Abstract: According to an automatic attitude correcting system of this invention, correction signals which are used to reduce control errors through a focus control, a tracking control, a tilt control, etc. are determined by measuring the amplitude of an RF reproduction signal reproduced from an optical disc at a predetermined area. For setting a correction signal value to be supplied to an attitude control mechanism such as an attitude control mechanism, a scanning signal whose signal level varies with time variation is supplied to a control mechanism driving circuit. The scanning signal varies in level at every one-revolution of the optical disc, and the amplitude of the RF reproduction signal is outputted from the optical head at every one-revolution of the optical disc, and measured at a predetermined angle for each level of the scanning signal.

Abstract: A recording head Hw1 records a record signal including a data region, a pilot signal region, and a mask region with a width of 3 Tp. A recording head Hw2 overwrites the record region of the head Hw1 with another data. Since the recorded signal includes the mask region, the pilot signal region recorded by the head Hw1 is not erased. The recording head Hw1 overwrites with a record signal. At this point, since the recorded signal contains a mask region, the former pilot signal region is not erased. Instead, a new pilot signal region is formed. By repeating these operations, pilot signal regions are adjacently formed at track edges of a track corresponding to the recording head Hw1. Since the pilot signal is reproduced by a reproducing head with the same azimuth as the recording head, the pilot signal with a short wavelength can be used.

Abstract: In a magnetic head drive for a magnetic tape recorder of a helical scan system, a pair of first and second longitudinal bimorph elements fixed to a support member is connected to a flexible bridge member and a magnetic head is mounted to the bridge member. A pair of first and second electric sources supply electric voltages independently to electrodes of the first and second bimorph elements. The voltages applied to the bimorphs are controlled against a deviation from a record track in a magnetic tape to keep a protrusion quantity of the magnetic head constant for automatic tracking. In a magnetic tape recorder wherein the upper and lower drums of a rotating head scanner are fixed and the magnetic head is rotated along an elliptical orbit, the two bimorphs are controlled not only against a deviation from a record track in a magnetic tape but also to a rotation angle of the magnetic head in order to keep a protrusion quantity of the magnetic head constant.

Abstract: For disk drives having dual element heads, an invention for providing self-calibration of hard-disk writer elements to reader elements offsets. A method is provided for positioning a reader element for reading information on a disk, and from the information read, determining a reference line for the writer element. The method may be incorporated into a hard-disk in the form of a self-calibration routine in memory. The self-calibration routine may be used for computing offsets for separate writer/reader elements in a dual head assembly. Also, apparatus are provided for self-calibration of hard-disk writer to reader element offsets.

Abstract: A method and tape recorder apparatus are disclosed for recording a signal on a tape. The tape recorder apparatus is provided with a memory for storing a signal to be recorded on a tape. The tape recorder apparatus has a recording head for recording the signal stored in the memory. The tape recorder apparatus also has a playback head for reproducing the signal recorded by the recording head on the tape. Furthermore, the tape recorder apparatus has a comparison circuit for comparing the signal reproduced by the playback head with the signal stored in the memory. Depending on errors identified by the comparison circuit in the reproduced signal, the signal in the memory is re-recorded on the tape.

Abstract: In a magnetic recording/playback apparatus for recording and playing back a digital video signal on a helical track of a magnetic tape using two or more rotary heads, the playback image at the time of high-speed playback is improved by setting the tape travel speed at the time of high-speed playback at an even multiple of a normal playback speed. Further a tracking phase is offset by one half the track pitch with respect to the tracking during normal speed playback. Alternatively, essential information of the information having been high-efficiency coded is recorded in the central part, and near the ends of the tracks, while high-precision information is recorded in intermediate parts intermediate between the central part and the parts near the ends. Still alternatively, the video data of one of the consecutive fields is recorded in the central part of the tracks and the video data of the other of the consecutive fields is recorded near the ends of the tracks.

Abstract: A spindle sync control system for a plurality of magnetic disk drives connected in parallel to a host computer. The system is capable of reducing lost time and preventing a system from going down. The system includes a discriminator (25A) for discriminating the presence or absence of a reference index, a medium index and a Hall index; an offset calculator (25B) for calculating an offset value between the medium, index and Hall index before starting spindle sync control; a memory means (26) for storing the thus calculated offset value; a phase difference calculator means (25C) for calculating a phase difference between the reference index and the medium index; and a determination means (25D) for determining a driving control value for rotating a spindle motor (7) according to the thus calculated phase difference.

Abstract: An optical recording/reproducing apparatus including an optical recording medium having an alternating area in which information may be recorded instead of the normal recording area when the information fails to be recorded in the normal recording area, and a plurality of control regions in which position information of the recording area having failed to record information and position information of the alternating area in which the information failed to be recorded is recorded instead of the recording area. The apparatus records the information in a predetermined information recording area of the optical recording area, reproduces the predetermined information, collates the information intended to be recorded with the reproduced predetermined information, and judges that the predetermined information was not correctly recorded in the predetermined recording area.

Abstract: An optical disc includes a signal recording track spirally formed on the surface of the optical disc, information pits formed on the signal recording track, and a plurality of non-signal regions periodically formed on the signal recording track, wherein no information pit is formed on the non-signal region.

Abstract: A magnetic recording and reproducing device and a magnetic tape library device are provided for properly recovering a function and issuing a warning when a failure of a magnetic head of the device takes place because of wear and dirt of the magnetic head. Further, a method for maintaining the magnetic head is provided. A wear sensor and a dirt sensor are prepared for sensing a wear amount of a state of dirt of the magnetic head. A head check controller operates to determine the wear amount of the magnetic head and the state of dirt based on the sensed result. In accordance with the determined result, the warning device is started for taking a precaution of preventing a head failure. As one aspect, the tape library device instructs to load the cleaning tape using a robot.

