Sony Corporation

Satoshi Kumai

Eiji Kumagai

Kenji Nagashima

Toshio Morizumi

Toru Takeda

Tetsuji Kawashima

Junichi Suzuki

Norichika Mine

Ayumi Konishi

Yoshihiro Horibata

After the initiation of writing, an output signal from an LPF is sampled in correspondence with a portion with a predetermined pulse width of recording data, so as to obtain a pit level. In the resultant signal, its varying portions which correspond to the multi-pulse trains of the write signal are smoothed. A controller modifies a level of a target level signal to be supplied to an APC circuit in such a manner that the pit level becomes an optimum pit level which has been obtained prior to the initiation of writing.

Optical recording apparatus, and method for controlling laser power therein by filtering and then sampling a returned light signal

In a CIRC encoder for carrying out error correction coding processing with a CIRC, a first interleaver and a second interleaver are provided which have different delay parameters, and these interleavers are switched in accordance with the recording density of an optical disc for recording data. Also, in a CIRC decoder, a first deinterleaver corresponding to the first interleaver and a second deinterleaver corresponding to the second interleaver are provided, and these deinterleavers are switched in accordance with the recording density of an optical disc for reproducing data. A recording/reproducing system is realized which is capable of carrying out appropriate recording and reproduction of data to and from an optical disc having a higher recording density can be carried out and is also capable of handling an optical disc of an existing format.

Data recording device, data reproducing device, and optical disc

This invention relates to a data recording method or the like preferably being applicable to a case where it records data on an optical disc such as DVD&plus;RW disc. When writing the data on block area A, if no normal write clock occurs correctly, it stops writing the data and performs replacement procedures on the area A. It then writes predetermined data on the area A using reference clock. It also records the data on next block area A&plus;1 across the area A, thereby preventing the area A from generating blank portion therein on its rear side based on nonuniform rotation of the optical disc, etc. It records the data on the area A&plus;1 using normal write clock. It then performs the replacement procedure on the area A&plus;1. Thereby, it prevents the disadvantage such as a tracking servo failure in the areas A and A&plus;1.

Data recording method and data recording apparatus

There are provided a spindle motor , an optical head , a high-pass filter , low-pass filters and , an adder , and a PLL . The spindle motor rotatively drives an optical disk . The optical head irradiates a laser beam onto a target track and both tracks adjacent to the target track on the optical disk and detects a return light from each track. The high-pass filter filters a high-frequency component in a signal used for detecting a return light from a target track in the optical head . Each of the low-pass filters and filters a low-frequency component in a signal used for detecting a return light from each of the adjacent tracks. The adder operates output signals from the high-pass filter , and the low-pass filters and . Based on a signal from the adder , the PLL generates a reference signal used as a time reference for generating recording signals. An operation by the adder nullifies a cross modulation component.

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Kanagawa, Japan

Satoshi Kumai