Abstract: A method of rotation speed control for optical storage device is proposed. The method adjusts the rotation speed of an optical storage device to increase access probability and also enhance performance of the optical storage device. The method includes providing weighted values corresponding to a plurality of events that may happen during reading or writing processes of the optical storage device, providing an evaluation function, and determining a speed-up threshold and a speed-down threshold, which correspond to each rotation speed value, within a range of evaluation function values. Further included are when an event of the plurality of events happens, changing the evaluation function value according to the weighted value of the event, and when the evaluation function value is not within an domain between the thresholds, selectively changing the rotation speed of the optical storage device. The method further includes adaptively adjusting the thresholds and the weighted values.

Abstract: A disk drive unit for reproducing information recorded on a digital versatile disk (DVD). The disk drive unit has a copyright management information reading unit for reading copyright management information from a predetermined location on a DVD loaded into the disk drive unit, a first determining unit for determining whether or not protection exists for contents of the loaded DVD using the copyright management information read from the loaded DVD by the copyright management information reading unit, and a playback speed control unit for controlling a playback speed of the loaded DVD when it is determined that the contents of the loaded DVD are protected using the first determining unit.

Abstract: In a case of recording data into an optical disk (100), a disk apparatus (10) rotates the optical disk (100) by a ZCLV system, and in a case of reading out the data from the optical disk, the disk apparatus rotates the optical disk by a ZCAV system. By rotating the optical disk by the ZCLV system, a DSP (28) performs a read of a modified read carried out before recording, and a read of a verification carried out after the recording, and thereby, no occurrence of a change of a rotating speed of the optical disk among the modified read, the recording, and the verification.

Abstract: A disk apparatus (10) includes an optical pick-up (12) and a DSP (28), and irradiates a laser beam onto a recording surface of a disk recording medium (100) by the optical pick-up. In a case that a time period (access time period) required for a seek is shorter than a time period (changing time period) required for the number of rotations, the DSP does not simultaneously perform a change of the number of rotations and the seek. To the contrary, the DSP delays the seek by |access time period?changing time period|, and performs a recording and a reproduction after the change of the number of rotation is ended.

Abstract: An optical disc controller for an optical disc drive playing optically a first information storage medium and a second information storage medium having a higher storage density than the first medium. The controller includes: a rotation control section for controlling a rotating mechanism rotating the media; an equalizer for removing first frequency range components from an RF playback signal, obtained by irradiating each media with light and detecting reflected light, and amplifying second frequency range components; and a phase locking section for generating a sync clock signal to do synchronization detection with a digital playback signal obtained by digitizing the output of the equalizer. The rotation control section rotates the media while controlling the rotating mechanism such that RF playback signals are obtained at first and second transfer rates.

Abstract: Information indicative of disk-applicable recording speeds is incorporated in lead-out start time information within ATIP information that is recorded in pre-grooves located in a lead-in area of an optical disk. Once the optical disk is inserted in an optical disk recording device, the lead-out start time information is read out, so that recording is performed on the optical disk after a recording speed is automatically set to a highest settable speed value within a range specified by the read-out lead-out start time information. This arrangement can reliably prevent recording at speeds beyond predetermined limit values unique to the optical disk.

Abstract: A system and method for controlling operation of a motor system that addresses the design challenges for the small form factor optical disk system. The control system can be operable to read a physical sector address (PSA) from an optical medium, calculate a table index based on the PSA, enter a lookup table module to acquire reference data, and maintain a constant data rate transfer from the optical medium for a range of PSAs.

Abstract: A disc drive device optimally controls a speed for reading RTR-format data, such as video and audio, recorded on a DVD-format disc, thereby enabling real-time playback without interruption. In the disc drive device, information added to each sector is used for determining whether data is RTR-format data. When an error occurs at high-speed reading of RTR-format data and therefore the reading speed is changed to a low speed, the reading speed is so controlled as to be kept at the low speed for reading the following RTR-format data. Thus, for RTR-format data, overhead due to repetitive acceleration and deceleration processes can be avoided, and reading can be carried out without interfering with real-time playback. For normal data, reading can be carried out in a manner similar to that in the background art.

