Abstract: A method for preventing erroneous recording in compact disc player is disclosed, to prevent erroneous recording and selecting erroneous data during reproduction, wherein the conventional compact disc player is improved in such a manner that a memory is provided so as to store the data temporarily and to delay the recording of the data as required, and errors are detected during the delayed period of time, thereby preventing such a defective music from being recorded.

Abstract: In a disk reproducing device of this invention for reading out data from a disk by means of a pickup element, a speed signal proportional to the speed of relative movement between the disk and the pickup element is created in a case where the pickup element is moved in the radial direction of the disk according to a high frequency signal (RF) read out from the disk and a tracking error signal (TE) derived from the high frequency signal (RF).

Abstract: An optical information recording and reproducing apparatus comprising a first and a second laser diodes for generating recording light and reproducing light, respectively. A light emission condition of the second laser diode is always controlled to the constant or predetermined light intensity which is adequate for reproduction, by an APC circuit. The first laser diode is controlled by a light-intensity control circuit so as to be brought to the intensity of light emission lower than a level which forms a pit on an optical card, in a reproducing mode other than a period of time of a recording mode. Under a focus and tracking control due to the reproducing light, a value of a focus error and a value of a tracking error due to the recording light at a low level are detected and sampled/held as a focus offset and a tracking offset. During a period of time of the recoding mode, focus control and tracking control due to the reproducing light are performed so that these offsets are brought to zero.

Abstract: This invention employs a scheme to extract, from components within a plurality of blocks obtained by subdividing an input signal with respect to time and frequency, every respective blocks, a component or plural components in order of magnitude of components within the respective blocks to determine, on the basis of a difference between magnitudes of components of respective blocks except for the extracted components and magnitudes of the extracted components, a bit allocation ratio to the respective blocks to quantize components of respective blocks on the basis of the bit allocation ratio thus to generate compressed data, thereby making it possible to realize a technique of allocation of bits desirable also from a viewpoint of the auditory sense with respect to such an input signal including, e.g., overtone to much degree. Accordingly, it is possible to carry out efficient compression/expansion of high sound quality from a viewpoint of the hearing sense.

Abstract: In a sound editor, a first editing list is made regardless of the length of a cut and a second editing list for programmed reproduction is thereafter made by retrieving the length of the cuts through a window. When only one cut is found within the window or when a cut is longer than the window, the information concerning the cut is registered in the second editing list as is because no interruption in sound occurs. On the other hands, when a plurality of cuts is found within the window, a new audio material (which is handled together as a single cut from that point on) is recorded. The information about the new cut corresponding to the audio material newly recorded is registered in the second editing list.

Abstract: A write module for an optical tape recorder for optically writing a data signal on light sensitive recording media. The write module comprises a rotated linear edge emitter diode array or vertical cavity emitter diode array comprising a plurality of emitter diodes. The diodes emit a plurality of write beams for writing the data signal on the recording media in a plurality of data channels. An actuator subsystem focuses and positions the write beams on the recording media. The rotation angle of the diode array is a predetermined angle to provide a predetermined separation distance between adjacent data channels. Each write beam is modulated by a designated portion of the data signal to generate a plurality of data signal modulated write beams to optically record the data on the recording media. The data signal modulating each write beam is delayed by a predetermined time value for writing a word of the data signal in adjacent data marks along a line transverse to the length of the data channels.

Abstract: A disc player both translates and rotates a disc using a pair of parallel drive belts contacting opposed edges of a disc. Each drive belt spans a drive pulley and a passive driven pulley. The pulleys are supported on one of two sliding plates. The sliding plates are connected by a pair of pantograph-type rotatable mounting arms such that movement of one drive belt toward the disc forces the other drive belt to move an equal amount toward the disc. Each drive pulley is driven by a motor causing the drive belt to revolve. A spanning portion of each drive belt is urged against the edge of the disc, thereby establishing friction engagement between the belts and the disc such that the disc rotates when the belts rotate. A disc advance control system moves the disc linearly through an optical beam by differing the rotational frequency of one belt relative to the other. Disc advance may be accomplished with, or without, disc rotation.

Abstract: A disk recording medium includes a lead-in area, a program area and a lead-out area. The program area includes: a first track on which a plurality of data signals each of which has a different index from the others is loaded; a second track on which a plurality of programs is loaded, whereby the plurality of programs consists of the sequential combination of the indices of at least one data signal among the plurality of data signals and each program has a different index from the others; a third track on which a data index table comprising the indices of the respective data signals and initial address information is loaded; and a fourth track on which a program index table comprising the indices of the respective programs and initial address information is loaded.

Abstract: A lead-in time reduction system determines if a disk is loaded at the time of turning on an initial focus-on function in a laser disk reproducing apparatus. If it is determined that the disk has been loaded, a pick-up is moved directly to a limit switch-on point using a feed motor only. The lead-in time reduction system includes determining if the disk is loaded by checking whether data is picked-up through the pick-up after the pick-up is located on a focus on point, if it is determined that the disk is loaded in the determining step, controlling the feed motor to move the pick-up directly to a limit switch-on point of the laser disk, and if the limit switch is turned on in the controlling step, reproducing a desired program by using picked-up information after picking up a lead-in region of the laser disk.

Abstract: An equalizer is controlled to equalize a signal read from an optical disc. The equalized signal is supplied to a maximum-likelihood sequence detection circuit, in which a signal sequence is detected to be most coincident to the equalized signal among signal sequences meeting a state transition regularity. The equalizer operates for equalization, only when an error signal is detected in the vicinity of the end of a region having a code transition interval of more than number of minimum transition interval.

