Sony Corporation

Hiroshige Okamura

Seiji Kobayashi

Toshiyuki Nakagawa

Hisayuki Yamatsu

Minoru Tobita

Toshiyuki Kashiwagi

Yoshihiro Tsukamura

Selji Kobayashi

Takanori Takemoto

The present invention pertains to a modulation apparatus and method in which the modulation apparatus is realized with a simple circuit structure and is easily applicable to other systems. A pattern conversion unitconverts data having a basic data length of 2 bits supplied from a DSV control bit determination and insertion unitinto a variable-length code having a basic code length of 3 bits in accordance with a conversion table. A minimum-run-length limitation code detection unitdetects, from a data sequence containing a DSV control bit, the position of minimum runs consecutive from a channel bit string converted by the pattern conversion unit. A consecutive-minimum-run replacement unitreplaces a predetermined portion of the channel bit string supplied from the pattern conversion unitfor a predetermined pattern based on the position information supplied from the minimum-run-length limitation code detection unit, and limits the minimum run length to a predetermined number or less. The present invention is applicable to a modulation apparatus.

Modulation apparatus and method

The present invention is associated with a recording medium in which, to a data part constituted by frames obtained by attaching a synchronous signal to the data divided by a predetermined data length, data having a preamble part and a postamble part attached with at least one synchronous signal having a pattern different from that of the synchronous signal attached to the data part are recorded, a reproducing apparatus for reproducing this recording medium, and a recording apparatus for recording data to this recording medium.

Recording medium, reproducing apparatus, and recording apparatus

A modulation apparatus and method for more accurately determining a value of a control bit to be inserted into a data sequence and digital sum value (DSV) control bit generating method in which a data conversion unit supplies modulation-delimiter information including information regarding delimiters of modulation of a data sequence based on a conversion table to a modulation-delimiter detecting unit and supplies to a valid-delimiter detecting unit a DSV-segment-delimiter signal including information regarding a delimiter position of a DSV segment of the data sequence having the DSV control bit. The modulation-delimiter detecting unit detects modulation-delimiter positions based on the modulation-delimiter information supplied thereto and supplies a modulation-delimiter signal to the valid-delimiter detecting unit. The valid-delimiter detecting unit, based on the DSV-segment-delimiter signal supplied thereto, detects a valid-delimiter position for controlling timing for determining a DSV control bit of the relevant DSV segment from the modulation-delimiter positions represented by the modulation-delimiter signal supplied thereto.

Modulation apparatus and method, and DSV-control-bit generating method

The present invention relates to a modulation apparatus and method and a DSV-control-bit generating method for suppressing an increase in circuit size of the modulation apparatus. When an input data stream is supplied to a DSV control bit determination unit, the DSV control bit determination unitdetermines a DSV control bit to be inserted into the input data stream. Upon supplying the input data stream to the DSV control bit determination unit, the input data stream is simultaneously supplied to a delay processor. The input data stream is delayed for a predetermined delay time and supplied to a determined-DSV-control-bit insertion unit. The determined-DSV-control-bit insertion unitinserts the DSV control bit determined by the DSV control bit determination unitinto a predetermined position of the input data stream supplied by the delay means and supplies the input data stream containing the DSV control bit to a modulator. The modulatormodulates the input data stream containing the DSV control bit into a code string in accordance with a predetermined coding rule (for example, 1,7PP modulation).

Modulating apparatus and method, and DSV control bit producing method

Modulation apparatus and method and DSV control bit generation method

Digital information is recorded with high density. Positions of a leading edge and a trailing edge of an information pit are shifted from a reference position indicated by a leading edge of a reference clock in a step-wise fashion in respond to digital data to be recorded.

Reproducing apparatus using an information recording medium wherein

In an information recording medium from which information recorded on each pit is reproduced by an optical detection system that obtains a reproduced signal corresponding to each pit by scanning the information recording medium along pit rows by a light beam, data of high recording density can be accurately reproduced by a simple arrangement by shifting in a step-wise fashion edge positions of an information pit from a predetermined reference position in response to digital information to be recorded within a range corresponding to a predetermined shift period smaller than a transition period of a reproduced signal determined in response to a transfer characteristic of the optical detection system. Therefore, a nonlinear intersymbol interference can be reduced without emphasizing a noise component.

Information recording medium with pits edges shifted in a step-wise

Digital information is recorded with high density. Positions of a leading edge and a trailing edge of an information pit are shifted from a reference position indicated by a leading edge of a reference clock in a step-wise fashion in response to digital data to be recorded.

Information recording medium wherein digital symbols are represented by

Information recording medium wherein multi-bit digital information is

Information recording apparatus and process for recording on a recording

Information recording medium and a recording apparatus and a reproducing

Reproducing apparatus for reproducing information from a recording

Magneto-optically recorded data can be recorded at high density, such that the data can be overwritten by a simple arrangement and with a small energy. Also, data of high recording density can be accurately recorded and reproduced by a simple arrangement. An alternating field having the same frequency as that of a recording fundamental clock generated by a PLL circuit (8) is generated by a coil (5) that is part of a tank circuit (7) and then applied to a magneto-optical disc (1). A phase of the recording fundamental clock is modulated by a phase modulating circuit (12) in association with recording data and a pulse synchronized with leading edge and trailing edge of such clock is generated by a pulse generating circuit (13). An optical pickup device (4) irradiates the magneto-optical disc (1) with a laser light in synchronism with the pulse. Therefore, a high density recording method in which the edge position of pit is shifted stepwise in association with data to be recorded can be applied to a magneto-optical recording medium.

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Kanagawa, Japan

Hiroshige Okamura