摘要:
An equalizer (22) performs a PR equalization of a reproduced signal waveform output from an A/D converter (21). A reference-waveform generation unit (42) generates a reference reproduced-waveform based on a recording data train estimated from the reproduced signal waveform by a recognition unit (30). An equalization-error calculation unit (43) calculates an equalization error between the reference reproduced-waveform and the reproduced signal waveform. A transient equalization-error detector (44) extracts equalization error information, as a transient equalization error, at the time instant at which the reference reproduced-waveform assumes a specific level, and at which the specific level-value and a level-value of the reference reproduced-waveform at one channel clock before or after the time instant satisfy therebetween a specific relative relationship. The extracted transient equalization error is used as an index showing the quality of the recorded mark.
摘要:
Reproduced signals are equalized by the least square technique by using a predetermined number of data samples binarized by a Viterbi decoder. Even when data written on an optical disk is unknown, the data can be equalized in a stable manner and can be reproduced at a low error rate without instability factors such as divergence due to interference.
摘要:
[PROBLEMS] To reduce the number of recording condition adjustment steps before information recording, simplify the recording condition adjustment procedure, and perform stable and accurate recoding condition adjustment of an information recording medium.[MEANS FOR SOLVING PROBLEMS] When recording information on a recording medium, the recording condition is optimized. Next, under the optimized recording condition, a signal is recorded in a prescribed area of the information recording medium. Next, by using the signal recorded under the optimized recording condition, a part of the recording condition for the next and later is adjusted. Thus, a part of the recording condition is adjusted by using the signal recorded under the optimized recording condition and accordingly, it is possible to rapidly perform the recording condition adjustment before information recording.
摘要:
In an optical disk system using a PRML identification system, a method for deriving an optimum recording wave in a short period of time is provided. Parameters of the recording wave are adjusted by using an evaluation value obtained by a signal evaluation method which is suitable for the PRML identification system as an index. In this case, as a parameter adjusting method, a plurality of adjusting methods are utilized.
摘要:
In an optical disk system using a PRML identification system, a method for deriving an optimum recording wave in a short period of time is provided. Parameters of the recording wave are adjusted by using an evaluation value obtained by a signal evaluation method which is suitable for the PRML identification system as an index. In this case, as a parameter adjusting method, a plurality of adjusting methods are utilized.
摘要:
For the purpose of reducing the time for information processing in an array type disk device provided with a plurality of optical disk devices, when a beginning address is notified from any one of the optical disk devices to a main control device of the array type disk device, the main control device determines the beginning address notified first as a writing start address, without waiting for a notification of a beginning address from any other optical disk devices. Then, the main control device notifies the determined writing start address to the respective optical disk devices. Accordingly, even if search times for the writing start address are different among the optical disk devices, all the optical disk devices can start the writing of information based on which optical disk device has most quickly notified the beginning address.
摘要:
An optical disk device includes an optical head unit, a drive means and a recording surface state determination means, and determines the type of an optical disk based on a state of the information recording surface. The information recording surface includes a management region on which management information is recorded and formed by a guiding groove or a prepit sequence and a data recording region on which a user data is recorded and on which a track formed by a guiding groove or a prepit sequence. The optical head unit irradiates a focused beam onto the information recording surface of an optical disk which rotates. The drive means drives to move the focused beam along a radial direction of the optical disk by driving the optical head unit. The recording surface state determination means determines a state of the information recording surface based on a reflected light of the focused beam. The optical disk device determines the type of the optical disk based on a state of the information recording surface in a determination region being set to straddle between a management region and the data recording region.
摘要:
Reproduction signals include patterns for which recognition errors are likely. With respect to such patterns, probable error patterns are prepared. Tables showing correct patterns and error patterns are prepared, and evaluation values accurately representing signal quality are calculated. In an apparatus using a PRML method, discrimination data and a plurality of predetermined bit sequence pairs are examined to detect matching. A bit sequence and corresponding two ideal responses are calculated. Euclidean distances between the two ideal responses and equalization signals are obtained, and the difference between the Euclidean distances is further obtained. A quality evaluation value of a reproduction signal is calculated based on a mean value, a standard deviation, an appearance probability of the predetermined bit sequence, and a Hamming distance between the predetermined bit sequence pairs.
摘要:
A light irradiation power adjusting method includes a first recording step, a first reproducing step, a first measuring step, a bias power determining step and a recording power determining step. In the first recording step, an adjustment pattern is recorded to an optical information recording medium while fixing a recording power to a predetermined first power value and while changing a bias power among a plurality of second power values within a predetermined range. In the first reproducing step, the recorded adjustment pattern is reproduced so as to generate a reproduction signal. In the first measuring step, asymmetry values corresponding to the plurality of second power values are measured. In the bias power determining step, an optimum bias power value is determined based on the asymmetry values. In the recording power determining step, an optimum recording power value is determined based on the optimum bias power value.
摘要:
A recording strategy for specifying an output waveform of a laser beam to be applied to a recording layer of an information recording medium is adjusted by the following recording strategy adjusting method. The recording strategy adjusting method includes a base strategy determining step of determining a basic recording strategy; a first top pulse width setting step wherein the shortest mark in a pattern row formed on the recording layer of the information recording medium is specified after the base strategy determining step, and the width of a top pulse, i.e., a pulse for recording the shortest mark, is set; and a step of adjusting a power, including a recording power and a bias power, for recording.