Abstract: An actuator including at least one moving body, at least one fixed body and a connecting member is provided. The moving body is suitable for moving along a direction, and includes at least one coil. In addition, the fixed body includes a permanent magnet and a yoke, wherein the coil is disposed between the permanent magnet and the yoke, and the polarity direction of the permanent magnet is parallel to the moving direction of the moving body. Furthermore, the connecting member is used for connecting the moving body and the fixed body. The actuator meets the requirements of miniaturization, low power consumption and low cost.

Abstract: A disk drive is disclosed comprising a disk for storing data, the disk comprising a public area for storing plaintext data and a pristine area for storing encrypted data. The disk drive comprises a head for reading the encrypted data from the pristine area of the disk, and a control system for controlling access to the pristine area of the disk. Authentication circuitry within the disk drive is provided for authenticating a request received from an external entity to access the pristine area of the disk and for enabling the control system if the request is authenticated. The disk drive further comprises a secret drive key, and decryption circuitry responsive to the secret drive key, for decrypting the encrypted data stored in the pristine area of the disk.

Abstract: An optical disk provided with read-exclusive regions where previously recorded information can be read, and with write-enable regions where information can be written. Information not desired to be rewritten can be recorded on the read-exclusive regions. The write-enable regions are open to users to freely add information thereto and to re-write information recorded. This optical disk can thus be used in various fields.

Abstract: An optical disk recording/reproducing device for recording or reproducing information on or from an optical disk while rotatively driving the optical disk at a constant angular velocity. The disk has pre-recorded information cyclically formed along a track so as to provide rotation control at a constant linear velocity. The device, which includes a clock generating circuit for generating a clock signal for recording or reproducing in accordance with a recording frequency of the pre-recorded information derived from signals reproduced by an optical head, is designed to perform recording or reproducing operations with a recording frequency according to the clock signal. The device further includes a magnetic filed control circuit and a recording light power control circuit whereby a magnetic field and light power to be applied to the optical disk is varied according to the recording frequency during recording operations.

Abstract: A video disc player and the method of its operation are such that in a so-called scan playback mode a track jump is completed at the center of eccentricity of the track on the optical video disc so that various characteristics relating to timebase correction are improved.

Abstract: There is disclosed an information recording device composed of a memory for storing an original signal from a plurality of adjacent tracks, and a computational circuit for generating an inverse number component of a crosstalk component which is considered to be mixed in during a reproduction process on the basis of storage data from the memory to provide an actual recording signal as a product of the inverse number component and the original signal to record the actual recording signal onto the recording medium, thereby canceling a crosstalk component produced at the time of reading by the inverse number component of the crosstalk component included in the actual recording signal when the actual recording signal has been read.

Abstract: A control system is provided for an optical disk driving apparatus adapted to rotate an optical disk having a plurality of tracks, and which is adapted, during the rotation of the disk, to perform optical recording and/or reproduction of information for a track which has been accessed with a light beam. The control system changes the speed f of recording/reproduction of information in accordance with the radius r of a track to be accessed in such a manner that the tracks are divided into a plurality of concentric annular blocks each having different approximate radii, and the same speed f of the recording/reproduction of information is allocated to the tracks in the same block but different speeds f of recording and/or reproduction of information are allocated to the respective blocks.

Abstract: A optical disk recording and reproducing device capable of recording and reproducing data to or from an optical disk. Continuous signals representing continuous analog information such as audio and video information and discrete signals representing discrete data-information such as numerical data including program codes or character data are recorded dividedly in different recording regions provided on an optical disk including erasable or write once-type disks. The optical disk is rotated at a given linear or rotary angular speed under control by a disk rotation control device so as to simplify rotational control of the optical disk in accessing the information in the divided regions.

Abstract: Means for reducing the effects of vertical perturbations of a phonograph disc surface resulting from disc and/or playback system mechanical imperfections. Such imperfections are compensated by closed loop and/or open loop means wherein the deviations of the record path are detected and employed to minimize the effects of the mechanical imperfections.

Abstract: A circuit in a video disc playback device for detecting a state in which a disc motor rotation speed is double a normal rotation speed comprises a counter for counting a signal occurring at a timing intermediate between windows established for a timing at which a horizontal synchronizing signal is expected to occur and a double speed judgement circuit receiving a count by this counter and produces a double speed detection signal when the count has reached a predetermined value within a certain fixed period. The double speed detection signal is utilized for preventing an erroneous switching between AFC and PLL in the disc motor control such as an erroneous switching from AFC mode to PLL mode with phase locking in a double rotation speed.

Abstract: In order to reach precisely a predetermined place on an audio disk during a search run with contactless scanning, the scanning speed is determined from the speed of rotation of the disk. This occurs preferably at the beginning of the first recorded piece. The information concerning the speed of rotation of the disk is determined from the radial error signal. The arrangement is adapted for determining scanning speeds that vary among disks, and where each disk has a scanning speed that is unique to the disk and differs from the scanning speed of another disk.

