Abstract: Method of recording on a record medium by receiving a series of data elements, adding error detection and error correction data to each data element, moving some of the data in each data element to an adjacent data element to produce arranged data elements, and recording the arranged data elements in different sectors on a record medium. Upon reproduction of the arranged data elements from a record medium, some of the data in each arranged data element are moved to an adjacent data element to produce rearranged data elements. Errors in each rearranged data element are detected and corrected using data contained therein. A record medium having concentric tracks on which a plurality of sectors are located stores data in each of the sectors. The data in each sector pertains to two different sectors so that the affect of a burst error on a particular sector is minimized.

Abstract: In a disc recording method in which a disc on which servo control data is recorded in advance in alignment with a radial direction is divided into a plurality of zones in the radial direction and digital data having different clock rates are recorded on every zone, reference data for detecting the quality of a recording signal is recorded on a whole recording data area of one segment segmented by at least said servo control data. Therefore, the reproduction of data recorded in the zone-recording fashion can be controlled with ease in any zone.

Abstract: In an optical recording medium on which the main information is recorded on a pre-formed recording track along the track direction and in which the recorded data are read out by optical means, frame sync signals based on the same format as the format for the main information are pre-recorded by offsetting the recording track itself along its width for each frame as an information recording unit, for facilitating frame synchronization and simplifying the construction through the use of a sole common synchronizing circuit. The information pre-recorded by offsetting the track itself along its width includes not only the frame sync signals but also any reproduce-only information for increasing the disc recording capacity.

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: An optical storage medium provided with both a read-write area in which read-write data can be rewritably stored and a read-only area in which read-write data is previously stored in an unerasable manner. In the read-write area, a guide track is previously formed for tracking control, and read-write data is rewritably stored, for example photomagnetically, along the guide track. In the read-only area, data is stored along a read-only track that is offset over a portion of its length in a direction lateral to the track direction to represent the read-only data. This read-only data may be reproduced by detecting the laser light radiated from an optical pickup and reflected by the medium by a two-segment photodetector.

Abstract: A magneto-optical recording and reproducing system in a magneto-optical disk capable of being overwrite recorded by applying a magnetic field to a photo-sensitive recording layer and irradiating a laser beam onto the recording layer. A track pitch and a diameter of the laser beam are set so that recording tracks to be formed by irradiation of the laser beam overlap, each other between adjacent tracks. Accordingly, data recording density of the magneto-optical disk, especially in a radial direction thereof, can be increased.

Abstract: In an optical recording medium on which the main information is recorded on a pre-formed recording track along the track direction and in which the recorded data are read out by opticaL means, frame sync signals based on the same format as the format for the main information are pre-recorded by offsetting the recording track itself along its width for each frame as an information recording unit, for facilitating frame synchronization and simplifying the construction through the use of a sole common synchronizing circuit. The information pre-recorded by offsetting the track itself along its width includes not only the frame sync signals but also any reproduce-only information for increasing the disc recording capacity.

Abstract: A recording and/or reproducing device for detecting the servo pattern pre-recorded at a pre-set, interval on a disc-shaped recording medium, and for generating channel clocks, that is, clock signals for sampling data used during recording or reproduction on the basis of the detected information on the servo pattern, is disclosed. For providing the correctly phased channel clocks, a voltage controlled oscillator employed in the phase-locked loop of a channel clock forming unit, of the recording and/or reproducing device for generating the channel clocks is controlled not only by phase error data but also by positive phase error data and negative phase error data for enlarging the locking range for enabling correct phase locking.

Abstract: A magneto-optic disk apparatus is disclosed which can reproduce data well from a magneto-optic disk on which the data are reproduced in a high density with an increased line density. Recording data are converted into NRZI data by a pre-encoder and recorded onto a magneto-optic disk using a magnetic field modulating method while irradiating a laser beam intermittently upon the disk. A reproduced radio frequency signal from the disk is clamped for each segment by a clamp circuit, converted into a digital signal by an analog to digital converter, waveform equalized by an equalizer so that it may be approximated to the waveform of a cosine filter suitable for partial response PR(1, 1), and supplied to a data detection circuit. The data detection circuit detects data using the viterbi algorithm to obtain reproduced data in the form of NRZ data.

Abstract: A method of recording information is provided, in which a first signal is recorded along the length of a recording track previously formed on a recording medium. On the recording track, a second signal is prerecorded by offsetting the track along its width. During the recording of the first signal, the points of transition of the first signal are positioned so as to be spaced apart from, and therefore unaffected by, the points of transition of the second signal. Also, by including a clock synchronization signal in the first signal, PLL capture may be achieved accurately in a shorter time. In addition, the unit of phase shift between the channel clock of the first signal and the channel clock of the second signal is set to be shorter than the channel clock bit. A data recording method and an optical data recording method are also provided, which may be suitably applied to a magneto-optical disc or the like.

