Patents by Inventor Tsuneo Fujiwara
Tsuneo Fujiwara 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).
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Publication number: 20030002407Abstract: A reproduction power control device includes: an adapter/equalizer for adapt and equalizing a digital reproduction signal to a predetermined frequency characteristic so a post-equalization reproduction signal; and a reproduction power control unit for, based on an equalization amount in the adaptation and equalization by the adapter/equalizer, detecting an error between a current reproduction power and an optimal reproduction power and controlling a reproduction power of laser light so as to bring the error closer to 0. In this manner, it becomes possible to offer a reproduction power control method, a reproduction power control device, and a record reproducing device incorporating the same, capable of reproduction power control without reducing the user area on a recording medium.Type: ApplicationFiled: June 28, 2002Publication date: January 2, 2003Applicant: Sharp Kabushiki KaishaInventor: Tsuneo Fujiwara
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Publication number: 20020126598Abstract: A phase correction circuit includes a phase control data generation circuit which judges whether or not the present sector is a leading sector in an ECC block, which is the minimum recording unit in a magneto-optical disk, and generates phase control data by referring to a phase difference data of a previous sector when the present sector is not the leading sector, based on a phase difference detected by a phase difference detection circuit; and a phase control circuit for controlling the phase of a channel clock based on the output of the phase control data generation circuit. With this structure, it becomes possible to provide the phase correction circuit for a disk reproduction device which can generate a sampling clock even when there is a flaw, etc. in a fixed pattern area of the magneto-optical disk, by making a correction so as to avoid or reduce influence by the flaw, etc., and to provide the disk reproduction device using the circuit.Type: ApplicationFiled: January 14, 2002Publication date: September 12, 2002Applicant: Sharp Kabushiki KaishaInventor: Tsuneo Fujiwara
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Publication number: 20020047761Abstract: A breaking mechanism includes a latch receiver engaging a latch to allow a movable contact shoe to be closed, and a tripping device for rotationally driving the latch receiver to disengage the latch to open the movable contact shoe. An engaging surface of the latch engaging the latch receiver is formed as a projecting circular surface, whereas an engaging surface of the latch receiver engaging the projecting circular surface is formed as a recessed circular surface having a radius of curvature greater than that of the projecting circular surface. The center of the curvature of the recessed circular surface coincides with the axis of a support shaft supporting the latch receiver. The loads causing a tripping device to drive the latch receiver do not change even if the location of an engaging point is changed.Type: ApplicationFiled: October 22, 2001Publication date: April 25, 2002Inventors: Kentaro Toyama, Naoshi Uchida, Tatsunori Takahashi, Seiichi Suzuki, Tsuneo Fujiwara, Yoshinobu Hamada, Nobuhiro Sekine, Yoshimi Jumonji, Toshizo Kaihoku
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Patent number: 6282163Abstract: Address information indicative of a certain recording/reproduction position is recorded twice (first address, second address) in an optical disk. Second phase control means makes sampling timings for digitizing the first address have optimal phases. Third phase control means makes sampling timings for digitizing the second address have optimal phases. The second and third phase control means are formed with different circuits, respectively.Type: GrantFiled: September 29, 2000Date of Patent: August 28, 2001Assignee: Sharp Kabushiki KaishiInventor: Tsuneo Fujiwara
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Patent number: 5729517Abstract: A clock extracting section generates a first clock synchronized with a reproducing signal, and a second clock with a frequency twice a frequency of the first clock. An AD converter quantizes the reproducing signal at timing of the second clock. A data classifier classifies the quantized data into two quantized data streams with a period of the first clock. Each equalizer equalizes the two quantized data streams to (1,1) and (1,2,1) partial response characteristics. Each branch metric arithmetic unit calculates a corresponding branch metric respectively. A synthesizer calculates a sum of them so as to generate a synthetic branch metric. An ACS circuit and a data decoding section Viterbi-decode data according to the synthetic branch metric. As a result, even if an SN ratio is lowered by increase in interference between codes and a noises at the time of recording at high density, an error of decoded data can be decreased.Type: GrantFiled: October 28, 1996Date of Patent: March 17, 1998Assignee: Sharp Kabushiki KaishaInventors: Tsuneo Fujiwara, Tomiyuki Numata
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Patent number: 5675569Abstract: A recorded signal reproduction circuit in an optical disc information reading and recording apparatus converts a recorded signal recovered from an optical disc to PR (1, 2, 1) characteristics through a equalizer circuit, digitizes it through an A/D converter and at the same time also generates a clock signal synchronized in phase with the equalizer circuit output signal by using a binary edcoder circuit and a PLL circuit. This clock signal is then provided to an A/D converter as the sampling clock. The A/D converter output signal is then decoded to the original channel bit stream based on the clock signal. Because the equalizer circuit output signal is provided to both the binary encoder/PLL circuit and the A/D converter together, additional circuity for converting signals into a binary series of pulses is unnecessary and reduction of circuit scale is possible.Type: GrantFiled: December 5, 1995Date of Patent: October 7, 1997Assignee: Sharp Kabushiki KaishaInventors: Takeshi Yamaguchi, Tsuneo Fujiwara, Hiroshige Hirajima