Abstract: An information recording/reproducing method is disclosed for an information recording/reproducing apparatus including a recording medium having a disk-like shape, a unit for rotating the recording medium at a constant angular velocity, a unit for recording code information so that the bit length of the code information becomes approximately constant with respect to a radial position on the recording medium, a unit for modulating the code information to be recorded to form a modulated signal, and a recording unit for forming in the recording medium a localized recording region having a different physical property with respect to an unrecorded region, the recording unit being controlled by the modulated signal so that the code information is recorded to correspond to the edge of the recording region, wherein the bit rate of the code information to be recorded changes depending on a location on the recording medium, and a part of each of a recording characteristic of the apparatus and a reproducing characteristi

Abstract: An apparatus reproducing signals recorded on an optical disc rotated at a constant angular velocity. The apparatus employs a binary detector for forming digital data by comparing the reproduced signal with a predetermined threshold level, and a ternary detector for forming reproduced data from two series of digital data detected by comparing the reproduced signal with two different threshold levels of predetermined values. The reproduced data from an outer portion of the disc is detected by the binary detector, while the reproduced data from an inner portion of the disc is detected by the ternary detector. The playback output is selectively switched in response to an address signal of a specific track where the phase margin of the reproduced data detected by the binary detector and the phase margin of the reproduced data detected by the ternary detector becomes substantially equal to each other.

Abstract: To improve the reliability of reproduction by performing signal processing so that substantially (almost) all DC is eliminated when digital data is recorded on a recording medium such as a magneto-optical disk. When data is recorded on a recording medium such as a magneto-optical disk, generally the digital data is modulated and encoded before being recorded, but sometimes the modulation code is not DC free due to a recording channel code of an NRZI system, etc. According to the present invention, data is divided into parts each having a certain constant length so as to prevent the DC component from building up.

Abstract: An apparatus for reproducing digital information from a recording medium having a plurality of parallel tracks and digital information recorded thereon as n-channel (n being an integer greater than or equal to 2) digital signals. The n-channel digital signals are reproduced by n-reproducing heads. The digital information contained in the reproduced signals is stored in a storage device. Discriminating data is obtained for determining which of the n-channel digital signals reproduced correspond to the reproducing heads. The timing of an access device, accessing the storage device for performing a predetermined processing of the digital signals stored in the storage device relative to the reproducing timing of the digital information reproduced by the n reproducing heads, is controlled in accordance with the discrimination data.

Abstract: Pieces of leading compressed information, each of which corresponds to a predetermined number of blocks of each of a plurality of programs recorded on an optical disk, are successively read therefrom, and stored in a buffer memory in a compressed state as they are. Upon reproducing a certain program, the corresponding leading compressed information is read from the buffer memory, and reproduced after having been subjected to a decompressing process in an information-decompression processing circuit. The program is continuously reproduced by reading compressed information corresponding to the predetermined number of blocks following the leading compressed information from the optical disk and supplying the compressed information to the buffer memory. With this arrangement, it is possible to eliminate a slow switching operation in the case when programs are switched to start reproducing a different program.

Abstract: An apparatus for playback of an optical recording medium where data are recorded after combined calculation of a difference signal and a sum signal generated by detecting reference patterns and the return light reflected from the optical recording medium. The recording medium has tracks formed at such a pitch that at least two tracks are scanned simultaneously by a spot of a light beam irradiated onto the recording surface. Each track has data composed of wobble pits formed at positions deviated from the track center and a multiplicity of pits formed exactly on the track center, wherein the multiple pits and the wobble pits are disposed successively. The apparatus comprises an optical detector and a signal discriminator. The optical detector has first and second adjacent light receiving areas divided along the tangential direction of the tracks and serving to receive the return light reflected from the optical recording medium.

Abstract: In case where the predetermined data is recorded on the disc in which divided clusters each having a predetermined section are formed in the track, when it is determined during recording that a cluster is a defective section, the recording is stopped and the recording begins again with a cluster offset from the defective cluster, whereby even if there is a partial defect in the track on the disc, the data can be recorded with accuracy.

Abstract: A disk recording medium includes a lead-in area, a program area and a lead-out area. More specifically, the program area includes a first track on which a plurality of data signals, each of which has a different index from all of the others, is loaded, a second track on which a plurality of programs are loaded, a third track on which a data index table including the indices of the respective data signals and initial address information are loaded, and a fourth track on which a program index table including the indices of the respective programs and initial address information are loaded. The lead-in area is loaded with a table of contents consisting of the initial address information and a plurality of pointers, each of which is different from all of the others each of which designates the respective tracks of the program area and the initial position of the lead-out area.

Abstract: An information detection light intensity control apparatus in an apparatus reproducing information recorded in an optical disc in which a reflectance has a dependency on an incident light intensity, comprising a light source for emitting an information detection light which enters the optical disc and a control system for controlling an intensity of the information detection light which enters the optical disc so that a ratio of an intensity of the information detection light which enters the optical disc and an intensity of the information detection light reflected from the optical disc is set to a predetermined value.

Abstract: An objective lens-driving used in the optical pickup of an optical disk drive. The device comprises an objective lens holder for holding an objective lens, a sheet coil, and a counterbalance mounted on the opposite side of the objective lens. The sheet coil comprises an insulating sheet on which focusing helical coil patterns and tracking helical coil patterns are juxtaposed. The holder has sheet-holding portions of an arc-shaped cross section. The focusing and tracking coil patterns are formed on the curved surfaces of the sheet-holding portions. Focusing magnets are mounted opposite to the focusing coil patterns. Tracking magnets are mounted opposite to the tracking coil patterns.