Abstract: The present invention is concerned with a recording medium wherein, in a recording medium in which the information may be regenerated optically, a track is pre-recorded or pre-formatted by being deviated along the track width with a signal which the baseband signal of a read-only information signal freed of high-frequency components. The present invention is also concerned with a recording apparatus for forming a track of an optical recording medium from which an information can be reproduced optically, wherein the apparatus includes a deviating device for deviating a track-forming recording beam along the width of the track of the optical recording medium, a deviation control signal generating device for generating deviation control baseband signals for controlling the deviation device, and a low-pass filter for eliminating the high-frequency components of the deviation control baseband signals.

Abstract: A magneto-optical pickup apparatus includes an objective lens for focusing a laser beam emitted from a laser device onto a magneto-optical recording medium, driving coils, on which the objective lens is mounted, for driving the objective lens in focusing and tracking directions, and a plate arranged at an end portion of the driving coils between the objective lens and the magneto-optical recording medium. The plate is formed with a coil pattern for generating a magnetic field to be applied to the magneto-optical recording medium, and can allow a laser beam transmitted through the objective lens to pass therethrough.

Abstract: A method of recording user data on a DC-RAM disc medium comprising the steps of recording servo signals in a pair of spaced apart servo areas in each one of a predetermined number of segments which form a predetermined number of sectors of each one of a plurality of recording tracks on the disc medium, and recording along a portion of each track, between each servo area, units of 12 bytes of user data and 4 bytes of parities for the user data so that among the predetermined number of segments are a plurality of user data segments each consisting of a servo signal and one or more units of 12 bytes of user data and the parities for the 12 bytes of user data.

Abstract: This invention relates to a digital modulating method used for recording a PCM audio signal, computer data, and etc. on a recording medium such as an optical disc. The digital modulating method is constructed so that the minimum length between transition could be the maximum in encoding M bits into N bits (M<N), and can generate clock pulses with a simple circuit arrangement by satisfying the relationship N=.alpha.M, where .alpha. is an integer equal to or larger than 2.Further, by converting a predetermined unit of input data into a first code signal according to substantially the same conversion rule and selectively adding coupling bits of different bit number to each junction between a first code signal and an adjacent code signal, the digital modulating method is adaptable for various transmission systems with a simple arrangement.

Abstract: In a recording apparatus employing a magneto-optical effect, and in which a light beam irradiates a region of a magneto-optical disc while a magnetic field acts on the disc at such region and is modulated by coded data in accordance with a predetermined modulation system; the light beam is intermittently energized by drive pulses, and the energizing of the light beam is inhibited at times corresponding to transitions in the coded data when the ratio Tmin/Tw is greater than 1, in which Tmin is the minimum length between transitions in the coded data and Tw is a window margin for the modulation system employed for modulating the magnetic field.

Abstract: In a magneto-optical signal reproducing apparatus for reading out a signal recorded on a magneto-optical recording medium by an optical pickup device so as to provide a magneto-optical signal which, in turn, is level-discriminated on the basis of a reference level to reproduce data therefrom, the reference level is controlled in accordance with a level of an in-phase signal component provided from the optical pickup device, thereby enabling stable data reproduction.

Abstract: A recording medium in which one sector is divided into a plurality of segments and information is recorded in the segments, uses a reproducing method in which information is reproduced optically from this medium. The recording medium has an area in which no embossed pit is formed beforehand comprising at least one segment among a plurality of segments, and embossed pits indicative of the head of the sector which is formed in correspondence to the head position of the sector. Clocks are reproduced by detecting the pit for clock reproduction on the basis of the area in the recording medium in which no embossed pit is formed beforehand. The head position of the sector is detected by detecting whether the pit indicative of the head of the sector is present or not at a timing based on the clock. With this method, the head position of the sector can be detected correctly even if information was recorded by a modulating system in which all signal patterns can exist according to the modulating rule.

Abstract: This invention relates to a code modulating apparatus and a code demodulating apparatus for digital signals such as PCM audio signal, computer data, and so on. An input signal of M bit words is divided into a plurality of data bits and the code conversion is performed for respective data bits, thereby simplifying the circuit arrangement for data conversion.

Abstract: An optical recording medium for storing optically readable data includes at least one preformed recording track of predetermined width and extending in a predetermined recording direction, the recording track having a recordable region extending in the recording direction thereof for recording data containing clock signal components, the recording track being provided with predetermined offset portions extending in the direction of the width thereof representing offset recorded data, the offset portions being formed such that the offset recorded data has a frequency upon scanning the recording track related by an integral ratio with respect to the clock signal components of the data.

Abstract: A record medium having a pre-formed recording track with a recordable area on the recording track in which data is recorded and an area on the recording track used exclusively for reproduction in which data is pre-recorded by displacing the track in the track width direction and in which the track width of the data recordable area is wider than that of the area used exclusively for reproduction, so that crosstalk is minimized and the carrier-to-noise ratio and error rate when reproducing recorded data are improved.