Matsushita Electric Industrial Co., Ltd.

Akira Mutoh

Shin-ichi Tanaka

Takashi Ishida

Isao Satoh

Shunji Ohara

Yoshinari Takemura

Nobuo Akahira

Yoshiharu Kobayashi

A code conversion method and apparatus is provided for scrambling and modulating data. The method and apparatus includes scrambling an input main data unit based on any of plural types of pseudo-random number sequences, and modulating the scrambled main data unit based on any of plural types of modulation data. An output main data unit is produced from the modulated main data unit, and a calculated value representing a difference between a number of 0 bits and a number of 1 bits included in the output main data unit is obtained. Any of the modulation data is then selected dependent upon the calculated value. The method and apparatus further includes determining whether or not a variation of the calculated value has exceeded a predetermined threshold, newly selecting another pseudo-random number sequence used for the step of scrambling if it is determined that the variation of the calculated value has exceeded the predetermined threshold value, and re-scrambling the input main data unit based on the newly selected pseudo-random number sequence.

Code conversion method and apparatus, code recording medium, code recording apparatus and code reproducing apparatus

In an optical disc, an ID field contains a plurality of address information, and is preliminarily recorded in convex and concave signals, and is composed of two sets offset by about track pitch toward the internal or external track direction adjacent to the guide track, an information recording field is composed of grooves and lands oscillating at a single frequency in the radial direction, and the grooves and lands alternate in every revolution of the guide track. When w bits of information are included in one period of oscillation, an information unrecorded field between the ID field and information recording field is arranged to have a length of w/10 bits or more and/or w bits or less, and therefore, when recording continuous information data such as video data, it is possible to record continuously by generating a clock securely from the oscillating signal, and moreover, the format efficiency is improved, so that a format of a larger capacity is achieved.

Optical disc having oscillating lands and grooves

One or more optical discs, each having a ROM field having information with a length of at least one track formed in convex and concave pit rows, and a rewritable field capable of rewriting the information with a length of at least one track, an information unrecorded field having a length of at least one track located between the ROM field and rewritable field, the rewritable field having a spiral or concentric guide track oscillating in a radial direction, the ROM field having spiral or concentric convex and concave pit rows, and at least a part field at the rewritable field side of the information unrecorded field has a transition field having a spiral or concentric guide track oscillating in the radial direction continuously or intermittently and a track pitch To of the ROM field and a track pitch Tw between grooves and lands of the rewritable field have values such that To&gt;Tw.

Optical disc having oscillating land and grooves

In an optical disc, an ID field contains a plurality of address information, and is preliminarily recorded in convex and concave signals, and is composed of two sets offset by about 1/2 track pitch toward the internal or external track direction adjacent to the guide track, an information recording field is composed of grooves and lands oscillating at a single frequency in the radial direction, and the grooves and lands alternate in every revolution of the guide track. When w bits of information are included in one period of oscillation, an information unrecorded field between the ID field and information recording field is arranged to have a length of w/10 bits or more and/or w bits or less, and therefore, when recording continuous information data such as video data, it is possible to record continuously by generating a clock securely from the oscillating signal, and moreover, the format efficiency is improved, so that a format of a larger capacity is achieved.

Growing community of inventors

Sakai, Japan

Akira Mutoh