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Patent number: 5673046Abstract: An A/D conversion circuit for use in an information reproduction apparatus, includes an envelope generator for extracting an upper-side envelope signal and a lower-side envelope signal from a reproduced signal read out from a recording medium, and an A/D converter for converting the reproduced signal into digital data by using a reference voltage that is obtained from a difference between an upper-side reference voltage and a lower-side reference voltage. In the analog-to-digital conversion circuit, the upper-side reference voltage is set to the level of the upper-side envelope signal, while the lower-side reference voltage is set to the level of the lower-side envelope signal. With this arrangement, the difference between the level of the upper-side envelope signal and the level of the lower-side envelope signal fluctuates together with an amplitude fluctuation component and a low-frequency superimposed component in a fluctuation of the reproduced signal.Type: GrantFiled: August 23, 1994Date of Patent: September 30, 1997Assignee: Sharp Kabushiki KaishaInventors: Hiroshige Hirajima, Hiroshi Fuji, Tsuneo Fujiwara
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Patent number: 5166838Abstract: A digital signal reproduction apparatus includes a first differential circuit for differentiating a reproduction signal reproduced from a recording medium. This differential circuit outputs a first order differential signal. A second differential circuit differentiates the first order differential signal of the reproduction signal and outputs a second order differential signal. A comparator compares the second order differential signal with a predetermined level to produce a window signal. A peak detecting circuit detects zero-cross points in the first order differential signal and outputs a peak detecting signal. A gate gates the peak detecting signal with the window signal to output a reproduction data signal.Type: GrantFiled: March 26, 1990Date of Patent: November 24, 1992Assignee: Sharp Kabushiki KaishaInventors: Hiroshi Fuji, Takeshi Yamaguchi, Kunio Kojima, Toshihisa Deguchi, Shigeo Terashima, Tsuneo Fujiwara
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Patent number: 5107472Abstract: A track access operation system for an optical recording and reproducing apparatus using a medium having a plurality of guide grooves and ID sections utilized for identifying a particular guide groove. The intensity of reflected light and transmitted light from each of a plurality of light beams projected on the recording medium is monitored for determining the location of the beam on the disk. The system is designed such that at least either the plurality of light beams or the plurality of ID sections of the guide grooves are so arranged such that more than half of the light beams or more than half of the ID sections do not overlap in a parallel direction along the guide grooves whereby the number of light beams simultaneously projected on the ID sections is limited to less than half of the total number of light beams projected on the recording medium.Type: GrantFiled: July 5, 1989Date of Patent: April 21, 1992Assignee: Sharp Kabushiki KaishaInventors: Tsuneo Fujiwara, Masaru Nomura, Toshihisa Deguchi, Kunio Kojima, Takeshi Yamaguchi
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Patent number: 5056076Abstract: A method of controlling the rotational velocity of an information recording disk having one or more tracks in which patterns and marks are formed, the marks including at least one specific pattern having a predetermined length, which method comprises: measuring a time during which each of the patterns passes; detecting each of the marks on the basis of the values of the measured times; and controlling the rotational velocity of the disk on the basis of the measured time of the specific pattern of the detected mark, thereby making the linear velocity of the detected mark constant.Type: GrantFiled: April 10, 1990Date of Patent: October 8, 1991Assignee: Sharp Kabushiki KaishaInventors: Kentaroh Tsuji, Hiroshi Fuji, Tomiyuki Numata, Tsuneo Fujiwara, Shigeo Terashima
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Patent number: 5048004Abstract: A recording and reproducing device providing control data recording area on erasable type optical recording medium wherein control data are recorded thereof, characterized in that there is provided a control data recording area forming device for forming control data recording areas having more than two control recording blocks which in turn have more than one recording unit. The control data can be recorded independently. A control data updating device records new control data in the control data recording blocks which were the ones not previously being updated with control data, thereby allowing this device to minimize damage caused by electrical power failure.Type: GrantFiled: April 19, 1989Date of Patent: September 10, 1991Assignee: Sharp Kabushiki KaishaInventors: Toshihisa Deguchi, Takeshi Yamaguchi, Shigemi Maeda, Takashi Iwaki, Tsuneo Fujiwara, Shigeo Terashima
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Patent number: 5018120Abstract: An optical disc medium indexing system having a plurality of elongated parallel tracks wherein each track contains a nonerasable index portion located in less than a single frame. The index portions are formed on the substrate of the disc by a plurality of indentations representing the absolute address of each track on the disc recorded in a multiplex format. Each index portion containing information on the mark, track number and CRC. The disc is constructed so that information may be recorded on the entire surface of the medium including the indexed portions.Type: GrantFiled: December 15, 1988Date of Patent: May 21, 1991Assignee: Sharp Kabushiki KaishaInventors: Kentaroh Tsuji, Tsuneo Fujiwara, Hiroshi Fuji, Shigeo Terashima, Tomiyuki Numata
