Abstract: A recording method and apparatus for an optical disk employs a data format having a fixed pattern sync portion in which a minimum run length of zeros and a maximum run length of zeros are not adjacent to each other. As such, temperature difference caused during recording the optical disk may be made smaller thermal stress applied upon the medium may be reduced, the deterioration thereof may be restrained, and the repetitive frequency of the medium may be improved.

Abstract: An objective lens driving apparatus for an optical pick-up, in which an objective lens is loaded on a driving body which is driven in a horizontal and a vertical direction and an objective lens driving portion is supported by four elastic linear members, includes two supports having two penetration holes each through which two pairs of elastic linear members pass, wherein the objective lens driving body is connected to the two pairs of elastic linear members, so as to prevent the driving body from rolling.

Abstract: A galvanomirror unit including a housing, a yoke supporting a galvanomirror to adjust the angular position thereof, and a retainer secured to the housing. The galvanomirror unit further includes an initial position adjusting mechanism provided between the yoke and the retainer to support the yoke, so as to adjust the angular position thereof in the vertical and horizontal directions, with respect to the retainer.

Abstract: This invention is an improved digital data storage magnetic tape transport servo-control system comprising a tape supply reel and supply reel motor, a tension transducer, a head drum having at least one read/write head secured thereto and coupled to a head drum motor, a capstan and a capstan motor, a pinch roller, a take-up reel and a take-up reel motor. A processor provides programmable digital control signals to and responsive to signals from the supply reel, the supply reel motor, the tension transducer, the head drum, the head drum motor, the capstan, the capstan motor, the take-up reel, and the take-up reel motor. The processor controls tape tension in cooperation with the supply reel motor and the tension transducer, controls tape speed in cooperation with the capstan and the capstan motor, controls take-up reel torque in cooperation with the take-up reel and the take-up reel motor, and controls head drum speed in cooperation with the head drum and the head drum motor.

Abstract: In a record/reproduce apparatus, medium defects in magnetic disks are avoided without considerably losing record areas. In a record or reproduce mode, the plurality of magnetic disks are accessed in parallel by a plurality of magnetic heads and a plurality of record circuits or reproduce circuits. Regarding the record areas where only one of the magnetic disks has the medium defect, a control circuit controls a head change-over circuit so that a record area in a spare magnetic disk may be accessed by a spare magnetic head instead of the defective record area. Besides, regarding the record areas where two or more of the magnetic disks have the medium defects, the control circuit operates so that spare record areas in the two or more magnetic disks may be accessed instead of the defective record areas.

Abstract: An optical magnetic disk recording/reproducing apparatus is capable of reproducing address data when recording data signals on a magneto-optical disk and when deleting data signals from a magneto-optical disk. The reproduction of address data is performed with a high degree of stability. The apparatus includes an optical head, photoelectric voltage converters, various adders, a differential device and several switches. A first switch switches between a first position in which an output of the first switch is connected to the output of the differential device and a second position in which the output of the first switch is connected to a reference voltage. A second switch includes a first position in which an output of the second switch is connected to the output of one of the adders and a second position in which an output of the second switch is connected to the output of the first switch. Several control signal generators control the switches.

Abstract: An apparatus for controlling rotation of a spindle motor includes a lock detection unit, a memory unit, a comparison unit, and a control unit. When the lock detection unit detects the lock state of the time base servo loop, a voltage corresponding to the frequency of a read RF signal is stored in the memory unit. When the control unit detects that the rotation velocity of the spindle motor greatly deviates from a normal rotation velocity, it effects a control so as to accelerate or decelerate the spindle motor in dependency upon a compared result of the comparison unit which makes a comparison between a voltage corresponding to the frequency of the read RF signal and a voltage stored in the memory unit.

Abstract: A tracking error detecting circuit in which tracking error detecting pilot signals having different frequencies are added to a main signal every track and recorded onto a magnetic recording medium, and upon reproduction, reproduction output levels of the pilot signals reproduced as crosstalks from both of adjacent tracks are compared, and a tracking error is detected. n signals having the same frequencies as those of the pilot signals and whose phases are different are generated and multiplied to the reproduction signal. Unnecessary components are eliminated by n LPFs (Lowpass filters). The amplitude values of the reproduced pilot signals are vector separated and detected. Further, the vector separated amplitude values are vector synthesized and detected. Therefore, by multiplying the signals having the same frequencies as those of the pilot signals, the synchronous detection is performed.

Abstract: An apparatus for phase correction of clock signal used for data reproduction employs reference clock signals recorded with the data to select the optimum phase increment for outside clock signals generated from preformed patterns on the recording medium. An apparatus for data reproduction compares recorded data sampled using outside clock signals phase corrected by the optimum phase increment with a threshold based on the reference clock signals to reproduce the recorded data with a high noise margin.