Abstract: An optical disk drive which discriminates whether a light spot is incident on a groove or on an area therebetween by eliminating a pulse that appears in a binary envelope signal when the light spot passes a level section. The elimination is carried out based on an ODF section detecting signal, the ODF section detecting signal being a level section detecting signal which is produced by detecting a level section (ODF section) of the optical disk. The detection is carried out by differentiating an envelope signal, which is the envelope of an electric signal corresponding to the amount of light reflected from the optical disk. Accordingly, even if the optical disk in use has interrupted grooves, the optical head can be accurately moved to a desired track located on a land or on a groove.

Abstract: An optical disk recording and reproducing apparatus in which during coarse access, an adjustable target speed is obtained using a speed offset value stored in a speed offset memory. The speed offset value being determined between a plurality of reference velocities and a plurality of adjustable offset velocity values. The system also performs fine access within a defined distance from the optical head to the designated track upon completion of the coarse access mode. The speed offset values are continually updated by to improve the accuracy of the coarse access operation saving overall access time.

Abstract: Disclosed are a magnetic recording and reproduction apparatus for a data processing unit, which includes a plurality of magnetic heads formed integrally by a thin-film forming technology, and a magnetic tape. A magnetic tape has a plurality of recording tracks corresponding to a plurality of independent data. The recording tracks are arranged in parallel to a moving direction of the magnetic tape and share the same starting position. A plurality of magnetic heads are arranged in parallel to a width direction of the magnetic tape to correspond to the recording tracks in a one-to-one correspondence, and are fixed at the starting position of the recording tracks. The magnetic tape is moved in a direction in which the starting position is away from the magnetic heads for data recording onto the magnetic tape and for data reproduction from the magnetic tape.

Abstract: An apparatus for recording and reproducing information on and from an optical disk is disclosed in which at least one optical beam and a reference clock signal are used. The optical disk comprises recording tracks which are divided into a plurality of blocks and concentrically arranged along the radial direction. The apparatus comprises: a block judging unit for judging one of the blocks that the one block is currently impinged by the optical beam; a clock signal generator for generating a plurality of clock signals which are different in frequency from each other; and a clock signal selecting unit for selecting one of the clock signals as the reference clock signal, on the basis of the judgement of the block judging unit.

Abstract: A recording and reproducing device, which records and reproduces information on and from a rewritable recording medium having absolute addresses and including an information recording area wherein information entered from external devices is recorded and a Table of Contents area wherein additional address information with respect to the information recorded in the information recording area is recorded. The TOC area contains the absolute addresses of the recording positions of each information recorded in the information recording area. A display section graphically and independently displays the recorded and unrecorded ranges of the information recording area according to the absolute addresses recorded in the TOC area with respect to the recording positions of each piece of information.

Abstract: An information recording and reproducing device uses a disk-shaped recording medium which is rotated at a constant angular velocity. The recording medium is divided into a plurality ring-shaped zones of concentric circles. In a recording area of the recording medium, the number of sectors per track is uniform in each zone and the number of sectors increases from an innermost zone towards an outermost zone. Each sector has a header area wherein header information including address information is recorded and a data area wherein data is recorded. In this device, data is recorded and reproduced in the data area in accordance with clock signals whose frequencies increase from the innermost zone towards the outermost zone. This device has a first clock generating circuit for generating a first clock signal of a fixed frequency, and the header information is recorded and reproduced in the header area in accordance with the first clock signal.

Abstract: In the optical recording element of the invention, alignments of long thin pits inclined in various directions with respect to the track direction are formed on the tracks and information is recorded therein according to the different inclines of the pits, thereby performing higher-density and larger-volume recording without reducing the spacing between each pit and the track pitch. The invention also discloses an optical data retrieval system for use with the above optical recording element, which scans the pit alignments with a laser beam spot, detects the inclines of the pits by obtaining the distribution of the intensity of reflected light which is caused by light diffraction at the pits, and plays back information in accordance with the inclines. Therefore, not only can the substantially same structure as that of a standard type optical data retrieval system be applied to the invention without making any complicated change, but also cross-talk is less likely to be produced in the read out signals.

Abstract: A cartridge case for containing a disk-shaped recording medium has a shutter attached slidably thereon. The shutter is U-shaped sectionally and the edge sections where the shutter contacts the surface of the cartridge case are rounded so that friction therebetween is reduced when the shutter slides on the surface of the cartridge case. The cartridge case is provided with a notch and an indentation on at least one of its side surfaces corresponding to protruding pieces in the device into which the cartridge case is inserted such that a sensor in the device can be activated only when a cartridge case compatible with the device is inserted and these protruding pieces properly engage with the notch and the indentation on the cartridge case.

Abstract: An optical disk recording/reproducing device for recording or reproducing information on or from an optical disk while rotatively driving the optical disk at a constant angular velocity. The disk has pre-recorded information cyclically formed along a track so as to provide rotation control at a constant linear velocity. The device, which includes a clock generating circuit for generating a clock signal for recording or reproducing in accordance with a recording frequency of the pre-recorded information derived from signals reproduced by an optical head, is designed to perform recording or reproducing operations with a recording frequency according to the clock signal. The device further includes a magnetic filed control circuit and a recording light power control circuit whereby a magnetic field and light power to be applied to the optical disk is varied according to the recording frequency during recording operations.

