Patents by Inventor Tohru Sampei

Tohru Sampei 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: 5084786
    Abstract: A helical scan tape apparatus including a first pair of magnetic heads having mutually different azimuth angles disposed on a peripheral face of a rotary drum at an angle interval of 180 degrees so as to oppose each other, a second pair of magnetic heads disposed on of the rotary drum so as to be perpendicular to a disposition direction of the first magnetic heads, a magnetic tape helically wound around the rotary drum so as to extend over an angle of 90 degrees, the tape being moved while the drum is controlled to rotate in synchronism with a reference signal, the first magnetic heads having a wider gap width than a track pitch of tracks recorded on the tape without providing a guard band for enabling azimuth recording of a data signal on the tracks, the data signal being recorded repeatedly into a particular recording area, wherein the first magnetic heads are used substantially for recording and the second magnetic heads are used substantially for reproduction and are positioned with a downward shift in th
    Type: Grant
    Filed: July 27, 1988
    Date of Patent: January 28, 1992
    Assignee: Hitachi, Ltd.
    Inventors: Kazutoshi Konno, Hidehumi Goto, Hiroshi Chiba, Tohru Sampei
  • Patent number: 4796140
    Abstract: A rotary disk including a recording and reproducing sheet, and a hub formed of hard material secured to a central portion of the sheet. The hub comprises a center opening adapted to receive a main spindle of a turntable of disk driving means, two planar surfaces arranged in an intersecting relation to each other and formed on a projecting wall portion of the center opening, and a resilient member located in a position facing the two planar surfaces for pressing the spindle against the two planar surfaces. Even if the recording and reproducing sheet of the rotary disk is a thin magnetic sheet, there is no risk of damage of the sheet. When the rotary disk is set on the turntable, the center of rotation of the rotary disk and the center of rotation of the turntable can be automatically brought into alignment with each other.
    Type: Grant
    Filed: October 27, 1986
    Date of Patent: January 3, 1989
    Assignee: Hitachi, Ltd.
    Inventors: Manabu Wakabayashi, Tohru Sampei, Hiroshi Kanai, Tomiyoshi Satoo, Yosuke Nagano, Takeo Sonobe, Isao Utsugi
  • Patent number: 4613920
    Abstract: A magnetic head suitable for use in a magnetic disk. In a magnetic head in accordance with the present invention, a read/write head and an erase head are placed side by side in the rotation direction of the magnetic disk. A gap in the read/write head is placed at a distance of l from a pair of gaps in the erase head. In addition, the read/write gap in the read/write head is deviated by a distance L in the external circumference direction with respect to a pair of erase gaps in the erase head.
    Type: Grant
    Filed: June 8, 1983
    Date of Patent: September 23, 1986
    Assignee: Hitachi, Ltd.
    Inventors: Shigemitsu Higuchi, Kazutoshi Konno, Tohru Sampei
  • Patent number: 4551777
    Abstract: A tracking servo system for a magnetic recording and reproducing apparatus uses a flexible magnetic disk having thereon at least first, second and third tracks each of which includes a data track portion and a pair of servo track portions located on both sides of the data track portion. Tracking signals having different frequencies are recorded on the first, second and third servo track pairs. Servo and data heads are formed in a unitary structure. When the data head records an information signal on the second data track portion or reads out the recorded information signal therefrom, the servo head reads out the tracking signals recorded on the first and third servo track portions.
    Type: Grant
    Filed: August 11, 1982
    Date of Patent: November 5, 1985
    Assignee: Hitachi, Ltd.
    Inventors: Tadashi Saito, Shigemitsu Higuchi, Kazutoshi Konno, Tohru Sampei, Kenji Hayashi, Yoshihiko Noro, Manabu Wakabayashi
  • Patent number: 4491958
    Abstract: In a speech synthesizer designed so that natural speech is chopped at constant intervals of time and characteristic parameters of the speech are extracted from the chopped speech and used for synthesis of speech, the number of bits of a characteristic parameter per analytical frame is not changed, but the interval of time of one analytical frame is changed to change the amount of information per unit time, while the time interval of one synthesis frame of the synthesizer is changed with the time interval of one analytical frame so that the time interval of one frame upon analysis and the time interval of one frame upon synthesis are made equal, whereby a single speech synthesizer can handle speech parameters of different amounts of information.
    Type: Grant
    Filed: October 22, 1981
    Date of Patent: January 1, 1985
    Assignees: Nippon Telegraph & Telephone Public Corporation, Hitachi, Ltd.
