Abstract: Optimum power control also known as OPC is performed while changing a recording speed and a recording laser power level. Signal recorded through the optimum power control is reproduced for measurement of reproduced signal quality. Recording speed achieving a recording laser power level that can provide reproduced signal quality falling within a predetermined acceptable range is displayed as a recommendable recording speed so that a user can set the displayed speed as a recording speed for use in actual recording.

Abstract: A disk reproducing device comprising: clock signal extracting means for extracting a regenerative clock signal from a reproduced signal; synchronization detecting means for detecting a synchronizing signal from the reproduced signal; extracted clock signal verification means for verifying that the regenerative clock signal is correctly extracted; signal processing means for performing variable linear velocity reproduction; target reproducing speed setting means for setting a target reproducing speed; reproducing speed verification means for verifying that a reproducing speed reaches the target reproducing speed; and signal processing start command generating means for outputting a signal processing start command referring outputs of said extracted clock signal verification means and said reproducing speed verification means.

Abstract: A method for controlling reproduction speed of an optical disk is disclosed in which when a data recorded in an optical disk is read, stored and transmitted to a connected instrument through a digital interface, the speed in reading and reproducing the data recorded in the optical disk is controlled to be varied at a high speed or at a low speed according to a transmission rate or a residual amount of the stored data. By doing that, the output image is prevented from temporary pausing and noise images such as a flicker is originally prevented from outputting.

Abstract: A motor control apparatus according to the present invention comprises: a servo circuit for outputting a pulse width modulation signal; a low-pass filter for receiving the pulse width modulation signal outputted by the servo circuit as an input; and a driver circuit for receiving an output voltage of the low-pass filter as an input and thereby driving a brushless sensorless motor; wherein the servo circuit controls pulse width of the pulse width modulation signal so as to maintain rotational speed of the motor at a target rotational speed on the basis of an FG pulse signal outputted by the motor, the FG pulse signal representing the rotational speed of the motor by frequency. The motor control apparatus further includes a rotational speed changing means, the rotational speed changing means changing the rotational speed of the motor by gradually varying a voltage outputted by the driver circuit from a current voltage to a target voltage on input of a control start signal.

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: 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: An optical disc apparatus being able to read and write from and into an optical disc of a wobble groove type or method, a rotation control of a spindle motor is performed including a spindle controller portion and a PWM oscillator generating a clock for use of rotation control, wherein the frequency of the clock for use of rotation control is set to be different from that of a wobble signal or outside an area ±50% of wide capture fluctuation of the wobble signal, thereby providing the optical disc apparatus with which external disturbance on the wobble signal or the like can be reduced and a stabilization of the optical disc apparatus can be obtained.

Abstract: An optical recording/reproducing apparatus capable of using disc cartridges of at least two different sizes and/or a naked disc, on only one tray. The optical recording/reproducing apparatus is also capable of recording and/or reproducing information on/from one of the discs mounted on the tray by automatically detecting the disc cartridges and/or the naked disc positioned on the tray.

Abstract: In a method of the present invention for controlling stepping motor, the stepping motor driving current is increased or reduced at a fixed inclination in proportion to the time to control the stepping motor effectively, and, a stepping motor driving current pattern is changed by 1/4 cycle or over to synchronize the state of excitation between the stepping motor driving means and the stepping motor to control the pick-up very accurately. In addition, the disk apparatus of the present invention, which uses a stepping motor is provided with a pulse rate pattern variable means, a pulse rate change proportion measuring means, and a driving voltage variable means, and when the pulse rate and the pulse rate change proportion are low, the driving voltage amplitude is lowered to reduce surplus torque generation in the stepping motor.

Abstract: The optical disc reproducing apparatus comprises an ATIP demodulator which is supplied, from a matrix amplifier, with a wobble signal incorporating an address information in a modulated component thereof. In the ATIP demodulator, the free-run frequencies of the pair of VCOs change correspondingly to a moved position of a sled. Therefore, the ATIP demodulator can work well even if the carrier frequency of the wobble signal changes.

Abstract: CD-ROMS of poor quality, such as those having eccentric center holes or uneven weight distributions circumferentially, are easy to wobble or otherwise vibrate when driven at high speed, overloading tracking and focusing servos and inviting read errors and retries. Each CD-ROM on being loaded into a CD-ROM drive is therefore checked as to its quality in terms of the speed of rotation at which the disk drive motor gains a steady state on being started up at a full supply voltage. The poorer the disk quality, the lower is the steady state speed of motor rotation. A poor quality disk is read at four times the standard audio CD speed, an intermediate quality disk at eight times that speed, and a good quality disk at twelve times that speed.