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: An optical recording/reproducing apparatus having drive means for rotating a recording medium, an optical head for applying light to the recording medium being rotated by the drive means, thereby to record data signals on the recording medium or reproducing data from the recording medium, and a signal-processing circuit for processing a signal detected by the optical head. The optical head comprises a light source for emitting light, an objective lens, and signal detecting means. The objective lens has a numerical aperture NA, where 0.5<NA≦0.6. The apparatus can reliably record data on and reproduce data from high-density optical recording media that have different track pitches.

Abstract: To enable a plurality of types of optical discs different in recording density from each other and quickly getting “ready” for writing and/or reading data to and/or from each of such optical discs, various controlling conditions requisite for the data writing and reading operations are stored in a memory for both optical discs having first and second recording densities, respectively. For a shorter time up to a “ready” state for data write or read, a controller makes an instant discrimination, based on the pattern of a sync signal “SYNC” included in an ATIP wobble signal supplied from an ATIP decoder, between the optical disc having the first recording density and that having the second recording density, reads, from the memory, controlling conditions corresponding to the result of the disc type discrimination, and sets operating parameters for each component of the optical disc drive.

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: An optical recording/reproducing apparatus having drive means for rotating a recording medium, an optical head for applying light to the recording medium being rotated by the drive means, thereby to record data signals on the recording medium or reproducing data from the recording medium, and a signal-processing circuit for processing a signal detected by the optical head. The optical head comprises a light source for emitting light, an objective lens, and signal detecting means. The objective lens has a numerical aperture NA, where 0.5<NA≦0.6. The apparatus can reliably record data on and reproduce data from high-density optical recording media that have different track pitches.

Abstract: To enable a plurality of types of optical discs different in recording density from each other and quickly getting “ready” for writing and/or reading data to and/or from each of such optical discs, various controlling conditions requisite for the data writing and reading operations are stored in a memory for both optical discs having first and second recording densities, respectively. For a shorter time up to a “ready” state for data write or read, a controller makes an instant discrimination, based on the pattern of a sync signal “SYNC” included in an ATIP wobble signal supplied from an ATIP decoder, between the optical disc having the first recording density and that having the second recording density, reads, from the memory, controlling conditions corresponding to the result of the disc type discrimination, and sets operating parameters for each component of the optical disc drive.

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.