Abstract: 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.

Abstract: Information is recorded on a rewritable optical disk apparatus in accordance with the second generation 5 inch rewritable-type optical disks standards that provide for reusing once-defective user blocks. Such disks have a user data recording region, a replacement recording region and a replacement control information recording region in which a table of information linking defective blocks in the user data recording region with replacement blocks in the replacement recording region is stored. Continuity of the distribution of the replacement recording blocks is maintained by treatment of replacement blocks that become unnecessary. Unnecessary replacement blocks are ones that are not used for storing data because of the subsequent successful recording of data in once defective user blocks to which the replacement blocks were previously linked.

Abstract: A recording apparatus for making soundless information on a recording medium uniform in length by detecting a soundless portion of an input signal and overwriting the soundless portion detected to continue for a period longer than a predetermined time on a soundless portion already recorded on the recording medium till the audio data enters a sounding state.

Abstract: A data erasure device for an optical recording medium which controls the effects of a temperature rise of an optical recording medium during an erasure operation. The data erasure device irradiates a light beam on a recording medium, and erases data recorded on the medium by increasing the temperature of a portion of the recording medium irradiated by the light beam. The light beam is caused to blink between two states during the erasure operation to produce a uniform erasure mark.

Abstract: A disc playback system monitors coded information in the tracks of discs being played back in order to determine the radial position of the information pickup apparatus. Responsive to a disc stop command, the radial position is utilized to determine the angular speed of the disc, and thereby the speed of the motor that is rotating the disc. A time period, necessary for a predetermined signal which accelerates the motor in the reverse direction to stop the rotation of the disc, is calculated in response to the angular speed at the time the stop command is instituted. Thereafter the predetermined reversing signal is applied to the motor for the calculated period to stop the rotation of the disc.

Abstract: An optical disk replay device for replaying information from an optical disk recorded in a modified constant angular velocity (MCAV) format. The optical disk replay device has an optical head to output a reproduced signal based on the information stored in the optical disk. The signal from the optical head is passed through a series of delay circuits which output delayed signals based on the reproduced signal. Thereafter, a calculating circuit sums, or subtracts, the delayed signals and outputs an intermediate reproduced signal to a band limiting circuit which attenuates the frequency of the intermediate reproduced signal. A control circuit changes the amount of delay imparted by the delay circuits and to adjust the frequency range of the band limiting circuit.

Abstract: An optical scanning device can scan two types of record carriers each having a transparent layer with a different thickness, in which a radiation beam scans an information layer of the record carrier through the transparent layer. When scanning a first type of record carrier the best focus of a scanning radiation beam is positioned on the information layer and when scanning a second type of record carrier the paraxial focus of the radiation beam is positioned on the information layer.

Abstract: An optical storage disk for use in an optical storage system includes a storage layer which is capable of being disrupted when a laser beam of sufficient intensity is focused thereon. The optical storage disk has a transparent substrate layer on one side of the storage layer and a lacquer layer on the other side of the storage layer. The disruptions provided by the laser beam are selected to provide human readable and/or machine readable patterns. To reduce the damage to portions of the optical disk other than the storage layer, the storage layer is exposed to the laser beam prior to curing, or prior to applying and curing the lacquer layer. The optical disk can be of the type with data written thereon during fabrication, or the disk can be of the type in which data can be impressed thereon after fabrication of the optical disk. The patterns on the optical disk can be in the form of optical bar codes.

Abstract: An optical device comprises a light-emitting portion (4), a converging means (3), and a light-receiving portion (5), wherein light (L.sub.F) emitted from the light-emitting portion (4) is converged and irradiated by the converging means (3) on an irradiated portion (2) and returned light (L.sub.R) reflected from the irradiated portion (2) also is converged by the converging means (3), the light-receiving portion (5) is disposed near a confocal position of returned light (L.sub.R) from the irradiated portion (2) of the converging means (2), light (L.sub.F) emitted from the light-emitting portion (4) is passed through a light path of the same axis and received by the light-receiving portion (5) before and after it is reflected on the irradiated portion (2), and the light-receiving portion (5) detects a signal based on a push-pull method.

Abstract: An optical head for reproducing data from first and second optical disks which are different from each other in at least one of a base material thickness and an available wavelength, includes: a first light source for emitting a first light beam, the first light beam being used for reproducing data from the first optical disk: an optical system designed to converge the first light beam onto the first optical disk in accordance with a base material thickness and an available wavelength of the first optical disk: and a second light source for emitting a second light beam, the second light beam being used for reproducing data from the second optical disk, wherein an optical path length between the second light source and the optical system is different from an optical path length between the first light source and the optical system, and wherein the optical system converges the second light beam onto the second optical disk.

Abstract: An optical disk apparatus has an optical pickup, a cosine equalizer having frequency characteristics including a boosting frequency for a frequency component which has a frequency that is about twice the frequency of an RF signal reproduced from recorded data with a shortest data length, and a digital signal processor for generating recorded data from the RF signal. Irrespective to the type of reproduced data from the optical pickup, the optical disk apparatus greatly increases the quality of the reproduced data as information transfer accuracy as compared with a conventional disk optical system.

