Hitachi, Ltd.

Hitachi Global Storage Technologies Japan, Ltd.

Other

Hitachi Video and Information System, Inc.

Takushi Nishiya

Takashi Nara

Motohisa Funabashi

Seiichi Mita

Hideyuki Yamakawa

Takatoshi Kato

Terumi Takashi

Hiroshi Ide

Kazuo Kera

Mikio Yoda

Shintaro Suzumura

Yoichi Uehara

Nobuaki Nakai

Hiroshi Kimura

Makoto Shioya

Tatsuya Hirai

Yoshiju Watanabe

Hitoshi Ogawa

Shoichi Miyazawa

Akihiko Hirano

Ryushi Shimokawa

Kazutoshi Ashikawa

Hiromitsu Kurisu

Kiyomi Mori

Shoichi Miyazawa, Deceased

Soichi Isono

Tomoki Oura

Kyoko Tsukano

Masahiro Oba

In order to generate a sampling clock having a higher accuracy, a synchronous signal generating circuit is provided with a phase error detector, detecting a phase error of a read out signal digitized on the basis of FDTS algorithm, and a VCO, controlling an oscillation frequency on the basis of a phase error detected by the phase error detector, to generate a synchronous signal by the VCO. On the basis of the synchronous signal generated by the synchronous signal generating circuit, an ADC digitizes the read out signal. The digitized read out signal is then converted to binary data by a detection circuit.

Apparatus for information recording and reproducing

Defect management information of a disk apparatus is read efficiently. Pieces of defective track information, which each indicate existence of defective tracks for a group of a plurality of tracks, are stored being associated with physical track numbers. And, pieces of defect information on defective tracks are stored in predetermined groups. Further, pieces of pointer information that indicate start addresses of storage address for the above-mentioned predetermined groups are stored. When a processing means receives an instruction of read or write to a track of a storage medium, the processing means refers to a piece of defective track information based on the above-mentioned addresses. When existence of a defective track is indicated, the processing means refers to a piece of pointer information corresponding to the group relating to the referred piece of defective track information. Then, the processing means sequentially accesses the pieces of defect information from the storage area indicated by the above-mentioned piece of pointer information, to detect a piece of defect information of the track as the object of the instruction. Then, the processing means performs defect processing on the defective track based on the defect information detected.

Disk apparatus

The computer system includes a host system, a recording medium, and a digital signal decoder connected to the host system and the recording medium. The digital signal decoder receives M-bit data and generates an N-bit code word from the M-bit data. The number of consecutive bits of 1 in the code word is not larger than a first predetermined number K, and the number of consecutive bits of 0 is not larger than a second predetermined number L. When data is recorded/reproduced by a method such as NRZI (Non-Return to Zero Inverted), or the like, there is a defect in that the number of transitions of data is larger in a code with a high data encoding rate, and the run length of zero is long thereby increasing the data decoding error rate with the recording/reproducing of data. In the digital signal decoder according to the present invention, any code word includes at most 3 consecutive bits of 1, and at most 11 consecutive bits of 0, so that the data decoding error rate can be reduced.

Data encoding method for digital data recording and data recording system using the same

A transconductance control circuit is composed of a replica transconductance amplifier and resistance, a reference voltage source, first selectors, a differential amplifier, a voltage-current translate circuit with characteristics equal to the transconductance amplifier which constitutes analog filters. A first switch of the first selectors is connectable for the reference voltage source, and every constant period is made to connect it using clocks at the reference voltage source. A second switch of second selectors is connectable for plural capacitors, and every constant period is made to connect it using clocks at the capacitors.

Time sharing analog filters control method and magnetic disk system

A calculation concerning the input of a signal is removed from a branch metric calculation processing on a trellis diagram of an extended partial response class, and the calculation of branch metrics and the selection of survivor paths can be carried out by the subtraction of the survivor paths and the comparison of constants.

Digital signal decoding apparatus and a decoding method used therein

A system for reproducing data recorded on a magnetic recording medium at high density is provided as a simple configuration. Quadripartite reproduction data is output from a Viterbi detection circuit to an adder, which then subtracts the quadripartite reproduction data from a signal before PR4-ML method data determination. An adder is used to perform a (1+D) process for the result. An error signal pattern detection circuit performs maximum likelihood estimation for an PR4-ML method detection error. Further, when a detected determination error matches an actual reproduction data string, a data correction circuit corrects the reproduction data string.

