Abstract: 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.

Abstract: 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.

Abstract: Disclosed herein are a disc recording medium, a recording apparatus and a playback apparatus, more concretely, the present invention provides a disc recording medium wherein a circular track is created in advance to be used for recording data as a groove or a land, said track is wobbled to contain approximately fixed number of wobbling periods as counted in a longitudinal direction of said track, and said track includes rotational-angle marks each showing a predetermined rotational angular position on said disc recording medium. As a result, the precision and the reliability of recording can be attained.

Abstract: 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+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+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+1 using normal write clock. It then performs the replacement procedure on the area A+1. Thereby, it prevents the disadvantage such as a tracking servo failure in the areas A and A+1.

Abstract: There are provided a spindle motor 12, an optical head 20, a high-pass filter 31, low-pass filters 32 and 33, an adder 38, and a PLL 39. The spindle motor 12 rotatively drives an optical disk 11. The optical head 20 irradiates a laser beam onto a target track and both tracks adjacent to the target track on the optical disk 11 and detects a return light from each track. The high-pass filter 31 filters a high-frequency component in a signal used for detecting a return light from a target track in the optical head 20. Each of the low-pass filters 32 and 33 filters a low-frequency component in a signal used for detecting a return light from each of the adjacent tracks. The adder 38 operates output signals from the high-pass filter 31, and the low-pass filters 32 and 33. Based on a signal from the adder 38, the PLL 39 generates a reference signal used as a time reference for generating recording signals. An operation by the adder 38 nullifies a cross modulation component.

Abstract: 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+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+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+1 using normal write clock. It then performs the replacement procedure on the area A+1. Thereby, it prevents the disadvantage such as a tracking servo failure in the areas A and A+1.

Abstract: 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.

Abstract: 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.