Dynamic information storage or retrieval – Condition indicating – monitoring – or testing – Including radiation storage or retrieval
Reexamination Certificate
2005-01-04
2005-01-04
Huber, Paul W. (Department: 2653)
Dynamic information storage or retrieval
Condition indicating, monitoring, or testing
Including radiation storage or retrieval
C369S053120, C369S124070, C369S275300
Reexamination Certificate
active
06839312
ABSTRACT:
The ability of a data reader, such as a CD-ROM drive, to access, extract, or otherwise read the data on a digital audio compact disc provides a problem for the music industry. A user can use his CD-ROM drive to read the data from an audio disc into a computer file, and then that data can be copied. To provide copy protection, errors are deliberately introduced into the data on a CD, but these errors are of a type which are generally transparent to an audio player but which will interfere with the reading of the audio data by a data reader. According to the standards, the data on a CD is encoded into frames by EFM (eight to fourteen modulation). Each frame has sync data, sub-code bits providing control and display symbols, data bits and parity bits, and includes 24 bytes of data, which is audio data for a CD-DA. The standard requires that 98 such frames are grouped into a sector. To provide copy protection, each is provided with a non-standard number of frames, for example, has 99 rather than 98 frames. Then the S0and S1sub-code synchronisation patterns are placed one frame later than they otherwise would be, but the data within each frame remains the same. An audio player would divide the 24 bytes of data from each frame of the sector into 4 byte samples and continue playing the disc, albeit with an inaccurate time display. However, a data reader used to read audio data from the CD-DA to enable a copy to be made, would produce a copy having a degraded quality of sound.
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Patent Abstracts of Japan vol. 011No 328 (p629), Oct. 27, 1987 6&JP 62 111321A(Onken:KK May 22, 1997Patent Abstracts of Japan vol. 010 No 072 (p-438), Mar. 22, 1996&JP 60 211534 A(Tokyo Denki KK Oct. 23, 1995.
Edward Roger
Heylen Richard A A
Huber Paul W.
Macrovision Corporation
Salter Jim H.
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