Kabushiki Kaisha Toshiba

Matsushita Electric Industrial Co., Ltd.

Pioneer Electronic Corporation

Other

Hitachi, Ltd.

Kabushiki Kaishi Toshiba

Panasonic Corporation

Koichi Hirayama

Masatoshi Nakai

Kenji Shimoda

Hideo Ando

Chosaku Noda

Tadashi Kojima

Shin-ichi Tanaka

Yuichi Miyano

Yutaka Kashihara

Yutaka Okamoto

Toshiyuki Shimada

Naoki Endoh

Kenjiro Endoh

Makoto Tatebayashi

Takehisa Kato

Yoshihisa Fukushima

Hisashi Yamada

Shinichi Tanaka

Takao Arai

Toshifumi Takeuchi

Yoshiaki Moriyama

Fumihiko Yokogawa

Motoji Ohmori

Hiroaki Unno

Natsume Matsuzaki

Mitsurou Moriya

Takashi Yumiba

Yoshiyuki Ishizawa

Masatoshi Shimbo

Hiroharu Satoh

Akira Kurahashi

Shinya Yamada

Atsushi Ishihara

Taku Katoh

Fumihiko Pioneer Electronic Corp Yokogawa

Yoshiaki Pioneer Electronic Corp Moriyama

On a recording medium, first information obtained by enciphering data with the first key and second information obtained by enciphering the first key with each of the predetermined second keys are recorded. A deciphering method is characterized by comprising the steps of inputting the first and second information, deciphering the first key using at least one of the second keys, determining by a specific method that the obtained first key is correct, and then deciphering the data using the first key to obtain the data.

Method and apparatus of enciphering and deciphering data using keys enciphered and deciphered with other keys

An information recording medium includes a management area where management information is recorded and a plurality of physical sector areas used to record a plurality of physical sector data blocks, which are generated by combining some data contained in a plurality of ECC blocks.

Information recording medium on which sector data generated from ECC block is recorded, information recording apparatus for recording sector data, and information reproduction apparatus for reproducing sector data

A reproduction signal evaluation method of this invention includes the step of obtaining a reproduction signal from an information recording medium on which digital information is recorded with record marks having different sizes, the step of obtaining the amplitude of a first reproduction signal, of the signals contained in the reproduction signal, which reflects digital information recorded with a record mark having the maximum size, the step of obtaining the amplitude of a second reproduction signal, of the signals contained in the reproduction signal, which reflects digital information recorded with a record mark having the second smallest size, the step of obtaining an evaluation value from the ratio of the amplitudes of the first and second reproduction signals, and the step of evaluating a characteristic of the reproduction signal on the basis of the evaluation value.

Reproduction signal evaluation method

A transmitting method of digital data whereby information data can be reproduced at a high precision. In order to retain digital data in sectors comprising a plurality of sync frames and sequentially transmit, the sync frame is comprised of the sync signal and the run length limited code which satisfies the limitations of the minimum run length and the maximum run length, and the sync signal includes the sync pattern constituted by a bit pattern of a run length that is longer than the maximum run length by onlyT and addition bit patterns which are arranged before and after the bit pattern and each of which has a urn length that is longer than the minimum run length. The sync signal includes a specific code which indicates a position in the sector and which enables the DC control to be performed.

Digital data transmitting method

A record medium comprises an original data obtained by superimposing a presentation target data, to which an error correction encoding is performed and an identification information.

Record medium, record medium manufacturing device, computer readable record medium on which program is recorded, and data presentation device

An estimation method produces a reproduction signal while reading from an information recording medium such as an optical disk, and uses an equalizer to produce an equalization signal. The method then synthesizes distribution levels of the equalization signal that range over distributions of (n+1) levels L, L, . . . , Ln (in which L&#x3c;L. . . &#x3c;Ln and n&#x3e;2), thereby creating a new distribution. The method then uses the standard deviation of the new distribution as an estimation reference value to estimate the quality of an information reproduction apparatus or the quality of the information recording medium. The quality estimate may be used to adjust a circuit in an information reproduction apparatus that reads the information recording medium.

Method for estimating the quality of an information recording medium utilizing equalization signals

There are provided a modulation table, a selector, and a counter. The modulation table is used for creating a plurality of modulation data candidates with respect to a mixture of user data and training data. The selector selects modulation data candidates. The counter counts DSVs for the selected modulation data and controls the selector. The DSV output from this counter is set to a specified value by keeping a state in which the training data is input.

Information recording and reproducing apparatus and information recording and reproducing method, information reproducing apparatus and information reproducing method, and information recording medium

An information storage medium has a plurality of reference data recording areas that record reference data which is used in at least one of circuit constant adjustment of an information reproduction apparatus and characteristic evaluation.

Information storage medium, information recording method, and information reproduction method

Growing community of inventors

Yokohama, Japan

Koichi Hirayama