Abstract: An optical disc device records data on an optical disc by projecting a laser beam on the optical disc such that a linear density of the data becomes substantially constant. The optical disc device comprises velocity judging means, velocity changing means, recording velocity detecting means, and recording velocity transmitting means. The velocity judging means is for judging a recordable velocity for an optical recording medium inserted into the optical disc device. The velocity changing means is for changing a recording velocity designated from a host. The recording velocity detecting means is for detecting the recording velocity during a recording. The recording velocity transmitting means is for transmitting information concerning the detected recording velocity to the host.

Abstract: The power consumed by a data storage device having at least one disk connected with a spindle can be reduced by reducing the rotation rate of the spindle to a rotation rate greater than zero. In one method in accordance with the present invention, wherein a head is in communication with each disk, the spindle can be rotated at a first rotation rate. The head can be parked and the rotation of the spindle can then be reduced to a rotation rate greater than zero. By reducing the rotation rate of the spindle, the power consumed by the spindle can be reduced by approximately the ratio of spin speeds to the exponential power of 1.5. This description is not intended to be a complete description of, or limit the scope of, the invention. Other features, aspects, and objects of the invention can be obtained from a review of the specification, the figures, and the claims.

Abstract: One aspect of the present invention provides a motor control system that includes a linear control system operative, in a linear mode, to provide a plurality of control signals for driving an associated motor based on an error signal. The system also includes control logic operative, in a pulse-width modulation (PWM) mode, to provide the plurality of control signals for driving the motor, at least some of the plurality of control signals being pulse-width-modulated signals based on the error signal. An error system generates the error signal based on an indication of a sensed electrical characteristic of the motor relative to a predetermined reference signal. A feedback network is coupled across the error system. The feedback configured to have transfer function characteristics that substantially match responses in the linear mode and the PWM mode of motor control system, which facilitates transitions between the linear mode and the PWM mode.

Abstract: A disk drive includes an information processor 15 for reading out or writing information from or to the disk drive, a disk drive unit 11 for driving a disk 10, an access unit 12 for reading out or writing information from or to the disk 10, and a controller 13 for controlling the disk drive unit 11, and a disk controller 14. The disk drive is driven at a set drive speed. Format identification information is acquired from information recorded on the disk 10, and drive-speed information for the disk drive, determined from the acquired format identification information, is transmitted to control the speed of the disk.

Abstract: The present invention provides an optical disk reproducing apparatus capable of providing special reproducing (replay) mode using a jog dial in a manner similar to the special reproduction using an analog record player such as scratching etc. When the operation disk is rotating at a same predetermined speed as the rotation speed of the disk, the normal reproducing (replay) is performed. The special reproducing (replay) such as scratching is performed when the operation disk is turned, and the turning speed and direction of the operation disk are detected.

Abstract: A reproduction apparatus and a reproduction apparatus are disclosed which can reduce the settling time until high speed continuous reproduction is resumed after such high speed continuous reproduction is interrupted. If continuous reproducing a disk-type recording medium is interrupted during high speed reproduction, then the rotational speed of the disk-type recording medium is lowered once from the speed for high speed reproduction to a normal reproduction speed. Then, when a continuous reproduction operation is performed again, the rotational speed is changed over from the normal reproduction speed to the high rotational speed for high speed reproduction.

Abstract: The present invention discloses a method of adjusting a rotation speed of an optical disc drive for a spindle motor controlled by a host to rotate and read an optical disc. First, it is determined whether the data read by the optical disc drive is in Mode 1 or Form 1 of Mode 2. If in Mode 1 or Form 1 of Mode 2, it is determined whether the frequency of read request commands output from the host is lower than a predetermined value or not. If the frequency of read request commands output from the host is lower than the predetermined value, then it is determined whether the response data output to the host is sequential reading data or not. If the three situations mentioned above are all sustained, the data read by the optical disc drive is ascertained as MP3 data. Thus, the rotation speed of the spindle motor is decreased to a lower value.

Abstract: An information recording apparatus includes a data writing part that writes data transferred from a host computer onto a data-recordable recording medium, a data writing pause part that pauses writing of the data by the data writing part, a data writing rate change part that changes a writing rate at which the data writing part writes the data, a data writing restart part that restarts the writing of the data, and a data writing control part that controls the data writing pause part, the data writing rate change part, and the data writing restart part.

