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eight to fourteen modulation (CD, DVD) (EFM)

Eight to Fourteen Modulation(EFM) is an encoding used on Compact Discs ( CD) and Digital Versatile Discs( DVD) that ensures higher storage density and flawless reading of the storage medium.

In the EFM process, 8 bits are converted into a bit pattern of 14 bits, with a minimum of three and a maximum of eleven zeros between the two ones. Fourteen bits are required for this concept, in which a byte with its 256 possible combinations is represented without two ones following each other.

Example of EFM encoding

Example of EFM encoding

The EFM method is implemented in CD drives. A variant of this method is EFM-Plus (EFM+), which is used in DVDs and uses 16-bit words and low frequency suppression for increased data security. EFM-Plus has 3 control bits per byte.

Englisch: eight to fourteen modulation (CD, DVD) - EFM
Updated at: 22.12.2011
#Words: 124
Links: encoding, call deflection (ETSI) (CD), digital versatile disc (DVD), storage density, medium
Translations: DE

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