System for reproducing high-density magnetic record data with viterbi

A playback signal processing circuit for reducing decode errors and enabling high-density digital magnetic recording and a digital magnetic recording reproducing unit using the playback signal processing circuit are provided. An estimated waveform generation circuit uses the decoding result of a PRML channel to generate an ideal playback signal waveform. A subtractor provides a waveform representing a difference between the waveform and an actual playback signal. There is a high probability that error bits will occur at an interval of two or four bits because of the nature of GCR code and maximum-likelihood decoding; in the error state of each bit, one bit is incremented by one with respect to the correct bit value and the other signal bit is decremented by one. From this fact, an error detection circuit discriminates an error difference waveform pattern and an error discrimination circuit detects an error bit interval, whereby an error correction circuit carries out error bit correction.

Digital signal processor, error detection method, and recording medium

A symbolization apparatus which includes a membership function memory unit for storing a membership function used in fuzzy logic processing. In the symbolization apparatus a process condition change pattern is converted into an ambiguous symbol in order to build up a system capable of effecting an inference and decision approximate to a skilled operator against an object process. A process condition value memory is disclosed for holding a measurement of the process condition value and a process operation amount, a control history memory unit for storing operations and values converted into symbolic expressions, control units and a knowledge base for storing the information relating to the casual relations between the process control values and the process conditions. The process control system and a control support system comprise the function of condition identification approximate to that of a skilled operator by the use of the symbolization apparatus.

Symbolization apparatus and process control system and control support

A method and apparatus of a learning type decision support system are provided for improved acquisition of a priori knowledge from the system object and expression of non-linear structures in the object. The system is comprised of a learning module and an executing module for outputting advice and process manipulate command values to system users by receiving input data comprising on-line data and file data. The learning module comprises (1) a symbolized dictionary unit for generating a symbolized dictionary for giving a symbolic name in accordance with a pattern comprised of a combination of the values of the input data by giving examples of a pair of the pattern and the symbolic name; (2) a preprocessing unit for transforming at least a portion of the input data into the symbolic name with reference to the symbolic dictionary generated; and, (3) a model generating unit for determining an unknown parameter contained in a predetermined skeleton model to transform the preprocessed results into desired advice and manipulation command values. The executing module arithmetically processes the input data to output the advice and the manipulation command values by using the symbolized dictionary generated by the learning module and the generated model.

Learning type decision support system

In order to easily identify a pattern of time-series state changes based on measured information so as to facilitate representation of edge portions of an image, features extracted in a form of expansion coefficients of polynomials from the measured information are translated into abstract expressions so as to detect from the measured information significant control information which has not been used in the conventional technology, and features extracted in a form of expansion coefficients from brightness changes in the vicinity of each pixel constituting image data are translated into abstract expression.

Processor for pattern data, measured process information, and image

An apparatus for comparing a data pattern with standard patterns to discriminate the data pattern retrieves vector series of the standard patterns associated with the data pattern. Categorized names are assigned to data of the vector series so as to be respectively associated with elements of the data pattern, thereby determining a similarity degree and a scale factor between the vector series.

Pattern discrimination method and apparatus using the same

Points on a pair of images obtained by imaging an object are finely corresponded in order to precisely measure the three-dimensional position of the object. For this purpose, attractive forces corresponding to features of the images are calculated, and the degree of correspondence between the points on the pair of images is evaluated relying upon the magnitude of the attractive force, in order to determine the corresponding points and to calculate the position of the object relying upon the thus determined corresponding points. Further, an occluded region which contains no corresponding point is detected and is removed, in order to further improve the precision for measuring the position.

Position measuring method

A method of forming a three-dimensional stereo vision is disclosed in which, in order to prevent the erroneous detection of an object point in the conventional method using two image focusing lens systems, three image points of an object point formed by logically and/or physically selecting three image focusing lens systems and three image sensing surfaces from a multiplicity of image points on an image sensing surface by using the fact that a positional relation among three image points of the same object point is similar to the positional relation among the three image focusing lens systems, and the positional information of three selected image points on the image sensing surface is used for obtaining three-dimensional distance information of the object point.

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Machida, Japan

Takushi Nishiya