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Patent number: 5010540Abstract: An apparatus for recording and reproducing information on and from an optical disk includes a first control for producing a first control signal for controlling the rotational speed of a rotational driving apparatus, on the basis of the detected radial position; a judging apparatus which judges whether or not the reproduced signals are reproduced from a recorded region of the optical disk; a second control for producing a second control signal for controlling the rotational speed of the rotational driving apparatus, on the basis of the signals reproduced from the disk; and a switch apparatus which switches the circuit so that the rotational driving apparatus is controlled by the first control signal when the reproduced signals are not reproduced from a non-recorded region, and controlled by the second control signal when the reproduced signals are reproduced from a recorded region.Type: GrantFiled: July 29, 1988Date of Patent: April 23, 1991Assignee: Sharp Kabushiki KaishaInventors: Hiroshi Fuji, Tsuneo Fujiwara, Takashi Iwaki, Tomiyuki Numata, Kentaroh Tsuji, Shigemi Maeda, Takeshi Yamaguchi, Kunio Kojima, Toshihisa Deguchi, Shigeo Terashima
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Patent number: 4993012Abstract: A magneto-optic record signal processing system uses a linearly polarized light beam to be projected onto a magneto-optic medium and a recorded signal is reproduced by analyzing the polarized conditions of a reflected light beam from the medium. This processing system also includes a recording face identifying device for determining the recording face of the magneto-optic record medium. To determine the recording face, an initialized area projecting device projects a light beam onto an initialized area of a magneto-optic record medium. A transducing circuit then converts a slant in a polarization plane of a reflected light beam from the initialized area into a light intensity. A photo-detector detects the light intensity outputted from the transducing means and a comparator compares the output from the photo-detector with a reference level to determine the magnetization of the recording face.Type: GrantFiled: June 3, 1988Date of Patent: February 12, 1991Assignee: Sharp Kabushiki KaishaInventors: Hiroshi Fuji, Tomiyuki Numata, Tsuneo Fujiwara, Kentaroh Tsuji
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Patent number: 4954903Abstract: A digital signal reproduction apparatus includes a first differential circuit for differentiating a reproduction signal reproduced from a recording medium. This differential circuit outputs a first order differential signal and second differential circuit differentiates the first order differential signal of the reproduction signal and outputs a second order differential signal. A comparator compares the second order differential signal with a predetermined level to produce a window signal. A peak detecting circuit detects zero-cross points in the first order differential signal and outputs a peak detecting signal. A gate gates the peak detecting signal with the window signal to output a reproduction data signal.Type: GrantFiled: September 19, 1988Date of Patent: September 4, 1990Assignee: Sharp Kabushiki KaishaInventors: Hiroshi Fuji, Takeshi Yamaguchi, Kunio Kojima, Toshihisa Deguchi, Shigeo Terashima, Tsuneo Fujiwara
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Patent number: 4868922Abstract: A data modulation/demodulation system reproducing data that is divided and recorded in a plurality of blocks on a recording medium. The data modulation/demodulation system utilizes the steps of modulating the data by adding specified data bit patterns to the data bits of each block and reproducing the data which have been obtained by adding specified code bit patterns. The bit rows are independently demodulated by demodulation clocks which differ in phase. The demodulation bit pattern of the above code bit pattern which was added at the time of recording and the bit pattern which was demodulated by the different modulation clocks are compared with each other to determine which data is wrong. The correct demodulated data is selected according to this comparison and transmitted.Type: GrantFiled: January 30, 1987Date of Patent: September 19, 1989Assignee: Sharp Kabushiki KaishaInventors: Kentaro Tsuji, Tsuneo Fujiwara, Shigemi Maeda, Taeshi Yamaguchi, Toshihisa Deguchi, Shozou Kobayashi
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Patent number: 4785252Abstract: A waveform processing circuit includes a switching circuit having first and second inputs and one output. The first input receives head portions and data portions contained in a reproduced signal from an optical head. The second input receives a level signal representing the level of the head portion or the level of the signal carrying the head portion. The switching circuit is switches between a first state in which the first input and the output are connected, and a second state in which the second input and the output are connected. A control signal producer produces a first control pulse indicating the presence of the data portion. The first control pulse is applied to the switching circuit for actuating the switching circuit to establish the first state when the first control pulse is present, and to establish the second state when the first control pulse is not present, so that the switching circuit continuously produces the signal having a level within the range of the head portion.Type: GrantFiled: October 8, 1986Date of Patent: November 15, 1988Assignee: Sharp Kabushiki KaishaInventors: Hiroshi Fuji, Takashi Iwaki, Tsuneo Fujiwara, Toshihisa Deguchi, Shozou Kobayashi