Abstract: The invention provides an improvement of the conventional laser driving circuit mainly including a control logic circuit, a reproducing power producing circuit, and a recording power producing circuit for preventing a recording film of a disk from being damaged by a laser in a reproducing mode. The improved respect is addition of a voltage monitoring circuit and a bypass transistor for an abnormal signal. The voltage monitoring circuit monitors a voltage drop caused in the control logic circuit and supplies a voltage abnormality indicating signal, thereby causing the bypass transistor to be conductive for allowing the abnormal signal to be flown therethrough.

Abstract: A digital signal reproduction apparatus includes a first differential circuit for differentiating a reproduction signal reproduced from a recording medium. This differential circuit outputs a first order differential signal. A second differential circuit differentiates the first order differential signal of the reproduction signal and outputs a second order differential signal. A comparator compares the second order differential signal with a predetermined level to produce a window signal. A peak detecting circuit detects zero-cross points in the first order differential signal and outputs a peak detecting signal. A gate gates the peak detecting signal with the window signal to output a reproduction data signal.

Abstract: In a recording/reproducing device in accordance with the present invention, recording or reproducing positions are recognized by using absolute address parts which are predeterminately formed in a rewritable recording medium. Moreover, the device is composed so that the user can easily edit reproducing procedures stored in memory means with respect to each information in the recording medium by using the recording or reproducing positions read from above-mentioned absolute address parts and he/she can also rewrite above-mentioned reproducing procedures edited by him/her in the lead-in region of the above-mentioned recording medium.

Abstract: A recording/reproducing device performs the recording/reproduction on a recording medium having an information recording area and a table of contents area. The recording medium is provided with guiding grooves that snake in cycles corresponding to values of absolute addresses. The device divides the information recording area into a plurality of domains. Each domain corresponds to a single sampling frequency with respect to the information being recorded. An electromagnet and an optical head record information in the domain that corresponds to its sampling frequency and records additional information concerning the division in the table of contents. A spindle motor drives the disk which is adjusted such that the velocity of the disk is changed for each domain during recording and reproduction. A demodulator obtains the absolute addresses through demodulation by comparing frequencies determined from the snaking cycles of the guiding grooves with a reference frequency.

Abstract: An apparatus for recording and reproducing information using an optical card comprising a memory region in which one pit train for supplying a track servo signal and a synchronizing signal is formed at a edge portion of the memory region. The optical card achieves increased storing capacity by including only one pit train. The recording/reproduction apparatus for the card has a first and second optical heads. The first optical head scans the pit train to obtain the track servo signal and a synchronizing signal. The second optical head is used for recording and reproducing information from the optical card.

Abstract: An optical memory device for recording, reproducing, or erasing information applies an optical beam such as a laser beam onto a recording medium. The optical memory device includes a recorded region detecting circuit for detecting information recorded region formed in the recording medium. In the optical memory device, a timing control for recording, reproducing, or erasing is performed with the use of a result obtained through detection of a synchronizing signal, such as a sector mark, indicative of a starting point of an information block and another result obtained through detection in the recorded region detecting circuit. The recorded region detecting circuit includes either at least one peak hold circuit for detecting a peak level of the playback signal or a low pass filter for smoothing the playback signal, and a comparator for comparing an output obtained through the peak hold circuit or through the low pass filter with a reference voltage.

Abstract: An optical card comprising a memory region in which one pit train for supplying a track servo signal and a synchronizing signal is formed at a edge portion of the memory region. The optical card achieves increased storing capacity by including only one pit train. A recording/reproduction apparatus for the card comprises first and second optical heads. The first optical head scans the pit train to obtain the track servo signal and a synchronizing signal. The second optical head is used for recording and reproducing information from the optical card.

Abstract: An optical disk recording/reproducing device in accordance with the present invention has a controller that, during recording, performs the rotation control of the optical disk in Constant Linear Velocity according to reproduced signals of pre-recorded information that was pre-recorded on the optical disk, during reproduction, performs the rotation control according to reproduced signals of recorded information, and when the rotation control based on the reproduced signals of the recorded information is infeasible, switches the rotation control and performs the rotation control based on the reproduced signals of the pre-recorded information during reproduction also. As a result, a suitable and appropriate CLV control may be executed during recording and during reproduction.

Abstract: A method of controlling the rotational velocity of an information recording disk having one or more tracks in which patterns and marks are formed, the marks including at least one specific pattern having a predetermined length, which method comprises: measuring a time during which each of the patterns passes; detecting each of the marks on the basis of the values of the measured times; and controlling the rotational velocity of the disk on the basis of the measured time of the specific pattern of the detected mark, thereby making the linear velocity of the detected mark constant.

Abstract: A recording and reproducing device providing control data recording area on erasable type optical recording medium wherein control data are recorded thereof, characterized in that there is provided a control data recording area forming device for forming control data recording areas having more than two control recording blocks which in turn have more than one recording unit. The control data can be recorded independently. A control data updating device records new control data in the control data recording blocks which were the ones not previously being updated with control data, thereby allowing this device to minimize damage caused by electrical power failure.

Abstract: An optical disc medium indexing system having a plurality of elongated parallel tracks wherein each track contains a nonerasable index portion located in less than a single frame. The index portions are formed on the substrate of the disc by a plurality of indentations representing the absolute address of each track on the disc recorded in a multiplex format. Each index portion containing information on the mark, track number and CRC. The disc is constructed so that information may be recorded on the entire surface of the medium including the indexed portions.