Abstract: An optical disk recording method comprising steps of a) performing recording onto the optical disk with a ZCLV method by using zone parameter storage means for storing at least one zone division time and CLV of each zone in a track formed on the optical disk, as zone parameters, for each of a plurality of recording modes and optical disk type determination means for determining the type of the optical disk before recording; b) performing optimization of the recording velocity by detecting, before recording, servo signal fluctuation by accessing the optical disk, by determining maximum recording velocity defined by the speed of a rotational motor rotating the optical disk, and by calculating a changing point of the recording velocity; and c) limiting the speed of the rotational motor, when the servo signal fluctuation at the surface of the optical disk exceeds a reference level and determining the relation between the zone division time and the CLV of each zone.

Abstract: The present invention relates to method and apparatus for recording new data in a writable disk such as a once-writable disk CD-R and a rewritable disk CD-RW after previous recording to the disk is interrupted abnormally. A method of determining a recordable position of a writable disk according to the present invention, reads data recording information of the writable disk, examines whether or not an area after a recordable position indicated by the read data recording information has recorded data, and changes the recordable position to another position for new input data if the area has recorded data. Therefore, new data is always written after any uncompleted data track without being written over previously recorded data even if the recording information of an uncompleted data track is wrong or unusable.

Abstract: A disc speed control device for use in a disc player and/or recorder having a pick-up for reading/recording data. The device comprises an inner loop which regulates a determined disc rotation speed value received at its input and an outer loop which delivers this speed value depending on a frequency at which data is read by the pick-up. The present invention is particularly useful in multistandard disc drives which need to adjust to different disc speed modes, for example, constant angular velocity, or constant linear velocity.

Abstract: A CLV optical disc capable of recording the information with a constant linear velocity. In the CLV optical disc, plural lines of specified track exist in the predetermined data area, railroad length of the tracks is integer times of the length of a sector, the length of the sector on the specified tracks is 2×?×N times of a track pitch, the number N is a positive integral number, and head positions of the specified tracks are lined up on a predetermined radius line A—A? at equal track intervals. Fixed-length track marks are arranged at equal physical length intervals along the information track formed in the state of a spiral. The track position information is obtained by detecting the track marks of the present and adjacent tracks. The CLV optical disc medium recording/reproducing apparatus can perform the seeking operation by use of the CPU and the other relevant units regardless of the operation of controlling the disc revolution number.

Abstract: OPC data record in an optical disk is performed at a plurality of record velocities to obtain a maximum record velocity Vlmax. A rotation number of the optical disk is calculated and set, the rotation number being determined in such a manner that the maximum record velocity Vlmax becomes equal to a linear velocity of the optical disk at a detected record position of the optical disk along the radial direction. The optical disk is rotated under a rotation control that a detected actual revolution number of the optical disk becomes equal to the calculated and set rotation number. It is monitored to check whether the record operation of the optical disk at the maximum record velocity Vlmax is normal. If it is detected that the record operation may become abnormal, the maximum record velocity is lowered by ?v1.

Abstract: The present invention relates to method and apparatus of recording data onto a disk recording medium in zoned-CLV mode while adjusting recording speed and recording condition adequately at every speed change point between zones. The present invention detects a current recording position while recording data along a track of the disk recording medium, adjusts a recording speed and resets both a write strategy and a base B-level used for running OPC to be suitable for the adjusted recording speed. The present invention can record input data onto a writable disk with the most suitable writing condition at the highest allowable speed.

Abstract: A system and method for controlling operation of a motor system that addresses the design challenges for the small form factor optical disk system. The control system can include a first module for providing a period error, a proportional gain (Kp) and an integration gain (Ki); a second module for operating on the Ki and Kp to provide an output; and a third module for commutating the motor in response to the output.

Abstract: A reproducer can enhance detection accuracy with respect to a rotational motion according to a scratch operation and properly change a reproducing speed of a recording medium. A turntable of a scratch operating part comprises a disk-shaped mounting plate, which is made from metal, fixed on the upper end of a bushing, a ring-shaped grooved member fixed on a marginal area of the under surface of the mounting plate with mounting bolts, and a marginal member fixed on an outer area of the ring-shaped grooved member. A disk has a disk surface on rollers provided on the top surface of the turntable and a ring-shaped detected part located around an outer circumference of the disk surface and projecting from the under surface of the disk. A light receiving element supplies a signal with a frequency proportional to a period in which a concave part and a convex part pass according to the rotational speed of the disk.

Abstract: A multimode filter in an optical storage device is used for filtering an error signal and outputting a frequency signal. The multimode filter comprises a CLV and CAV mode filter and a switch. The CLV mode filter is used for filtering the error signal and extracting a narrow bandwidth signal, whereas the CAV mode filter is used for filtering the error signal and extracting a wide bandwidth signal. The switch is used for selecting either the CLV mode filter or the CAV mode filter according to the recording mode of the optical storage device.

