摘要:
An optical disk unit for recording information on and reproducing information from a disk recording medium by projecting a light beam thereonto includes a signal level detection part detecting a level of a track error signal generated based on reflected light of the light beam from the disk recording medium, a scattered light detection part detecting scattering of the reflected light, and an off-track detection part which detects an off-track of the light beam using detection signals supplied from the signal level detection part and scattered light detection part.
摘要:
An optical disk reproducing apparatus uses a spindle motor having a low torque to reduced power consumption and manufacturing cost while maintaining a low error rate for reproduced data. The spindle motor is rotated at a constant rotational speed under a CAV control when a pick-up is moved. The rotational speed of the spindle motor is switched to a reference linear speed under a CLV control when a reproducing operation is performed. The reference linear speed is established for each of the zones of a recording area of an optical disk. The reference linear speed is determined by generating a zone clock set for each of the zones. A frequency error signal is generated by comparing the zone clock with the reproduction data so as to maintain the spindle motor at the reference linear speed determined by the zone clock.
摘要:
This digital data reproducing apparatus is adapted to prevent reproduction errors of data, wherein a read gate opened when a fixed pattern in a header field for phase locking is detected is kept opened until the data reproduction in a data field is completed, whereby the phase locking in the data field is performed still in the same low-speed mode as when the PLL pull-in is completed in the header field, with the responding ability lowered to defects such as voids or the like in the phase locking pattern area in the data field.This digital data reproducing apparatus is adapted to prevent reproduction errors, wherein, when a reproduced data in a data field is locked, a read gate is opened after a fixed pattern recorded for phase locking is surely detected, so that the phase locking is started in a high-speed mode, while avoiding erroneous operations of the PLL.
摘要:
A method and apparatus well suited for the conversion of a digitized audio signal into analog form with as wide a dynamic range as possible. A digital dither signal is added to a digital audio or like data signal to provide a digital data/dither signal. This digital data/dither signal and the digital dither signal are both converted into an analog data/dither signal and an analog dither signal respectively, and the analog dither signal is subtracted from the analog data/dither signal to obtain an analog data signal equivalent to the digital data signal. The level of the incoming digital data signal may be so high that when the digital dither signal is added thereto, the total level of the data/dither signal may exceed the capacity of the digital to analog converter in use. In that case the digital dither signal is either gated off or reduced in level, with the result that the digital to analog converter inputs either the data signal only or the data/dither signal having a total level not exceeding its capacity.
摘要:
A disk inspection apparatus for discriminating disks. The disk inspection apparatus has an ECC control section and a comparison section. The ECC control section measures the number of error corrections PIE and the number of error correction failures PIF in a predetermined section of the disk. The comparison section discriminates the disk as a disk with a deterioration in jitter characteristic when the minimum or the average of the PIE exceeds a first threshold value; discriminates the disk as a normal disk when the maximum of the PIF is equal to or smaller than a second threshold and the minimum or the average of the PIE is equal to or smaller than the first threshold value; and discriminates the disk as a scratched disk when the minimum or the average of the PIE is equal to or smaller than the first threshold value and the maximum of the PIF exceeds the second threshold value.
摘要:
A disk drive and an information processing system optimizes the number of rotations of a disk. Data read from a disk and previously-read cache data are temporarily stored in buffer memory. When a total amount of cache data achieved during a given period of time T1 or an average amount of the same is equal to or less than a threshold value X1, a system controller controls the number of rotations in an increasing manner, thereby optimizing the number of rotations. When a total amount of cache data achieved during a given period of time T2 (T1
摘要:
An optical disk apparatus for recording test data onto an optical disk while changing the level of recording power and determines the optimum recording power with reference to the quality of a reproduced signal of the test data. A modulation degree or a γ value is calculated from a reproduced signal of the test data, and the gradient of a change of the modulation degree or the γ value relative to the recording power Pw is calculated. Further, a target recording power is determined utilizing an area where the gradient of the change is relatively sharp, and the optimum recording power is determined based on the target recording power.
摘要:
An optical disk recording apparatus for recording information onto a write-once or erasable optical disk has a memory component including a table of prerecorded correction curves consisting of recording power correction values corresponding to radial positions for each type of a variety of different optical disks, a correction component for correcting the recording power in an optimum power control operation (OPC) operation using the appropriate correction value, and a recording component for recording information onto the optical disk using the corrected recording power.
摘要:
A method of production of cement bonded agglomerated ore not depending on yard curing which can improve the environment, save labor, and improve yield is provided, that is, a method of production of cement bonded agglomerated ore which adds Portland cement as a binder to dust produced from an iron works and/or fine powder ore, treats the same by mixing, moisture adjustment, and kneading steps, then pelletizes it by a pan pelletizer and suitably thereafter cures it to produce blast furnace-use cold pellets or sintering-use minipellets having the required crushing strength, which method charges the raw pellets from the top of a vertical type container and discharges them from the bottom end to form a moving bed and cures the raw pellets in the period from charging to discharging.
摘要:
A data recording apparatus and a data reproducing apparatus which ensure security of a portable recording medium, such as an optical disk. The apparatus has a security mode and a normal mode as operation modes. In the security mode, a system controller of the apparatus records a security identification signal in an area other than a user data area of the optical disk. At the time of copying of the optical disk, the security identification signal disappears, and a limitation is imposed on reproduction, thereby preventing copying operation. In the security mode, the system controller records the security identification signal in the area other than the user data area of the optical disk, as well as recording user data by means of converting an address through use of a password. At the time of reproduction of data, absence or presence of the security identification signal is ascertained. When the security identification signal is present, the address is inversely converted, thereby reproducing data.