Abstract: The relative tilt of an optical disk and a movable objective lens holder is measured as an output of a differential amplifier which subtracts an output of first photodetectors and which detect the reflected light from optical disk from an output of second photodetectors and which detect the reflected light from a reflector mounted on movable objective lens holder. The signal from differential amplifier is used to tilt movable objective lens holder so that the movable objective lens holder compensates the tilt of optical disk.

Abstract: Methods of and information recording devices for recording and/or inhibiting recording of a signal including copy bits on a record carrier, and a record carrier including that signal. The signal has successive information frames including main data and subcode data. The subcode data of the information frames make up successive subcode frames having copy bits with logic values which alternate among the subcode frames in accordance with a predetermined pattern. Each subcode frame has at least one copy bit. In one of the embodiments, the signal is received and a determination is made whether to inhibit its recording on the basis of the predetermined pattern exhibited by the logic values of the copy bits contained in the subcode frames. In another embodiment the subcode frames are replaced by substitute subcode frames having copy bits with logic values which alternate among the substitute subcode frames in accordance with a selected pattern prior to recording of the signal.

Abstract: An apparatus for compensating a track when a track crossing signal is not generated due to an offset detection flag (ODF) region or a defect of a disk, comprises a missed track compensating processor for compensating a missed track signal generated when the light beam passes through the ODF region, and a track counter for mixing a pulse signal of a monostable multivibrator with a compensation signal output from the missed track compensation processor and counting the number of tracks. Thus, the missed track signal which is generated due to the ODF region and disk defects is compensated, thereby accurately counting the number of tracks over which the light beam cross.

Abstract: In an optical disk recorder, during the sensing of closely-spaced, position-indicating, machine-sensible indicia, a first peak of a track error signal is detected. In response to the first peak being detected, a half-track counter is decremented from a value which depends upon the position of the destination track relative to a current track. In response to the occurrence of a selected value of the half-track counter and the presence of a zero crossing of the tracking error signal, a first timer is activated to mask any defects occurring during the selected first half cycle of the last cycle of the tracking error signal. The half-track counter is again decremented in response to a second peak being detected and the occurrence of a next-to-last zero crossing of the tracking error signal and a second timer is then activated to mask any subsequent defects occurring during the second half cycle of the tracking error signal.

Abstract: A two channel circuit and method for the automatic edit optimization of a recording medium which is operable with a recorder such as a video tape recorder or a disc recorder, utilizes a first channel means including an automatic scan tracking playback head and a second channel means including a record head. First and second rf peak signals indicative of variations in the stored data patterns in the medium are generated for the two channels. The gain of a variable gain amplifier coupled to the automatic scan tracking playback head is adjusted in accordance with a first correction signal derived from the generated first rf peak signal. The gain of a variable gain amplifier coupled to the record head is adjusted in accordance with a second correction signal derived from the generated second rf peak signal.

Abstract: In a magnetic recording and reproducing apparatus such as DAT, when recording an acoustic signal which is a series of recording information on a magnetic tape, a program start signal is recorded automatically at the start of recording. This program start signal indicates a program recording start position on an acoustic signal or the like. This program start signal can be additionally recorded in a magnetic tape in which a program has been already recorded. When the program start signal record button is pressed while reproducing the magnetic tape, plural recording areas including the recording area which has been reproduced at the time of pressing are reproduced repeatedly. A recording area to be recorded additionally may be arbitrarily specified in such plural recording areas being reproduced repeatedly. The front-rear relation of the specified recording area may be confirmed by lighting an indicator or by the change of reproduction level during repetitive reproduction action.

Abstract: A disc-shaped recording medium in which concentric recording tracks or a spiral recording track is divided circumferentially to form a number of sectors in each of which track addresses are pre-recorded, wherein each position of the track address is formed by a base-m Gray code, and wherein each position is sequentially formed so that the Gray code of positive or negative logic and a negative logic is used for the upper order digit having the value of an even or odd number and the upper order digit having the value of an odd number, respectively.