Abstract: A video disc is provided with tracks which are arranged in a plurality of sectors. The tracks in the sectors are divided into groups each containing an integral number of video fields recorded on an integral number of tracks. The tracks within a given sector are adapted to be played back at a constant angular velocity, with the angular velocity varying inversely with the radius from sector to sector.

Abstract: A disc drive control system for controlling the drive of a disc carrying a binary digital signal including clock information of a predetermined frequency wherein the digital signal includes an information signal portion to be recorded and an synchronizing signal portion which includes successive maximum periods of inversion (transitions). The system includes a detection means for detecting the period of the transition of the synchronizing signal and producing a detection signal, (frame sync servo signal) disc a control means for producing a disc drive control signal for controlling a disc drive means. The drive control signal is produced in accordance with the detection signal prior to a period in which the drive control signal is produced in accordance with a reproduced clock signal (playback clock and playback frame sync signals), whereby eliminating the problem that the driving speed of the disc may be controlled in accordance with an erroneously reproduced clock signal.

Abstract: In order to eliminate a crosstalk component of the reproduction signal and to provide a high level of recording density, a method for recording an information signal having a synchronizing signal on a recording disc comprises a first step for forming a first portion of recording tracks in which information signal is recorded on the recording disc rotated at a constant angular velocity of rotation so that positions of the recording tracks in which the synchronizing signal is recorded are aligned in radial directions of the recording disc, and a second step for forming second portions of recording tracks in which the information signal is recorded on the recording disc under a condition that the angular velocity of the rotation thereof is varying, wherein the first and second portions of the recording tracks are formed alternately.

Abstract: A disc player for reproducing an information signal from a rotating disc having a spiral track on which a digital signal is recorded with a waveform obtained by the run length limited code modulation comprises a control circuit system wherein an interval representing the maximum or minimum run length in a reproduced signal from the disc is utilized for controlling the rotation of a motor for rotating the disc so as to keep the tangential velocity of the spiral track relative to a pickup device constant at predetermined speed and an additional control circuit system for detecting an interval of a constant level in the reproduced signal exceeding in length the interval representing the maximum run length obtained at the proper rotation of the disc, which appears when the reproduced signal from the disc is not properly obtained and therefore the motor is in danger of running away that is, being driven beyond a maximum speed by an ever-increasing energization voltage, and, when such an interval is detected, preve

Abstract: Method and apparatus for producing a mechanically reproducible recording in a metal disk record by operating an electrically excited cutting stylus to cut a modulated groove in the record, orienting the cutting stylus to be driven at a tracking angle of less than 5.degree., and electronically compensating recording distortions caused by this tracking angle.

Abstract: A video disc record of the constant angular velocity type (CAV) includes a spiral groove of constant pitch formed in a band on a surface thereof. The groove has a substantially constant nominal vertical dimension and vertical displacements which taper monotonically from an outer radius of the band to an inner radius. One component of the vertical displacement of the groove conveys an FM carrier wave of constant amplitude and relatively high frequency representative of picture information. A second component of the vertical displacement conveys one or more lower frequency FM carrier waves representative of sound information. The amplitude of the second component varies monotonically as a function of the groove radius within the record band to provide a disc having an improved audio FM carrier-to-noise ratio with no substantial perceptible increase in undesirable sound beat effects in images displayed when the disc is played.

Abstract: An optical-disk system is disclosed which comprises an optical-disk rotating in accordance with constant linear velocity technique, a signal input device for producing an information signal digitally encoded, and address generator for generating an address signal, an interleave circuit for commonly leaving both the information signal and the address signal, and a write controller for modulating a write beam incident to the optical-disk in response to the output signal from the interleave circuit and for forming at least one sector including both the commonly interleaved signals on the optical-disk.

Abstract: Piezoelectric video disc recording cutterheads have small and intricate geometries that make it difficult to compute or measure their mechanical characteristics, especially during the recording process. A monitoring circuit, for use during recording, for monitoring and measuring the mechanical characteristics of a recording cutterhead takes the form of a bridge network. The motional charge or motional current, which are related to the mechanical characteristics of the cutterhead, is measured by means of the bridge network. One branch of the bridge is arranged to include the piezoelectric cutterhead, the other branch comprises a variable capacitor which is adjusted to compensate for the shunt capacitance of the equivalent electrical circuit of the cutterhead. When the variable capacitance is properly adjusted the combination of the currents through the bridge network provides a signal representative of the displacement characteristics of the cutterhead.

Abstract: A monitoring circuit for monitoring and measuring the mechanical characteristics of a piezoelectric video disc recording cutterhead takes the form of a bridge network. The motional charge or motional current, which are related to the mechanical characteristics of the cutterhead, is measured by providing signals of a first polarity to one leg of the bridge and signals of a polarity opposite to the first to another leg of the bridge.One leg of the bridge includes the cutterhead and a sensing capacitor connected in series while the other leg includes the sensing capacitor and a balancing capacitor connected in series. When the capacitance value of the balancing capacitor is properly chosen, the voltage drop across the sensing capacitor is proportional to certain mechanical characteristics of the cutterhead (e.g., displacement).