Abstract: In an optical disk drive, an OPC is performed prior to a start of recording of an optical disk by accessing a power calibration area of the disk with a light beam emitted by a light source while the disk is rotated at a constant linear velocity. An optimum recording power for the light source during the recording is determined based on results of the OPC. A highest linear velocity of linear velocities is changed to a next highest linear velocity for a controlled velocity of a disk rotation device during a subsequent OPC. It is detected whether the OPC and the determination are normally performed after one of the linear velocities is set. The controlled velocity during the recording is set to an angular velocity corresponding to the one of the linear velocities at which the OPC and the determination are normally performed.

Abstract: A system, method, and apparatus for recovering from performance errors in an optical disc drive is provided for optical media with a pitted premastered area that cannot be overwritten and a grooved user-writeable area that can be overwritten. The system includes instructions operable to detect a problem with at least one of: focus control, tracking control, or spin control when accessing the optical media; instructions operable to save the current state of the disc drive; instructions operable to attempt to recover from the problem; and instructions operable to restore the current state of the disc drive after recovering from the problem.

Abstract: An optical drive that detects a communication link interface speed to a host device and changes an optical media writing speed to reduce the likelihood that an error will occur during writing caused by an insufficient data interface rate in relation to the writing speed. In certain embodiments, the process for detecting and storing the preferred recording speed may be a software module which is part of the firmware of the optical drive. The invention provides a method of determining the preferred recording speed based on the interface speed and the maximum recording speed of the optical drive and storing this preferred recording speed for retrieval during recording of optical media.

Abstract: A method used in a CD-R/W drive for coordinating the writing and reading speeds of a CD-R/W drive is disclosed. With the aid of the method, the writing speed of the CD-R/W drive is able to be adjusted, and thus a more stable writing operation is obtained. In the method, if the time(s) that the buffer has been cleaned up is/are not larger than the predetermined value, the CD-R/W drive will write data to the CD-ROM at its highest speed. On the contrary, if the time(s) that the buffer has been cleaned up is/are larger than the predetermined value, the CD-R/W drive will slow down stepwise from the current speed to a lower speed. To accomplish the invention, the CD-R/W drive is either controlled by computer programs or by a programmably pre-written control chip that is installed in a control circuit inside the CD-R/W drive itself.

Abstract: There is provided an apparatus for compensating for an eccentricity of an optical disc, including a driver on which an optical disc is mounted for rotation, an optical head for emitting optical beams to the optical disc and receiving optical beams reflected from the optical disc, a mover to which the optical head is secured and which moves in a radius-wise direction of the optical disc, a track cross generating circuit which receives a track error signal from the optical disc and transmits a track cross pulse, and a controller which receives the track cross pulse to thereby determine an eccentricity of the optical disc in view of the optical beams reflected from the optical disc, and controls a rotational frequency of the optical disc in accordance with the thus determined eccentricity. The apparatus provides an advantage that an average transfer rate is increased for the long run.

Abstract: In an optical disc drive, the read channel electronics and the wobble channel electronics are combined into one common channel, for reduced cost. When the drive is reading, the common channel is used for primary data and a read clock. When the drive is writing, the common channel is used for wobble data and a write clock. Two example embodiments are provided. In each example, a single front end amplifier, without automatic gain control, is used. In each example, a single PLL and a single data detector are used.

Abstract: A method for controlling the rotational speed of a disk player includes first calculating the proportion of time which the disk player is reading data from the disk during a unit time T. Thereafter, the method increases the rotational speed of the disk player if the proportion of time that the disk player spends reading data from the disk is greater than a first threshold during each of m consecutive units of time T, and decreases the rotational speed of the disk player if the proportion of time that the disk player spends reading data from the disk is less than a second threshold during each of n consecutive units of time T.

Abstract: The present invention relates to an apparatus and method for adjusting the reproduction speed of an optical disk, and more particularly, to a method for adjusting the reproduction speed of an optical disk which is capable of selectively adjusting the reproduction speed to a lower speed in advance only with respect to an abnormal regional section of the optical disk inserted into a driver, and normally reproducing a recording signal on the optical disk at the original high speed with respect to sections excepting for the abnormal regional section. Thus, there is an effect of reproducing data at a high speed even if the state of the optical disk is bad. In addition, a delayed reproduction time delayed can be removed by gradually reducing the reproduction speed of the optical disk.

