Hitachi, Ltd.

Shoichi Miyazawa

Terumi Takashi

Eisaku Saiki

Hitoshi Ogawa

Motoyasu Tsunoda

Ryutaro Horita

Yasunori Kaneda

Shinichi Kojima

Yukari Katayama

Tsuguyoshi Hirooka

Seiichi Mita

Kunio Watanabe

Katsuhiro Tsuneta

Akira Kojima

Tsuneo Hirose

Shintaro Suzumura

Masatoshi Nishina

Yukari Nagashige

Kouji Shida

Akira Uragami

Akihiko Hirano

Takashi Nara

Katsumi Yamamoto

Masashi Mori

Ryushi Shimokawa

Kazutoshi Ashikawa

Takashi Oeda

Naoki Satoh

Yoshiju Watanabe

Yasuhide Ouchi

Kenichi Hase

Yosuke Hori

Toshihiro Nitta

Hideki Miyasaka

Koji Shida

Tomoaki Hirai

Satoshi Minoshima

Naoto Matsunami

Minoru Yoshida

Hiroshi Kimura

Kazuo Shigematsu

Kiyoshi Honda

Takushi Nishiya

Shuji Ohno

Kazutosi Ashikawa

A magnetic recording and reproducing apparatus includes a R/W signal processor having a write data generator arranged to be of an interleave system and transmitting/receiving data to/from the R/W amplifier via a plurality of signal lines. In addition, the R/W amplifier has a compound circuit provided for the write data of the interleave system from the R/W signal processor and is formed as an integrated circuit, moreover, a &frac12; prescaler is provided at the output of the write data generator, making transmitting and receiving write data in NRZI CODE.

Magnetic recording and reproducing apparatus and semiconductor integrated circuit for use in the same comprising a read/write signal processor having an interleave write data generator

A signal processing circuit for a magnetic recording/reproducing apparatus, including at least an AGC, a PLL, a LPF, an equalizer circuit and a detection circuit, wherein a coefficient compensation circuit is formed by defining a constitution of the equalizer circuit, an error detection circuit is provided which operates by receiving input from the detection circuit, and the LSI is formed by a plurality of analog and digital chips, and the analog and digital chips are connected by current-output type D/A converters connected to at least the AGC and the PLL.

Signal processing circuit and information recording/reproducing apparatus using the same, and method for optimizing coefficients of equalizer circuit

A signal processing device for analog-to-digital converting a burst signal has a feature of selecting a data bus to notify a disk control device of a conversion result via an NRZ data bus. The disk control device stores the result of the analog-to-digital conversion of the servo positional signal. The positional signal of a head of the disk device is digitized in a R/W channel. Sampling for digital conversion is performed in only a window which is defined only in the vicinity of peaks of the positional signal. The values of peaks which are obtained by sampling are averaged by an averaging circuit. This enables the influence of noise occurred outside of the window to be eliminated. Although the noise in the window is sampled, its adverse influence is suppressed by the averaging processing.

Disk device and method of generating signal representing head

A magnetic recording and reproducing apparatus includes a read/write signal processor having a write data generator arranged to be of an interleave system and transmitting/receiving data to/from the read/write amplifier via a plurality of signal lines. In addition, the read/write amplifier has a compound circuit provided for the write data of the interleave system from the read/write signal processor and is formed as an integrated circuit, moreover, a 1/2 prescaler is provided at the output of the write data generator, transmitting and receiving write data in Non-Return-To-Zero-Interleave CODE.

Magnetic recording and reproducing apparatus and a read/write amplifier having a signal transmission system with high speed of data write signal

A signal processing device for analog-to-digital converting a burst signal has a feature of selecting a data bus to notify a disk control device of a conversion result via an NRZ data bus. The disk control device stores the result of the analog-to-digital conversion of the servo positional signal. The positional signal of a head of the disk device is digitalized in a R/W channel. Sampling for digital conversion is performed in only a window which is defined only in the vicinity of peaks of the positional signal. The values of peaks which are obtained by sampling are averaged by an averaging circuit. This enables the influence of noise occurred outside of the window to be eliminated. Although the noise in the window is sampled, its adverse influence is suppressed by the averaging processing.

A magnetic disk recording and reproducing apparatus comprising a unit for inserting an error correcting code related to control information into said control information on data; a recording control unit for recording in a plurality of sectors formed by dividing the recording area of a magnetic disk, each sector having an ID area for recording said control information and a data area, provided adjacent to and behind said ID area, for recording said data; and a error correcting unit for correcting said control information of said ID area by said error correcting code before data is read from said data area corresponding to said ID area or data is recorded in said data area corresponding to said ID area.