    Inventors: Kazuhiro Umemura, Tohru Sampei, Kazuo Nakata, Hirokazu Sato, Murakami Kenya, Kiyoshi Intoh
  • Patent number: 4443741
    Abstract: A drive circuit for an electroluminescent (EL) element whose brightness can be changed by changing a voltage or the frequency of the voltage applied to the EL element and can be kept constant by keeping the current flowing through the EL element constant is disclosed. The drive circuit is provided with a drive power source whose output voltage or output voltage frequency is variable by a control signal. The output of the drive power source is supplied to the EL element. The current flowing through the EL element is detected by a current detecting element and a signal related to the detected current is applied as the control signal to the drive power source to subject the EL element to a constant-current drive.
    Type: Grant
    Filed: September 14, 1981
    Date of Patent: April 17, 1984
    Assignee: Hitachi, Ltd.
    Inventors: Katsuyuki Tanaka, Shin-ichi Ohashi, Masakatsu Saito, Tohru Sampei
  • Patent number: 4435832
    Abstract: A speech synthesizer is disclosed with the capability of stretching and compressing the speech time base without changing the pitch of the synthesized speech. One frame of speech is represented during a given time base by LPC parameters which are sampled a constant number of times per frame and stored in memory. Speech is synthesized by fetching each of the stored LPC parameters for each frame and subjecting the parameters to interpolation, synthesizing the interpolated parameters and converting the synthesized parameters to analog format. A decrease in the speed of the reproduced speech is produced by lengthening the time interval of interpolation between the fetching of each of the stored LPC parameters which have been previously stored for each frame. An increase in the speed of the reproduced speech is produced by decreasing the time interval of interpolation between the fetching of each of the stored LPC parameters which have been previously stored in each frame.
    Type: Grant
    Filed: September 30, 1980
    Date of Patent: March 6, 1984
    Assignee: Hitachi, Ltd.
    Inventors: Akihiro Asada, Kazuhiro Umemura, Tadashi Saito, Tohru Sampei
  • Patent number: 4422109
    Abstract: A magnetic recording and reproducing apparatus comprises a source for producing test signals, a variable-gain amplifier, an equalizer, a recording bias generating circuit, a control unit for supplying control signals to the amplifier, equalizer and recording bias generating circuit, a memory and an operating circuit unit.
    Type: Grant
    Filed: June 22, 1982
    Date of Patent: December 20, 1983
    Assignee: Hitachi, Ltd.
    Inventors: Tohru Sampei, Naoya Fujita, Shigemitsu Higuchi, Masamichi Yamada, Kohichi Tomatsuri
  • Patent number: 4422108
    Abstract: A tape recorder comprises, in its signal recording path, a variable gain circuit compensating the sound recording sensitivity of a magnetic tape and two variable equalizers compensating the frequency characteristic of the magnetic tape in the intermediate and high frequency ranges respectively. Reference signals at three different frequencies are successively supplied to the signal recording path to be recorded on the magnetic tape, and the signals of different reference frequencies are successively reproduced from the magnetic tape to be then arithmetically processed so as to optimize the gain of the variable gain circuit and the degree of frequency characteristic compensation by the first and second variable equalizers.
    Type: Grant
    Filed: June 1, 1982
    Date of Patent: December 20, 1983
    Assignee: Hitachi, Ltd.
    Inventors: Tohru Sampei, Naoya Fujita, Shigemitsu Higuchi, Masamichi Yamada, Kouichi Tomatsuri
  • Patent number: 4401971
    Abstract: An alarm device for a vehicle comprises sensors for detecting abnormal states of the vehicle, a logic circuit for receiving the outputs of the sensors and producing one or more alarm speech designation signals and an alarm speech generator responsive to the alarm designation signal. The logic circuit includes a priority circuit for determining the order of precedence of the abnormal states represented by the detection signals on the basis of the degree of emergency, so that the alarm speech is concerned with the most emergent alarm when two or more abnormal states are detected simultaneously. The logic circuit may further include a switch circuit for disabling at least one of the detection signals so that a vehicle driver having taken notice of particular alarms is not disturbed by excessive alarming.
    Type: Grant
    Filed: March 10, 1981
    Date of Patent: August 30, 1983
    Assignee: Hitachi, Ltd.
    Inventors: Tadashi Saito, Tohru Sampei, Akihiro Asada, Yoshihiro Ohta, Syunji Iwasaki, Shigemitsu Higuchi, Hiroshi Ozawa, Yasunari Tanaka
  • Patent number: 4390747
    Abstract: A speech analyzer for extracting spectrum information and pitch information from natural speech wherein an accuracy of pitch extraction is enhanced by sampling pitch at a sampling frequency which is higher than a sampling frequency for analyzing the spectrum information.
    Type: Grant
    Filed: September 26, 1980
    Date of Patent: June 28, 1983
    Assignee: Hitachi, Ltd.