Abstract: A position detecting apparatus detect the moving position of a mobile element. The apparatus includes the mobile element moving reversibly along a specified running path, a conductive electrode disposed along the running path, a detecting electrode disposed on the mobile element, and a detector for detecting contact or non-contact between the conductive electrode and detecting electrode. The detecting electrode is disposed so as to contact or not to contact with the conductive electrode by the move of the mobile element. The position of the mobile element is detected by the detector.

Abstract: A power saving system of an optical recording/reproducing apparatus is provided. The optical recording/reproducing apparatus includes a temporal memory which stores reproduced data or recording data in a cyclic data storage stage and from which the stored data is read out for reproduction or recording in a cyclic data readout stage following the data storage stage. The power saving system saves part of power consumed in the apparatus in the data storage stage in a record mode of operation and in the data readout stage in a reproduce mode of operation.

Abstract: Provided is a disc drive device that optimally controls a speed for reading RTR-format data, such as video and audio, recorded on a DVD-format disc, thereby enabling real-time playback without interruption. In the disc drive device, information added to each sector is used for determining whether data is RTR-format data. When an error occurs at high-speed reading of RTR-format data and therefore the reading speed is changed to a low speed, the reading speed is so controlled as to be kept at the low speed for reading the following RTR-format data. Thus, for RTR-format data, overhead due to repetitive acceleration and deceleration processes can be avoided, and reading can be carried out without interfering with real-time playback. For normal data, reading can be carried out in a manner similar to that in background art.

Abstract: A disk recording medium including a pregroove on which control information is recorded, the control information having disk-compatibility information, and the disk-compatibility information indicating a linear recording velocity corresponding to the disk recording medium.

Abstract: Physical addresses of the recording areas provided on an optical disc are represented in a time-axis data format and in a binary data format. The physical address value gradually increases from the inner part of the disc to the outer part of the disc, while the formats remain in one-to-one correspondence over the recording areas. The distance the optical head must move to reach a target recording area can therefore be calculated easily independently of where on the disc the optical head is located, enabling the optical head to quickly access the target recording area.

Abstract: The invention features a fly height measurement system for measuring fly height of a slider over a storage disc. The fly height measuring system includes a source of light, a slider, a detector module and a processor. The source of light produces light along a light path. The slider includes an objective lens positioned such that light from said source hits the objective lens and is directed toward a surface of a disc. Light propagating from the disc is directed to a detector. The processor estimates the fly height of the slider based on detector module output.

Abstract: A device according to the invention for scanning a rotating information carrier (2) comprises a transducer (10) and controller (20, 22) for controlling a scanning parameter of the transducer (10), such as the radial position and the setting of a focus. The controller comprise difference signal generator (20) for generating a difference signal (RE) which is indicative of a difference between a current value and a desired value of the scanning parameter, and correction signal generator (22) for generating a correction signal (SC) in response to the difference signal. The correction signal generator (22) comprise a delay loop (25) having first in first out memory (36) for generating a delayed signal (SDL1) and feedback filter (38) for filtering the delayed signal (SDL1).

Abstract: When a deviated gravity disc is reproduced at a higher rate with the disc reproducing apparatus, an excessive vibration is generated and this vibration gives adverse effect on the disc reproducing apparatus and peripheral components/apparatuses, and/or may represent an annoyance to a user. A vibration information detector for detecting vibration of the disc reproducing apparatus or a deviated gravity information detector for detecting amount of gravity deviation of disc is provided, and as a result of such detection of an imbalance (i.e., excessive vibration or mass eccentricity), and a reproducing rate switching control controls sets and limits the reproducing rate of the disc reproducing apparatus to a substitute speed which is lower or higher than a normal reproducing speed.

Abstract: A method for controlling the speed of a spindle motor of an optical information reproducing apparatus is provided. The method determines whether a data quantity of a buffer memory is sequentially larger than a first predetermined quantity during a period of read operation. If yes, the spindle motor is decelerated to a predetermined speed. The method also determines whether the data quantity of the buffer memory is sequentially less than a second predetermined quantity during a period of read operation. If so, the spindle motor is accelerated to a predetermined speed. The method according to the invention can automatically tune the speed of the spindle motor to a suitable speed to eliminate the noise that normally accompanies faster operation without lowering the information reproducing efficiency of the optical information reproducing apparatus.

