of audio tracks) - 99 without time limits
• Must attend International Standard Recording Code (ISRC)

• Disc diameter - 120 mm
• The diameter of the inner hole - 15 mm
• Disc thickness - 1.2 mm
• Material - polycarbonate or polyurethane
• Information playback - constant linear speed 1.2-1.4 m / s
• Track pitch - 1.6 ± 0.001 μm
• Pit width - 0.4 μm
• Pit Depth - 0.12 μm
• Pit length - 0.83-3.1 microns
• Laser wavelength - 780 nm
• 0.45 Numeric Reading Aperture
• Sampling Rate - 44.1 kHz
• Bit depth - 16 bits (linear quantization)
• Reading speed of audio information - 1.4112 Mb / s
• The general speed of reading information - 1,9404 Mbit / s
• Channel read speed - 4.3218 Mbps
• Channel Modulation - EFM (Conversion 8-14)
• Error Correction - Reed-Solomon Interleaved Double Correction Code (CIRC), as well as replacing uncorrected errors using interpolation .
• Redundancy - 25%
• Maximum recording time - 74 (99.9999%) min
• The maximum amount of information recorded on the disk - 0.78 GB

• Nikamin V. A. Digital sound recording. Technology and standards. - SPb. : Science and Technology, 2002. - 256 p.
• Radio Magazine, No. 11, 1987, pp. 17 - 20. (The structural diagram of the CD player is considered, and the principles underlying the recording-playback of the CD are described).
• GOST 27667-88 “Digital sound system“ Compact disc ”. Options"
• GOST 28376-89 "CD. Parameters and sizes »

• How the CD was developed . news.bbc.co.uk (August 17, 2007). Date of treatment October 30, 2011. Archived February 18, 2012.