Method and apparatus for performing DSV protection in an EFM/EFM+ encoding same
US6778104B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 8, 2002 |
| Grant date | Aug 17, 2004 |
| Priority date | — |
| Expiry date | Oct 8, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2020/1461
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An EFM/EFM+ encoding system is adapted to modulate a source symbol sequence into a modulated bit sequence that is further converted to a channel bit sequence, which is to be recorded on a recording medium and which has a cumulative Digital Sum Value (DSV), through NRZI conversion. An apparatus for performing DSV protection in the EFM/EFM+ encoding system includes a DSV calculation unit for calculating the DSV associated with the EFM/EFM+ modulated bit sequence, and a decision unit for adjusting at least a bit in the modulated bit sequence according to the result calculated by the DSV calculation unit such that the channel bit sequence from the NRZI conversion of the adjusted modulated bit sequence accumulates a relatively small DSV. A method of using the EFM/EFM+ encoding system to inhibit disc copying is also disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.