Patents by Inventor Tetsu Watanabe

Tetsu Watanabe has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5189650
    Abstract: In a magneto-optical signal reproducing apparatus for reading out a signal recorded on a magneto-optical recording medium by an optical pickup device so as to provide a magneto-optical signal which, in turn, is level-discriminated on the basis of a reference level to reproduce data therefrom, the reference level is controlled in accordance with a level of an in-phase signal component provided from the optical pickup device, thereby enabling stable data reproduction.
    Type: Grant
    Filed: November 26, 1990
    Date of Patent: February 23, 1993
    Assignee: Sony Corporation
    Inventors: Tetsu Watanabe, Tamotsu Yamagami, Tetsuji Kawashima
  • Patent number: 5182734
    Abstract: In a magneto-optical recording apparatus, in which light spots are sequentially formed on a magneto-optical disk at the timing of a predetermined reference clock signal while a modulating magnetic field, which is reversed in polarity as a function of record data in synchronism with the reference clock signals, is applied to the disk for magnetically recording the record data thereon; the timing of polarity reversal of the modulating magnetic field with respect to the reference clock signal is delayed as a function of the magnetic and/or temperature characteristics of the magneto-optical disk to permit a magnetized domain to be formed at the correct position with respect to the timing of the reference clock signal.
    Type: Grant
    Filed: February 20, 1990
    Date of Patent: January 26, 1993
    Assignee: Sony Corporation
    Inventors: Tetsu Watanabe, Tetsuji Kawashima, Goro Fujita
  • Patent number: 5170385
    Abstract: A recording medium in which one sector is divided into a plurality of segments and information is recorded in the segments, uses a reproducing method in which information is reproduced optically from this medium. The recording medium has an area in which no embossed pit is formed beforehand comprising at least one segment among a plurality of segments, and embossed pits indicative of the head of the sector which is formed in correspondence to the head position of the sector. Clocks are reproduced by detecting the pit for clock reproduction on the basis of the area in the recording medium in which no embossed pit is formed beforehand. The head position of the sector is detected by detecting whether the pit indicative of the head of the sector is present or not at a timing based on the clock. With this method, the head position of the sector can be detected correctly even if information was recorded by a modulating system in which all signal patterns can exist according to the modulating rule.
    Type: Grant
    Filed: October 25, 1990
    Date of Patent: December 8, 1992
    Assignee: Sony Corporation
    Inventors: Susumu Senshu, Tamotsu Yamagami, Shigeaki Wachi, Tetsu Watanabe
  • Patent number: 4998231
    Abstract: A magneto-optical disk recording apparatus sequentially pulse-drive a plurality of semiconductor laser elements in a time-divisional manner so that spots of light are sequentially formed along a plurality of recording tracks of a magneto-optical disk with clock information recorded in advance along a plurality of recording tracks thereon. A magnetic modulating signal is generated by combining pieces of information desired to be recorded along the plurality of recording tracks so that a modulating magnetic field whose polarity is reversed in accordance with the magnetic modulating signal is applied to the plurality of recording tracks by means of a magnetic head.
    Type: Grant
    Filed: December 8, 1989
    Date of Patent: March 5, 1991
    Assignee: Sony Corporation
    Inventors: Tetsu Watanabe, Hiroshi Ogawa
  • Patent number: 4559568
    Abstract: An apparatus for re-recording a new digital signal in a track on a magnetic record medium which has a previously recorded digital signal in the track, the digital signal being arranged in data blocks each containing a sync signal, a data signal, an error correction code signal, and an error detection code signal, comprises a reproducing circuit which reproduces each digital signal recorded on the magnetic record medium, a code generating circuit which supplies a discriminating code signal for each of the data blocks, and a recording circuit which re-records the new digital signal and the respective discriminating code signals in the track on the magnetic record medium.
    Type: Grant
    Filed: January 19, 1983
    Date of Patent: December 17, 1985
    Assignee: Sony Corporation
    Inventors: Tetsu Watanabe, Masato Tanaka
  • Patent number: 4348699
    Abstract: An apparatus for recording and/or reproducing a serial digitized analog signal controls the transport speed of a recording medium according to the sampling rate employed in digitizing the analog signal to produce a constant data density on the recording medium regardless of the sampling rate selected. The frequency of a fundamental clock signal establishes the sampling frequency during recording. A coded timing signal also recorded on the recording medium includes both a sync signal and a coded identity of the sampling frequency in use. During reproduction, the coded identity of the sampling frequency is used to select the same fundamental clock signal as was used during recording and the reproduced sync signal is phase compared with a reference signal derived from the fundamental clock signal to correspondingly control the speed and phase of transport of the recording medium. The fundamental clock signal may be manually varied during reproduction for pitch control of the reproduced analog signal.
    Type: Grant
    Filed: May 13, 1980
    Date of Patent: September 7, 1982
    Assignee: Sony Corporation
    Inventors: Yoshikazu Tsuchiya, Masato Tanaka, Takenori Sonoda, Tetsu Watanabe, Chiaki Kanai, Nobuhiko Watanabe