Eight-to-Fourteen Modulation (EFM)

Definition - What does Eight-to-Fourteen Modulation (EFM) mean?

Eight-to-fourteen modulation (EFM) is a data encoding technique invented by Kees A. Schouhamer Immink, which makes CDs and Hi-MD MiniDiscs highly resilient to dust, fingerprints and tiny scratches. Prior to the creation of this data encoding technique, these imperfections negatively affected retrieved data.

Techopedia explains Eight-to-Fourteen Modulation (EFM)

Eight-to-fourteen modulation modifies binary code data and allows 17 bits of data space to be used to encode 8 bits of data. The 8-bit block of data is replaced by a 14-bit codeword using a lookup table. This requires more space for data, but assures that imperfections and foreign material do not cause critical data to be missed by the optical pickup in the playback mechanism. This involves two extra zeros placed between two consecutive ones (Ten consecutive zeros are the maximum allowed between consecutive zeros.) Consistently applied, the data can be read accurately even with the disc imperfections and foreign material present. For DVDs and SACDs, a channel code called EFMPlus is used, which translates 8-bit words into 16-bit code words. This results in a 6.25 percent increase in storage capacity above that achieved by classic EFM.

Share this:

Connect with us

Email Newsletter

Join thousands of others with our weekly newsletter

The 4th Era of IT Infrastructure: Superconverged Systems
The 4th Era of IT Infrastructure: Superconverged Systems:
Learn the benefits and limitations of the 3 generations of IT infrastructure – siloed, converged and hyperconverged – and discover how the 4th...
Approaches and Benefits of Network Virtualization
Approaches and Benefits of Network Virtualization:
Businesses today aspire to achieve a software-defined datacenter (SDDC) to enhance business agility and reduce operational complexity. However, the...
Free E-Book: Public Cloud Guide
Free E-Book: Public Cloud Guide:
This white paper is for leaders of Operations, Engineering, or Infrastructure teams who are creating or executing an IT roadmap.
Free Tool: Virtual Health Monitor
Free Tool: Virtual Health Monitor:
Virtual Health Monitor is a free virtualization monitoring and reporting tool for VMware, Hyper-V, RHEV, and XenServer environments.
Free 30 Day Trial – Turbonomic
Free 30 Day Trial – Turbonomic:
Turbonomic delivers an autonomic platform where virtual and cloud environments self-manage in real-time to assure application performance.