Abstract: A reproducing apparatus in which a reproduction signal reproduced from a recording medium is temporarily stored in a memory and is thereafter read out, and in which, when the amount of accumulation of the reproduction signal stored in the memory becomes equal to or larger than a predetermined value, a function of at least one section of the reproducing apparatus is inhibited. A part of at least one of a program read out from the memory before the inhibition of the above-mentioned function and other programs before and after the program read out from the memory is previously stored in the memory. Therefore, even if an access to such a program is requested while the function of the related section of the reproducing apparatus is inhibited, the part of the program can be read out to immediately obtain the desired reproduction output.

Abstract: A reproducing apparatus for a disc-like recording medium in which administration information of recorded information is recorded together with the information has a stocking section, a reproducing section, a transferring mechanism, a memory and a controller. A plurality of disc-like recording media are stocked in the stocking section in a laminate fashion. The reproducing section reproduces the information and the administration information recorded in the disc-like recording medium. The transferring mechanism selectively picks up the disc-like medium from the stocking section and transfers the picked-up recording medium between the stocking section and the reproducing section and transfers the recording medium to an eject position from the reproducing apparatus. The memory stores the administration information of the recording medium read out or reproduced by the reproducing section and information concerning a reproduction order.

Abstract: Detecting blank sectors in an optical disk is disclosed. Such detection operates by sampling a target data field of a sector on the optical disk and generating a read peak signal based upon the sampling. The read peak signal is then compared to a predetermined amplitude threshold. A counter is incremented if the read peak signal is less than the predetermined amplitude threshold. After the above steps are performed a predetermined number of times, the counter is compared to a predetermined sample threshold value. Then, the sector is interpreted as being blank if the counter is greater than the predetermined sample threshold value. If, instead, the counter is less than the predetermined sample threshold value, then the sector is interpreted as being non-blank.

Abstract: Laser light is focused in an accurate manner on selected layers in a multilayer optical disk recording system by means of an analysis of output electrical signals from a dithered source which results in the production of an electrical signal which is proportional to an amount by which the parts of the system are to be relatively moved in order to achieve the desired focus on one of the layers.

Abstract: A data unit is constructed of a header, sound data, and image data. The sound data and the image data are data sampled at predetermined unit time intervals. These data are divided at predetermined positions of the unit. The header and sound data are fixed length type data. The image data may be fixed length type data or variable length type. Even if the image data is compressed variable length type data, because the sound data is fixed length type data, the recording time of the sound data on a medium can be predicted. Even if a non-correctable error takes place at the header, because the divided positions of these data are fixed, each data can be separated and reproduced from the unit.

Abstract: A compatible information reproducing apparatus which performs optimum signal processes corresponding to the kinds of a target recording medium for read signals read out from the target recording medium in which digital data signals have been stored and which can accurately reproduce the recorded digital data. The information reproducing apparatus of different recording media each storing a digital data signal is constructed by: a reading system (1, 2, 5) for reading out the digital data signal recorded on a target recording medium (3) and forming a read signal; an A/D converter (11) for A/D converting the read signal and sequentially forming a reproduction sample values; a prediction value setting circuit (13') for forming prediction values in accordance with the kind of a target recording medium; and a Viterbi decoder (12) for performing a Viterbi decoding based on the prediction values for the reproduction sample values, thereby forming a reproduction digital signal.

Abstract: The present invention relates to methods and apparatus for reproducing encoded data recorded on a disk and decoding the reproduced encoded data. The data reproduced from the disk in encoded form are stored in a buffer and read from the buffer for carrying out error correction. Once the data have been error-corrected, the error corrected encoded data are again stored in the buffer. Then the data are read from the buffer for decoding.

Abstract: In a data recording apparatus which sequentially records recording data on a magnetic tape (T), when a plurality of continuously recorded data files F(i) are rewritten into new data files F(I) having smaller data quantities, recording areas which remain without being rewritten into the new data files F(I) are rewritten into unrecorded areas NR containing no data. Further, when rewriting into new data files G(I) which have larger data quantities, reserve areas SP are provided, in which data has not been previously recorded, and overflow data is written into the reserve areas SP at the time of rewriting.

Abstract: During recording the inputted data are sequentially written into a memory at one transfer rate and are read out at a second, higher transfer rate for recording on a record medium. The reading of the memory is such that data in a preset first amount are successively read from the memory to always ensure a write space in the memory which has a capacity which is higher than a predetermined second amount when the amount of the inputted data stored in the memory exceeds the first amount. During playback, the recorded data are reproduced at a second transfer rate, which is higher than a first transfer rate required for outputting the reproduced data, and are written in the memory. The thus written data are successively read out of the memory as reproduced output data at the first transfer rate.