Optical disk with wobbled tracks and apparatus using this optical disc

Abstract

Address information is formed by M wobbles (integer M is the number of wobble waves) per bit as a basic unit, and is NRZ-recorded. Also, a sync signal used in sync detection of the address information is formed by N wobbles per bit as a basic unit (integer N is the number of wobble waves and M=2N). The sync signal with such configuration (6 wobbles per bit) is recorded on the head side of the address information (12 wobbles per bit). In this way, even when external noise is large, a modulated wobble signal can be demodulated more accurately.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2003-015019, filed Jan. 23, 2003, the entire contents of which are incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to an optical disc having wobbled tracks, and an apparatus (recording / reproduction apparatus, mastering apparatus, or the like) or method using this optical disc. [0004] 2. Description of the Related Art [0005] As is well known, in recent years, optical discs having a single-layer / single-sided size of 4.7 GB are commercially available as those which can achieve high-density recording of information. For example, a DVD-ROM is available as a read-only optical disc, and a DVD-RAM, DVD-RW, DVD+RW, and the like are available as rewritable discs. Also, a DVD-R is available as a “write-once” optical disc. [0006] On these optical discs, a...

AI Technical Summary

Benefits of technology

"The present invention relates to a method for recording address information and sync signals on an optical disc. The method uses M wobbles (where M is the number of wobble waves) per bit as a basic unit for forming the address information, and NRZ-records it. The address information includes the address itself, error detection or collection codes, and address information transformed with modulation table or gray-code rules. The optical disc records the address information using this method. The sync signal is formed by N wobbles per bit as a basic unit (where N is the number of wobble waves, and M=2N). The optical disc records the sync signal on the head side of the address information. The invention reduces the number of times of phase inversion during demodulation of the wobble-modulated address information or sync signal, making it more accurate even in the presence of external noise. This results in a more reliable detection of the physical address on the optical disc, even at increased recording density. The invention also reduces detection errors of the sync signal / address information, improving the accuracy of the optical disc."

Problems solved by technology

When such modulation method is used, if external noise increases due to track pitch narrowing, demodulation errors are more likely to occur.

Images