    Inventors: Tohru Sampei, Akihiro Asada, Yoshihiro Ohta, Syunji Iwasaki
  • Patent number: 4168471
    Abstract: A source follower circuit using at least one FET in which an end of a resistor element is connected to the gate terminal of the FET and the other end of the resistor element is connected to a signal source which generates a comparatively large AC input signal. The resistance of the resistor element is determined to be at such a value as to prevent oscillation of the FET which is likely to occur depending on the length of the wiring between the signal source and gate terminal and the length of wiring between the source terminal and a load.
    Type: Grant
    Filed: April 13, 1978
    Date of Patent: September 18, 1979
    Assignee: Hitachi, Ltd.
    Inventor: Tohru Sampei
  • Patent number: 4163197
    Abstract: In a push-pull power amplifier which amplifies an audio-frequency signal supplied thereto and supplies its output signal to a load, a pair of output transistors constituting the push-pull circuit are alternately turned on and off according to the polarity of the input signal. In the power amplifier, current flowing through the current path leading from a DC power source to each of the output transistors includes many harmonic components besides its fundamental wave component. These harmonic components of current are introduced through a stray magnetic field into the signal path in the power amplifier thereby producing distortion of the signal supplied to the load.
    Type: Grant
    Filed: February 16, 1978
    Date of Patent: July 31, 1979
    Assignee: Hitachi, Ltd.
    Inventor: Tohru Sampei
  • Patent number: 4100501
    Abstract: An audio frequency power amplifier wherein an input signal is applied to respective input electrodes of a pair of transistors of the same conductivity type to produce an output signal at an output electrode of one of the pair of transistors. A common electrode of the one transistor is connected with an output electrode of the other transistor and a power from a first D.C. power supply is supplied to the junction thereof through a diode while a power is supplied to a common electrode of the other transistor from a second D.C. power supply having a higher voltage than that of the first D.C. power supply. The other transistor and the diode are alternately rendered conductive and non-conductive in response to the signal level of the input signal, a capacitor is connected to the input electrode of the other transistor, which capacitor is charged during the turn-off of the other transistor whereby the charge is supplied to the other transistor upon turning on of the other transistor to shorten the rise time.
    Type: Grant
    Filed: February 11, 1977
    Date of Patent: July 11, 1978
    Assignee: Hitachi, Ltd.
    Inventors: Harushige Nakagaki, Tohru Sampei, Nobutaka Amada, Tatsuo Baba
  • Patent number: 4068187
    Abstract: An audio- or low-frequency power amplifier comprises a pair of output transistors which are opposite in a conduction type to each other and connected in a complementary push-pull circuit configuration in which an impedance element is connected between the bases of the paired output transistors whose bases are adapted to be applied with an input signal while the output signal of the amplifier is derived from the coupled emitters of the output transistors. The amplifier further includes a current stabilizer transistor having a base-emitter junction across which a fixed bias voltage is applied and a collector, the current from which is supplied to the impedance element thereby to provide a bias voltage for the paired output transistors. A first resistor is connected between the emitter of the current stabilizer transistor and one electrode or pole of a first d.c. power source while a second resistor is connected between the emitter of the current stabilizer transistor and the other pole of the d.c.
    Type: Grant
    Filed: March 16, 1977
    Date of Patent: January 10, 1978
    Assignee: Hitachi, Ltd.
    Inventors: Nobutaka Amada, Tohru Sampei, Akinori Maeda
  • Patent number: 4045744
    Abstract: The same input signal is applied to each of the bases of a pair of amplifying transistors, while an output signal is produced at the emitter of one of the pair of transistors. The collector of the one transistor is connected to the emitter of the other transistor. The junction point between the collector of the one transistor and the emitter of the other transistor is connected through a diode to a first DC power source of low voltage. A second power source of high voltage is connected to the collector of the other transistor, thereby selectively supplying electric power to the one transistor in accordance with the signal level of the input signal. An inductance element is connected in series with the diode to generate a counter electromotive force to prevent a reverse current from flowing through the diode during the cut-off state of the diode, thus providing a highly efficient amplifier with little distortion.
    Type: Grant
    Filed: October 21, 1976
    Date of Patent: August 30, 1977
    Assignee: Hitachi, Ltd.
    Inventor: Tohru Sampei
  • Patent number: 3961280
    Abstract: There is provided an amplifier circuit wherein the changing of power supply voltages is effected in accordance with the amplitude of an input signal. The amplifier circuit comprises an amplifying transistor having its base adapted to receive an input signal and its emitter connected to a load, a switching transistor having its base and emitter connected respectively to the base and collector of the amplifying transistor, a first power source for supplying power to the collector of the switching transistor, and a second power source for generating a voltage lower than the output voltage of the first power source and supplying power to the collector of the amplifying transistor.
    Type: Grant
    Filed: August 23, 1974
    Date of Patent: June 1, 1976
    Assignee: Hitachi, Ltd.
    Inventor: Tohru Sampei