摘要:
A recording/reproduction apparatus, comprising a first recording section for recording test information onto a medium using at least one recording power, a reproduction section for reproducing at least one test signal indicating the test information from the medium, and a second recording section for recording information onto the medium using one of the at least one recording power. The reproduction section comprises a decoding section for performing maximum likelihood decoding of the at least one test signal and generating at least one binary signal indicating a result of the maximum likelihood decoding, a calculation section for calculating a reliability of the result of the maximum likelihood decoding based on the at least one test signal and the at least one binary signal, and an adjustment section for adjusting a recording power for recording the information onto the medium to the one recording power based on the reliability.
摘要:
An information storage medium according to the present invention is adapted for multiple different writing speeds and stores in advance writing conditions associated with each of the multiple writing speeds. The writing conditions include: a recording-power-related parameter and a write-waveform-related parameter, which are associated with each particular writing speed to perform a write operation at the particular writing speed; and another recording-power-related parameter for performing a write operation at a different writing speed other than the particular one using the recording-power-related parameter for performing the write operation at the particular writing speed.
摘要:
A reproduction signal evaluation method according to the present invention includes a step of generating a binary signal from an information recording medium on which a data sequence including marks and spaces in combination is recordable, using a PRML signal processing method from a signal obtained by reproducing the data sequence; and a differential calculation step of calculating a differential metric using a first state transition path having a maximum likelihood and a second state transition path having a second maximum likelihood, and a reproduction signal, the first state transition path and the second state transition path being obtained based on the binary signal. In a pattern including a shortest mark and a shortest space adjacent before or after the shortest mark, a shift amount of an edge of the shortest mark is obtained from a differential metric calculated regarding one of a first pattern in which a space adjacent to the shortest mark and not adjacent to the shortest space is longer than the shortest space; and a second pattern in which a mark adjacent to the shortest space and not adjacent to the shortest mark is longer than the shortest mark.
摘要:
The present invention has an object of evaluating a recording and reproduction signal quality of a high density information recording medium by providing an index representing, in a detection signal including a plurality of pieces of edge shift information, how each edge is shifted. A signal evaluation method, usable for an information recording medium having a data sequence including a mark and a space located alternately, for generating a binary signal from a signal obtained by reproducing the data sequence using a PRML signal processing method and evaluating a likelihood of the binary signal, includes a differential metric calculation step of calculating, from the binary signal, a differential metric which is a difference of a reproduction signal from a first state transition matrix having a maximum likelihood and a second state transition matrix having a second maximum likelihood; and a step of classifying the differential metric to any of a plurality of data patterns each including at least one mark and at least one space. The data pattern classification to any of the plurality of data patterns is performed using a combination of a length of a first mark included in the data sequence and a length of a first space adjacently located immediately previous or immediately subsequent to the first mark, and is further performed using a length of a second mark which is not adjacent to the first mark and located adjacent to the first space; and thus a reproduction signal quality of the information recording medium is evaluated.
摘要:
A reproduction signal evaluation method for evaluating quality of a reproduction signal reproduced from an information recording medium based on a binary signal generated from the reproduction signal using a PRML signal processing system, includes: a pattern extraction step of extracting, from the binary signal, a specific state transition pattern which has the possibility of causing a bit error; a step of computing a differential metric based on the binary signal; an extraction step of extracting the differential metric which is not greater than a predetermined signal processing threshold; a step of determining a mean value of the differential metrics which are not greater than the signal processing threshold and extracted in the extraction step; a standard deviation computing step of determining a standard deviation which corresponds to an error rate predicted from the mean value; and an evaluation step of evaluating a quality of the reproduction signal using the standard deviation.
摘要:
A signal evaluation method according to the present invention is a method for evaluating a read signal, retrieved from an information recording medium, based on a binarized signal generated from the read signal by a PRML method. The method includes the steps of: detecting the patterns of multiple paths associated with the binarized signal and merging into the same state; getting the ideal value of a correct pattern associated with the binarized signal and that of an erroneous pattern that is similar to, but different from, the correct pattern; calculating the difference between a distance from the ideal value of the correct pattern to the read signal and a distance from that of the erroneous pattern to the read signal; calculating, based on the difference, an expected error rate for each predetermined group of patterns by the PRML method; and calculating a standard deviation that is associated with a total error rate, which is obtained by adding together the error rates of the predetermined groups of patterns, and that is used for evaluating the read signal.
摘要:
A signal evaluation method according to the present invention is a method for evaluating a read signal, retrieved from an information recording medium, based on a binarized signal generated from the read signal by a PRML method. The method includes the steps of: detecting the patterns of multiple paths associated with the binarized signal and merging into the same state; getting the ideal value of a correct pattern associated with the binarized signal and that of an erroneous pattern that is similar to, but different from, the correct pattern; calculating the difference between a distance from the ideal value of the correct pattern to the read signal and a distance from that of the erroneous pattern to the read signal; calculating, based on the difference, an expected error rate for each predetermined group of patterns by the PRML method; and calculating a standard deviation that is associated with a total error rate, which is obtained by adding together the error rates of the predetermined groups of patterns, and that is used for evaluating the read signal.
摘要:
A recording control apparatus includes a waveform rectification section for receiving a digital signal generated from an analog signal representing information reproduced from an information recording medium, and rectifying a waveform of the digital signal; a maximum likelihood decoding section for performing maximum likelihood decoding of the digital signal having the waveform thereof rectified, and generating a binary signal representing a result of the maximum likelihood decoding; a reliability calculation section for calculating a reliability of the result of the maximum likelihood decoding based on the digital signal having the waveform thereof rectified and the binary signal; and an adjusting section for adjusting a shape of a recording signal for recording the information on the information recording medium based on the calculated reliability.
摘要:
A most probable path is selected from a number n (where n≧2) of paths of state transitions occurring from a first state Sk−j (where k≧3 and j≧2) at a time k−j into a second state Sk at a time k. The method includes the steps of detecting predetermined combinations of the first and second states Sk−j and Sk defining the n probable paths in a predetermined period j between the times k−j and k, and evaluating the reliability of a read signal, decoded in the period j, by |Pa−Pb|. Pa and Pb indicate the probabilities of state transition of first and second state transition paths in the period j. The first and second state transition paths are estimated to be the most probable and the second most probable, respectively, among the n probable paths defined by the combinations detected.
摘要:
An information processing device (225) is a device for processing specific information recorded to a recording medium (100), and has a characteristic identification unit (204) and a processing unit (226). The characteristic identification unit (204) identifies the reflection characteristic of the recording medium (100). The processing unit (226) processes the specific information recorded to the recording medium (100) according to the identified reflection characteristic. The reflection characteristic is either a first characteristic such that the reflectance of light reflected by a recorded region of the recording medium (100) (referred to as first reflectance) is greater than the reflectance of light reflected by an unrecorded region of the recording medium (100) (referred to as second reflectance), or a second characteristic such that the first reflectance is less than the second reflectance.