Abstract: A single channel circuit and method for the automatic edit optimization of a recording medium which is operable with a recorder such as a video tape recorder or a disc recorder utilizes the difference between signal outputs from an automatic scan tracking playback head and a record, head to provide a difference signal indicative of the rf amplitude fluctuations caused by scene or data pattern variations of the data stored on the recording medium. A correction signal corresponding to the difference signal is stored, and used as a feedback signal to normalize the gain of a variable gain amplifier. The single channel is switched at a predetermined rate between circuitry coupled to the automatic scan tracking playback head and circuitry coupled to the record head in order to obtain rf amplitude samples from both heads to develop the correction signal. Thereby, the correction signal allows a precise edit optimize so that a subsequent edit operation such as an insert edit can be precisely performed.

Abstract: An electromagnetic objective lens driving apparatus of an optical disc data recording and reproducing apparatus includes a carriage which is movable in a radial direction of an optical disc, and an objective lens holder which supports an objective lens in a manner such that laser beams are converged onto the optical disc. The objective lens holder is supported on the carriage so as to move in the focusing and the tracking directions of the optical disc. The objective lens holder is provided with a cylindrical holder portion which holds the objective lens, and a pair of symmetrical wings that project radially from the cylindrical holder portion in the tracking direction.

Abstract: A scanning device for recording/reading data in data tracks of a recording medium includes a light source supported by a tracking head for guiding a light beam along the data tracks. The data tracks are rotated and the beam is focussed onto the data tracks. The light source is moved at an angle .alpha. with respect to the radial direction of motion of the data tracks. An optical element directs the light beam to the recording medium and directs light reflected from the recording medium to a detector. An astimatic element is arranged between the optical element and the detector. The scanning device is improved in that the astimatic element has one axis arranged at the angle .alpha. with respect to the radial direction of motion.

Abstract: Disclosed is a device for access to and follower control of a track of an optical disk. This device has an optical head with an axis orthogonal to the plane of the disk, at least one fixed magnetic circuit comprising a core that is secant with all the turns of the track, the gap of which forms a plane that is substantially perpendicular to the support, a first motor device allowing for the access to and radial tracking of the track formed by at least one first coil mounted so that it moves on the core of the magnetic circuit and a second motor device that enables the focusing of the radiation on the track consisting of a second coil cooperating with a magnetic circuit. The optical head, the coil of the first motor device and the coil of the second motor device are rigidly fixed to one another so as to form a single compact moving element that moves in the gaps of the magnetic circuits. The disclosed device can be applied to digital optical disks.

Abstract: A head control apparatus of the invention includes a moving unit for moving an optical head to a given information track on an optical disk having concentric information tracks, a detector for detecting a direction of movement of the optical head from the a signal reproduced from the optical head, and a controller that, when the detector has detected the direction of movement of the optical head, controls the moving unit so that the optical head may move to a specified information track at a first speed, and that, when the detector has not detected the direction of movement the optical head, controls the moving unit so that the optical head may move to a specified information track at a second speed slower than the first speed.

Abstract: A recording/reproducing optical head capable of causing a light spot on a photodetector for detecting a focusing error signal to stand still without being affected by variations in wavelength of light used, capable of adjusting a tracking error signal independently of the focusing error signal, and capable of utilizing light having an order of diffraction of -1 for the purpose of detecting a signal, in which a cylindrical lens for generating astigmatism and a diffraction grating made up of two regions different in the direction of diffraction or the angle of diffraction from each other are interposed between a beam splitter and a photodetector, a light beam diffracted from the diffraction grating and including the diffracted light of the zero-th order (that is, light which has passed through the diffraction grating without being deflected) is received by the photodetector, the diffracted light of the zero-th order is used for detecting a focusing error signal according to the astigmatism method, and diffracte

