Matsushita Electric Industrial Co., Ltd.

Pioneer Electronic Corporation

Kabushiki Kaisha Toshiba

Hitachi, Ltd.

Akira Kurahashi

Toshiyuki Shimada

Kazuhiro Aoki

Noboru Kikuchi

Shinichi Tanaka

Takao Arai

Toshifumi Takeuchi

Yoshiaki Moriyama

Tadashi Kojima

Hisashi Yamada

Koichi Hirayama

Fumihiko Yokogawa

Yasuaki Edahiro

Akinobu Soneda

Fumihiko Pioneer Electronic Corp Yokogawa

Yoshiaki Pioneer Electronic Corp Moriyama

A transmitting method of digital data whereby information data can be reproduced at a high precision. In order to retain digital data in sectors comprising a plurality of sync frames and sequentially transmit, the sync frame is comprised of the sync signal and the run length limited code which satisfies the limitations of the minimum run length and the maximum run length, and the sync signal includes the sync pattern constituted by a bit pattern of a run length that is longer than the maximum run length by onlyT and addition bit patterns which are arranged before and after the bit pattern and each of which has a urn length that is longer than the minimum run length. The sync signal includes a specific code which indicates a position in the sector and which enables the DC control to be performed.

Digital data transmitting method

A transmitting method of digital data whereby information data can be reproduced at a high precision. In order to retain digital data in sectors comprising a plurality of sync frames and sequentially transmit, the sync frame is comprised of the sync signal and the run length limited code which satisfies the limitations of the minimum run length and the maximum run length, and the sync signal includes the sync pattern constituted by a bit pattern of a run length that is longer than the maximum run length by only 3T and addition bit patterns which are arranged before and after the bit pattern and each of which has a run length that is longer than the minimum run length. The sync signal includes a specific code which indicates a position in the sector and which enables the DC control to be performed.

An optical magnetic disk recording/reproducing apparatus is capable of reproducing address data when recording data signals on a magneto-optical disk and when deleting data signals from a magneto-optical disk. The reproduction of address data is performed with a high degree of stability. The apparatus includes an optical head, photoelectric voltage converters, various adders, a differential device and several switches. A first switch switches between a first position in which an output of the first switch is connected to the output of the differential device and a second position in which the output of the first switch is connected to a reference voltage. A second switch includes a first position in which an output of the second switch is connected to the output of one of the adders and a second position in which an output of the second switch is connected to the output of the first switch. Several control signal generators control the switches. Thus, the first switch outputs a signal from a differential amplifier during data reproduction and outputs a reference voltage during data recording and erasing.

Magneto-optical disk recording and reproducing apparatus capable of

In a photoelectric conversion amplifier for converting a light signal into a voltage signal, a resistor and a capacitor connected in parallel are provided between a non-inverted input terminal of a differential amplifier and a reference voltage source terminal, and thereby an offset voltage of the differential amplifier is eliminated and a frequency characteristic is improved to have a wideband.

Optical disk recording/reproducing apparatus and a photoelectric

A tracking control apparatus of an optical signal recording/reproduction apparatus, records and reproduces a data signal by causing a light spot focused on an optical recording medium to trace data-recording tracks and then accesses the light spot to a desired track. The tracking control apparatus varies a tracking-servo target value in a direction of performing the track-jumping operation, and then, if the tracking error signal exceeds a predetermined position level, the tracking control apparatus repeatedly varies the polarity of the tracking error signal until the light spot eventually arrives at the target track subject to the track-jumping operation. By virtue of the structure mentioned above, the tracking control apparatus can stably perform the track-jumping operation even when external disturbances, such as vibration, occur in the servo system.

Tracking control for optical information recording and reproducing

An equalizer apparatus is applied to a DBF disk recording medium in which a sampling clock is reproduced from clock pits recorded on the disk recording medium. A fixed coefficient equalizer includes an analog to digital converter, a memory and a two-dimension equalizer. The fixed coefficient equalizer suppresses interference from adjacent tracks and reduces the error rate of the reproduced data caused by crosstalk even in the case of a narrow track pitch. Further, by adding to the equalizer a sign detector, a FIR low-pass filter and a coefficient control circuit to form a variable coefficient equalizer, interference fluctuation attributed to the linear recording density, recording power irregularity, light spot shape, tracking error, etc., can be automatically compensated to suppress the equalization error caused by such fluctuation. Further, using the variable coefficient equalizer, clocking timing errors and fluctuations can be automatically and efficiently compensated.

Data recording/reproducing apparatus with two-dimensional equalizer for

A signal recording/reproducing apparatus equipped with a recording head section for recording signals on a recording medium and a reproducing head section for reproducing the signals recorded on the recording medium. The recording head section is arranged to record the signal to form N recording sub-tracks on the recording medium and the reproducing head section has M reproducing sub-heads which trace the N recording sub-tracks to reproduce the recording signal. The pitch of the M sub-heads thereof is equal to a pitch of the recording sub-tracks and the number M of the sub-heads is greater than the number N of the recording sub-tracks. The reproducing head section is coupled to a reproduction signal detecting section which is turn eliminates the interference and the crosstalk between adjacent tracks from the reproduced signal due to the reproducing head section. This arrangement allows narrowing the track pitch to increase the recording capacity and extremely improving the transfer rate concurrently with the elimination of the interference between the adjacent codes and crosstalk between the adjacent tracks.

Signal recording/reproducing apparatus

A data demodulation apparatus applicable to a playback input signal from a digital recording apparatus, which executes A/D conversion of the input signal with a sampling period that is equal to the bit separation of that signal, and obtains phase data for reproducing the phase of the clock signal component of the input signal each time that a '1' state bit is detected in a sampling period. For each sampling period, or set of successive sampling periods, data values are derived which respectively represent a number of bit positions of the input signal within that period and the presence or absence of '1' state bits in the period, and these data values are converted to serial form to respectively constitute a reproduced clock signal and a detected data signal.

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Yawata, Japan

Akira Kurahashi