Method and apparatus for recording and reproducing disk-type recording medium with dual head including reading head and writing head having offset cores

A disk type recording and reproducing apparatus includes a disk type recording medium having a plurality of tracks and having stored on each of the plurality of tracks a position signal indicating positions on the tracks; a drive section for rotating the disk type recording medium; a dual head separately incorporating a reading head for reading from the disk type recording medium and a writing head for writing into the disk type recording medium; a head drive section for moving the dual head; means for controlling the head drive section by a controlled variable in compliance with a position signal read from the disk type recording medium using an object track and the reading head; and memory means for storing quantity information used to correct the controlled variable of the means for controlling the head drive section. The means for controlling the head drive section, at least in a writing operation, obtains the controlled variable of the head drive section according to the position signal read from the disk type recording medium using the object track and the reading head and the quantity information stored in the memory means.

A signal processing device having a feature of analog-to-digital converting a burst signal has a feature of selecting a data bus to notify a disk control device of a conversion result via an NRZ data bus. The disk control device stores the result of the analog-to-digital conversion of the servo positional signal. The positional signal of a head of the disk device is digitalizes in a R/W channel. Sampling for digital conversion is performed in only a window which is defined only in the vicinity of peaks of the positional signal. The values of peaks which are obtained by sampling are averaged by an averaging circuit. This enables the influence of noise occurred outside of the window to be eliminated. Although the noise in the window is sampled, its adverse influence is suppressed by the averaging processing.

Signal processing apparatus and a disk control apparatus, with head positioning control based on digitized servo data

A disk type recording and reproducing apparatus includes a disk type recording medium, and a dual head including a reading head and a writing head. A center of the core of the reading head is shifted in the radial direction of the disk type recording medium relative to a center of the core of the writing head. The disk type recording medium has a plurality of recording tracks each having a plurality of sectors. Each of the sectors has an ID division provided ahead of a data division disposed in the circumferential direction of the disk type recording medium. The ID division has recorded therein identification information identifying the sector. A center line of the ID division is shifted in the radial direction of the disk type recording medium relative to a center line of the data division by a distance equal to a distance by which the center of the core of the reading head is shifted in the radial direction of the disk type recording medium relative to the center of the core of the writing head. The data division has identification information identifying the sector stored in a position ahead of data to be recorded and reproduced.

Method and apparatus for recording and reproducing disk-type recording

The recording and reproducing apparatus comprises an Small Computer System Interface (SCSI) controller, an optical disc device, a magnetic disc device, a disc controller which controls the optical disc device and the magnetic disc device, connectors which connects directly the optical disc device and the magnetic disc device, and a selector which selects one of the optical disc device and the magnetic disc device. A Copy or Verify command is carried out within the apparatus without an SCSI bus, and data are transferred through the connector. Therefore occupation of the SCSI bus and overhead of the SCSI protocol are eliminated, and the apparatus is miniaturized by common use of the SCSI controller and the disc controller.

Recording and reproducing device for recording and reproducing

A peripheral equipment control LSI interposed between an SCSI bus connected to a main CPU and peripheral equipment such as a file device. The LSI is divided into two major blocks. One block recognizes an SCSI protocol ID signal sent over the SCSI bus. The other block generates a signal that causes the other block to leave a sleep state (low power dissipation mode). In a state in which a command is awaited from the main CPU, the peripheral equipment control LSI allows the block containing the ID recognition part to remain active while the other block is kept in the sleep state. On receiving an ID-based selected (access) signal from the main CPU, the LSI detects the start of an access operation and causes the other block to leave its sleep state and to become active.

Peripheral equipment control device

Reproducing apparatus with an A/D (analog-to-digital) converter, which realizes high-accuracy data sampling, high-speed data transfer, low dissipation power and low cost. PR (partial response) processing is performed by receiving encoded signals, delaying the received signals on the basis of a reference clock, and adding the delayed signals and the received signals in analog signal form. The added signals are converted into digital values on the basis of the reference clock by the A/D converter, and Viterbi decoding is performed on the basis of the converted digital values. Owing to the PR processing which is performed at a stage preceding the A/D converter, a frequency band for the A/D conversion can be lowered, and hence, the high-accuracy data sampling is permitted.

Decoder circuitry with PRML signal processing for reproducing apparatus

Signal processing circuit and information recording/reproducing

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

Apparatus for recording and/or reproducing user data recorded on a record medium. The apparatus includes record encoder for converting original user data into encoded user data of a predetermined record code and an error correcting code generator for generating original error correcting code data for correcting an error with respect to the encoded user data. A write unit records the encoded user data and the error correcting code on the record medium. A read unit reads the recorded data and the reproduced data is error corrected so as to provide the original user data.

Apparatus and method for error correction

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Yokohama, Japan

Shoichi Miyazawa