Abstract: In an optical recording medium of the present invention, a plurality of tracks each extending in a first direction are arranged in a second direction which is different from the first direction in such a manner that the plurality of tracks are apart from one another along the second direction with a track-track between area being formed between each two tracks adjacent to each other. In the optical recording medium, at least one wobbling pit is formed in a track-track between area positioned between each two tracks. The wobbling pit is adapted for tracking operations for both the each two adjacent tracks. In order to discriminate between one track and the other track of the each two adjacent tracks, the optical recording medium is provided with a disrcimination pit, or the wobbling pits are arranged so that the number, position or dimension of the wobbling pit provided on a track-track between area may be changed.

Abstract: In an optical head which comprises a focusing unit section for moving an objective lens, used to focus a light beam on a recording medium, in a direction perpendicular to the recording medium, and a tracking unit section for moving the focusing unit section in a direction perpendicular to an information track on the recording medium, a lens holder for supporting the objective lens is fixed to two leaf springs, and a carriage body is disposed between the two leaf springs. The leaf springs and the central portion of a tracking coil are fixed to the carriage body. The tracking coil has stepped portions at its central portion, and its whole structure except the central portion is flat.

Abstract: A recording/reproducing apparatus for recording/reproducing data by relatively moving either of an optical card and optical head wherein, in order that data may be recorded/reproduced on the optical card by moving either of the optical head and optical card, during an access operation to gain access to reach a target track, such data process as adding data for detecting and correcting errors to data to be recorded in the optical card by a data encoding circuit or correcting errors on data already read out by an error correcting circuit is made in parallel. The data are also transferred during the access operation.

Abstract: An information signal reproducing circuit for use in an optical information recording/reproducing apparatus, includes a photo detector, a plurality of amplifiers and a plurality of couplings for connecting the amplifiers to each other in a serial manner. A gain of a signal produced by the photo detector is decreased only for a time period during which information is recorded or erased in the information recording/reproducing apparatus. Therefore, in case the amplifiers are serially connected to each other by means of AC couplings, information signal can be correctly read out without being influenced by transients of capacitors constituted of the AC couplings. In case the amplifiers are serially connected to each other by means of DC couplings, information signal can be correctly read out without causing a latch up.

Abstract: A method of aligning a multiple transducer magnetic head with respect to a magnetic recording tape. Values related to the offset of each transducer from a reference location are determined, using reference signals on the tape. From these values the amount of compensation required to accurately position any particular transducer with respect to any track can be calculated. By a preferred selection of the reference for one such offset value, and by taking known design of the head into account, simplified processing of the values is possible.

Abstract: The present invention aims at preventing erroneous data reproduction even when the amplitude center of a signal of a data part read out from an optical disc is displaced. An information reproducing apparatus comprises read means for reading data stored in each of block units on an optical disc and outputting a read signal, digitizing means for digitizing the read signal by using a slice level, generating means for comparing the signal digitized by the digitizing means and clock signals output at predetermined intervals, thereby generating a charge width signal representing a phase difference between the digitized signal and the clock signals, while the data stored in a data storing portion of the block unit is read by the read means, and changing means for changing the slice level of the digitizing means on the basis of the charge width signal generated by the generating means.

Abstract: In recording data on a disk-shaped information recording medium having formed thereon a plurality of concentric or spiral tracks each being divided into a plurality of sectors each having an ID field and a data field, a data mark is selected from a plurality of distinct data marks according to an address of a target sector such that the selected data mark is different from a data mark recorded in an adjacent sector which is contained in an adjacent track. The selected data mark is recorded at the start position of the data field of the target sector. In reproducing the recorded data, a data mark is selected from the plurality of distinct data marks according to an address of a target sector, and is compared with a data mark reproduced from the target sector to detect whether the reproduced data mark coincides with the selected data mark. Sector data in the target sector is reproduced only when the reproduced data mark coincides with the selected data mark.