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:
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:
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:
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.
摘要:
An optical disc apparatus according to the present invention includes a recording strategy adjusting section having an initial value setting section; an output level setting section; and a pulse width setting section. The initial value setting section sets initial values of pulse widths and output levels of a laser beam as a basic recording strategy. Also, the output level setting section adjusts output levels of the recording strategy with a plurality of first adjustment laser beams that are outputted by changing the output levels of the basic recording strategy. Also, the pulse width setting section adjusts the output levels of the recording strategy with a plurality of second adjustment laser beams that are outputted by fixing the output levels set by the initial value setting section, and changing the pulse widths of the basic recording strategy.
摘要:
The optical information recording/reproducing unit distinguishes an unrecorded area of a set optical disc (step A100). Thereafter, recording is performed in the unrecorded area under a plurality of recording conditions wherein the recording power is changed with a bias power being constant, to select a recording power providing an optimum reproduced-signal quality (step B100). Subsequently, recording is performed using the selected recording power under a plurality of recording conditions wherein the recording power is fixed onto the selected recording power and the bias power is changed, to select a bias power providing an optimum reproduced-signal quality (step C100). The selected recording power and the selected bias power are set as the recording-use optical irradiation power and bias power, respectively (step D100).
摘要:
In order to evaluate the quality of a signal recorded on an optical recording medium, a target signal is obtained based on a predetermined data string and a predetermined partial response characteristic, and for each clock cycle, an equalization error is calculated that is a difference between the target signal and a signal reproduced each clock cycle. Further, the product of the equalization errors calculated at different times is obtained, and based on the obtained product, the quality of a signal is evaluated.
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.