Abstract: A velocity detection circuit which detects the velocity of movement of an optical head. The velocity detection circuit includes an edge detection circuit for detecting an edge of a position detection signal and outputting an edge signal, a divider for dividing a clock signal of a predetermined period, a first binary counter and a first D-type flipflop for counting the number of pulses of the divided clock signal within an interval from an edge signal to a next edge signal to calculate time data, a second binary counter for counting the clock signal, a comparator for outputting, when the time data outputted from the first D-type flipflop and the data counted by the second binary counter coincide with each other, a pulse (reference signal) to be used to reset the count data of the second binary counter, and a third binary counter and a second D-type flipflop for counting the number of pulses of the comparison signal based on a sampling signal generated at fixed time intervals to calculate velocity data.

Abstract: Write precompensation optimization for a partial response maximum likelihood ("PRML") magnetic recording channel adapted to a mass production environment. Optimal write precompensation may be determined by writing a tribit data pattern known to produce worst case nonlinear transition shift ("NLTS") onto a magnetic recording medium; reading back the recorded data pattern; and calculating the mean-squared error ("MSE") for one or more of the equalized data sample levels associated with the PRML channel to be optimized. The writing and reading back process is repeated with varying amounts of precompensation applied to the written pattern. The optimal amount of write precompensation is determined either by minimizing the MSE for a selected sample level or by minimizing MSE between the middle and the upper or lower of the ternary PRML sample levels.

Abstract: In a method of recording digital information signals to form tracks on a magnetic tape, the samples of the signals to be recorded are divided into a plurality of odd sample groups and a plurality of even samples groups. The groups containing adjacent samples are disposed on differently-numbered regions of different tracks. Error correcting codeword may be recorded in a plurality of tracks. Errors in one region can be corrected or compensated by samples in different tracks or samples in differently-numbered regions.

Abstract: In an information recording/reproducing apparatus constructed of: a buffer for storing therein consecutive recording data in a unit of two dimensional conversion; a coding device for converting the consecutive recording data into a two-dimensional data arrangement arranged by "n" lines and "m" columns corresponding to said unit of data; a recording device for subdividing said two-dimensional data arrangement arranged by "n" lines and "m" columns so as to be read out, and for controlling "m" pieces of light sources in accordance with these data series; and an optical apparatus for converging luminous fluxes from said "m" pieces of light sources so as to form "m" pieces of spots on a disk plane, the recording data is recorded on the disk plane as an optically distringuishable pit group having two-dimensionally extended areas arranged by "n" lines and "m" columns.

Abstract: A signal reproducing apparatus, which reproduces data from a tape in which data and a pilot signal for tracking have been recorded In oblique tracks, includes a tape driver for running the tape in the longitudinal direction, a rotary head for rotating and scanning the tape to produce reproduction signals, a reference generator for generating a reference signal which Is the rotation standard of the rotary head, a tracking error detector for producing a tracking error signal from the pilot signal contained in the reproduction signals, and a timing controller for controlling the start timing of tape running of the tape driver with respect to the reference signal, on the basis of the tracking error signal and reference signal in the stopped state of tape running.

Abstract: For the clock extraction from n digital signals read from each of n tracks there are provided n phase-locked loops. In order to compensate for speed variations in the speed of transport of the record carrier there is provided an additional frequency control system. This system derives a control signal which is a measure of the speed variations, which control signal is applied to the voltage-controlled oscillators of all the phase-locked loops as a common control signal.

Abstract: Recording areas for tracking on which specific servo patterns are recorded are provided preceding data tracks on which data is to be recorded on a recording tape scanned by a helical scan system. The data tracks and recording areas for tracking are recorded at different azimuths. At the time of a playback operation, etc., the specific patterns in the recording areas for tracking are played back by the helical scan system and tracking is performed by using the playback timing.

Abstract: In an optical recording method and apparatus, the intensity of a laser beam to be radiated onto a magnetooptical recording medium is raised from an intensity P.sub.pre for maintaining a pre-heat state, in which the temperature on the medium surface has a predetermined temperature .THETA..sub.pre, to an intensity P.sub.W1 higher than P.sub.pre so as to form a mark on the medium, the intensity is reduced to an intensity P.sub.LB lower than P.sub.pre, and after an elapse of a time T.sub.off, the intensity is raised to P.sub.pre. At least one of P.sub.pre, T.sub.off, and P.sub.LB is controlled to achieve the pre-heat state within a time period until the intensity is raised to P.sub.W1 again to form the next mark.

Abstract: A digital signal reproducing circuit for reproducing a digital signal recorded on a recording medium, includes: an equalizing circuit for receiving a reproduced RF signal and varying at least one of gain characteristics and phase characteristics thereof with a control signal; a Viterbi decoder for receiving the output signal of the equalizing circuit; and a control unit for generating a control signal for the equalizer, wherein the control unit is adapted to control the equalizer so as to minimize a metric increasing amount of the Viterbi decoder.

Abstract: An optical data storage system comprises a multiple data surface medium and optical head. The medium comprises a plurality of substrates separated by a light transmissive medium. Data surfaces are located on the substrate surfaces which lie adjacent a light transmissive medium. The data surfaces are substantially light transmissive. The optical head includes an aberration compensator to allow the head to focus onto the different data surfaces and a filter to screen out unwanted reflected light.