Hitachi, Ltd.

Hitachi-Lg Data Storage, Inc.

Other

Hitachi-Lg Data Storage Co., Ltd.

Hirotoshi Fukuda

Masato Sano

Toshihiro Matsunaga

Kiyonobu Teramoto

Kazunaga Narita

Hirohito Ishibashi

Takeshi Ikeda

Junichi Iida

Kazuhiko Ono

Toshinori Arai

Proposed is a highly reliable information detecting apparatus and method. In an information detecting apparatus and method for detecting transmission information a transmission signal in which a burst period of transmitting a burst signal and a space period as a no-signal period are repeated in a pattern according to the subject matter of the transmission information, whether the absolute value of a signal amplitude level of the transmission signal is not less than a first threshold is detected, whether the absolute value of a signal amplitude level of the transmission signal is not less than a second threshold is detected, and whether the amplitude level displacement of the transmission signal is based on noise or the reception of the transmission information is determined based on the detection results.

Information detecting apparatus and method

A motor driving circuit includes at least one set of switching elements, each set of switching elements being two switching elements connected in series to each other, and a diode connected in parallel with one of the two switching elements connected on a power source side, a terminal of a motor to be driven being connected to a junction point between the two switching elements. A voltage transfer element is provided for transferring, from the junction point between the two switching elements, a voltage of a counter electromotive force generated at the motor, to an input end of the other of the two switching elements connected on a ground side.

Motor driving circuit

The invention relates to a disc discriminating method and an optical disc information reproducing apparatus wherein DVD-RAM which is DVD-RAM1 or DVD-RAM2 and DVDRW which is DVD-RW or DVD+RW which cannot be respectively determined based upon distance from the surface of a disc to the recording face, the number of recording faces and the reflectance can be discriminated. In case an optical disc is DVD-RAM or DVDRW, the amplitude of a push-pull tracking error signal is measured by a microcomputer in a state in which servo control is executed based upon a focus error signal. Determination is performed based upon the amplitude of the push-pull tracking error signal, when the amplitude of the push-pull tracking error signal is larger than a predetermined value, the optical disc is judged as DVD-RAM and when the amplitude is smaller than the predetermined value, the optical disc is judged as DVDRW.

Disc discriminating method and information reproducing apparatus using thereof

The invention relates to a disc discriminating method and an optical disc information reproducing apparatus wherein DVD-RAM which is DVD-RAM1 or DVD-RAM2 and DVDRW which is DVD&minus;RW or DVD&plus;RW which cannot be respectively determined based upon distance from the surface of a disc to the recording face, the number of recording faces and the reflectance can be discriminated. In case an optical disc is DVD-RAM or DVDRW, the amplitude of a push-pull tracking error signal is measured by a microcomputer in a state in which servo control is executed based upon a focus error signal. Determination is performed based upon the amplitude of the push-pull tracking error signal, when the amplitude of the push-pull tracking error signal is larger than a predetermined value, the optical disc is judged as DVD-RAM and when the amplitude is smaller than the predetermined value, the optical disc is judged as DVDRW.

When a deviated gravity disc is reproduced at a higher rate with the disc reproducing apparatus, an excessive vibration is generated and this vibration gives adverse effect on the disc reproducing apparatus and peripheral components/apparatuses, and/or may represent an annoyance to a user. A vibration information detector for detecting vibration of the disc reproducing apparatus or a deviated gravity information detector for detecting amount of gravity deviation of disc is provided, and as a result of such detection of an imbalance (i.e., excessive vibration or mass eccentricity), and a reproducing rate switching control controls sets and limits the reproducing rate of the disc reproducing apparatus to a substitute speed which is lower or higher than a normal reproducing speed.

Growing community of inventors

Chigasaki, Japan

Hirotoshi Fukuda