Dynamic information storage or retrieval – Condition indicating – monitoring – or testing – Including radiation storage or retrieval
Reexamination Certificate
2000-06-01
2004-01-06
Young, W. R. (Department: 2653)
Dynamic information storage or retrieval
Condition indicating, monitoring, or testing
Including radiation storage or retrieval
C369S047480
Reexamination Certificate
active
06674705
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to storing data on optical disks. In particular, it relates to detecting digital data written on a clock reference structure formed on a servo track.
BACKGROUND OF THE INVENTION
Some optical disk standards have a permanent clock reference structure formed continuously along servo tracks. This clock reference structure provides a clock reference signal that is generated by an optical transducer as the clock reference structure passes by the optical transducer as the optical disk rotates. One such optical disk standard is called DVD+RW. DVD+RW is specified by the European Computer Manufacturers Association (ECMA) in several standards and draft standards. Many of these standards and draft standards are available at http://www.ecma.ch or by ordering them from ECMA, 114 Rue du Rhône, CH-1024 Geneva, Switzerland. One such draft standard is titles “120 mm ReWriteable DVD (DVD+RW) Capcity: 4,7 Gbytes and 9,4 Gbytes” dated February 1999 which is hereby incorporated herein by reference.
This draft standard specifies that the rewriteable area contain a phase modulated deviation from the nominal centreline called wobble. This wobble provides a permanent clock reference structure and also contains addressing information called Address-in-Pregroove or ADIP. The ADIP data is placed on the track using bi-phase shift keying (BPSK). In other words, a “0” is represented on the disk by a wobble with a first phase angle and a “1” is represented on the disk by a wobble that is 180° different from that first phase angle. The transitions between these two phases are called wobble inversions.
Accordingly, there is a need in the art for a means of detecting wobble inversions. This means should have good noise immunity and not be sensitive to low frequency shifts of the wobble signal. This means should also be inexpensive to produce and require as little circuitry as possible.
SUMMARY OF THE INVENTION
In a preferred embodiment, the invention utilizes a tuned circuit that filters out noise and also generates a transient at the point the wobble inversion occurs. This transient can be cleanly detected to determine the presence of a wobble inversion. The invention is easily tuned to accommodate different wobble frequencies and is well adapted to inexpensive fabrication. The present invention may be implemented as a bandpass tuned circuit whose output is fed to a high-gain saturating amplifier. When a wobble inversion occurs, the output of the saturating high-gain amplifier reacts with a half-cycle that has an increased duration as compared to half-cycles without wobble inversions. The increased duration of this half-cycle can be detected.
REFERENCES:
patent: 4807214 (1989-02-01), Getreuer
patent: 5315567 (1994-05-01), Fuji et al.
patent: 5377178 (1994-12-01), Saito et al.
patent: 5852599 (1998-12-01), Fuji
patent: 5862123 (1999-01-01), Horie et al.
patent: 5933411 (1999-08-01), Inui et al.
patent: 5953297 (1999-09-01), Maeda et al.
patent: 6046968 (2000-04-01), Abramovitch et al.
patent: 6192009 (2001-02-01), Kim
patent: 6219331 (2001-04-01), Miyamoto et al.
“4.7 GByte Re-Writable Disc System Based On DVD-R System,” Masayoshi Yoshida, Yoshitaka Shimoda, Hidehiro Ishii, Akiyoshi Inoue. AV&Recording Development Center, Research & Development Group, Pioneer Corporation. IEEE Transactions on Consumer Electronics, vol. 45, No. 4, Nov. 1999. Pp. 1270-1276.
“Examination of the Read/write Characteristics of an MO Signal with a Wobbled Groove Clock,” Hiroshi Watanabe, Kenji Asano, Noboru Mamiya, Yoshihisa Suzuki, Yoshihiro Hori, Yoshiharu Uchihara, Satoshi Sumi, Toshiaki Hioki, Yoshiteru Murakami, Masahiko Kaneko. Hypermedia Research Center, SANYO Electric Co., Ltd., SPIE vol. 3401. Pp. 2-5.
“High Frequency Wobbles: A Write Clock Generation Method for Rewritable DVD That Enables Near Drop-In Compatibility with DVD-ROMS,” Daniel Abramovitch, David Towner, Craig Perlov, Josh Hogan, Michael Fischer, Carol Wilson, Ilkan Cokgor and Carl Taussig. Hewlett-Packard Laboratories, Storage Technologies Department. ODSC99 For submission to the ODSC. Pp. 1-3.
ECMA/TC31/99/7, Draft Standard ECMA-XXX, Februari 1999, “ECMA Standardizing Information and Communication Systems,” “120 mm ReWritable DVD (DVD + RW) Capacity: 4,7 Gbytes and 9,4 Gbytes,” First Draft, p. i-vii, p. 1-82, URL: http://www.ecma.ch.
Hewlett-Packard Company, L.P.
Le Kimlien T.
Neudeck Alexander J.
Young W. R.
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