Abstract: Servo control circuitry 300 includes a digital to analog converter 402 for converting digital servo control data into a pulse width modulated signal. A first conductor transmits the pulse width modulated signal to an external device 409. A second conductor transmits a reference signal derived from the clock signal to external device 409, external device 409 differentially receiving the pulse width modulated signal with respect to the reference signal.

Abstract: A control apparatus and method for controlling a velocity of a spindle motor included in an optical disk reproducing system to prevent a forward or backward overrun of a spindle motor are disclosed. A widest signal detector of the apparatus detects the widest pulse width of an eight-to-fourteen modulation (EFM) signal according to a main clock signal and generates a first status signal representing a status of the pulse width of the detected signal according to a frame clock signal, which is divided by a first predetermined number j. A narrowest signal detector of the apparatus generates a second status signal representing a status of the narrowest pulse width of the first status signals according to the frame clock signal divided by a second predetermined number k, where k is greater than j. An overrun controller increases or decreases or holds a previously counted result according to the frame clock signal divided by the second predetermined number and the second status signal.

Abstract: To provide a disk playback system that effectively uses the maximum playback speed and maximum search speed that the system owns. A disk playback system that searches for a desired position of a disk (2) on which information data is recorded at constant linear velocity after receiving a command from an external device, reads out desired information data, and outputs information data corresponding to the playback format of the disk. An outermost-perimeter-address memory circuit (21) renews stored address information to the newest address information, if the address information of the newest address accessed according to an access instruction of said disk indicates the newest address is outer perimeter than the outermost address that has been accessed, and determines a criterion for speed control of the disk (2), based on the renewed address information. A CAV control circuit (20) controls the speed of the disk 2, based on the determined criterion.

Abstract: A clock signal generating system of the present invention is provided for recording information on a disc. The disc has a plurality of recording tracks wobbled by a wobble signal having a predetermined frequency and a plurality of prepits disposed at positions having a predetermined phase relation with respect to a phase of the wobble signal. A clock signal is generated based on the wobble signal. A prepit signal is produced from the prepit. The phase of the wobble signal is compared with a phase of the prepit signal, thereby generating a phase adjusting signal. The phase of the clock signal is adjusted based on the phase adjusting signal. A recording clock signal for recording the information is produced by an adjusted clock signal.

Abstract: A servo control apparatus for carrying out a servo control when information is reproduced from an information record medium having an embossed area where information cannot be recorded, such as DVD-RW, is provided. The servo control apparatus detects a position of a light spot formed by the light beam except the embossed area on the information record medium, and shifts the light spot beyond the embossed area to a predetermined target position to be radiated with the light beam, which is positioned in another side of the embossed area on the information record medium, on the basis of the detected position.

Abstract: Read data is given reproduction processing, including data correction, in synchronism with a bit clock. A disk with signals recorded thereon according to a constant linear velocity method is able to be rotated under control according to a constant angular velocity method. The rotation controller is set free from the control by the operation suspend controller. With this arrangement, the disk continues to rotate even when data writing to the buffer memory is suspended, and, upon resumption of a signal reading from the desk, signal processing is promptly carried out to a signal read from the disk, irrespective of the radial dimension of the point from which the signal was read on the disk.

Abstract: The frequency rectification filter, in principle, measures an amplitude and phase of a particular frequency and compresses the frequency. Accordingly, if no initial value is present, it is necessary to take a time more than one turning cycle. Consequently, no effect can be seen immediately after the rise of an apparatus, and head positioning takes much time. The object of the present invention is to reduce this time. According to the present invention, a state amount of the frequency rectification filter is stored in memory before unloading the head from the disc, so that at apparatus rise, the spindle rotation angle is matched so as to operate the filter, thus increasing the speed of the rise of the effect of the frequency rectification filter. Thus, the risa of the frequency entire apparatus can be performed rapidly.

Abstract: For scanning a disc-shaped information carrier at a high average information rate with minimum access time, the angular velocity is decreased substantially as the radial distance to the scan location increases, while at the same time the linear velocity of track scanning increases substantially. The track may be divided into zones which are scanned with constant angular velocity. With respect to the inner tracks of at least two adjacent zones, or the innermost and the outermost tracks, the angular velocity decreases less than inversely with increase of radial distance, while the linear velocity increases less than proportionally with increase of radial distance.