Hitachi, Ltd.

Hitachi Consumer Electronics Co., Ltd.

Hitachi Media Electronics Co., Ltd.

Koichi Hirose

Akira Shibata

Akio Fukushima

Masakazu Ikeda

Akihiro Yamamoto

Koichiro Nishimura

Kazuo Kondo

Yoshinori Okada

Isao Nakagawa

Iwao Aizawa

Kuniaki Miura

Fumio Isshiki

Mitsuru Kudo

Noboru Kojima

Teizo Tamura

Keiichi Komatsu

Shigeru Okada

Makoto Konosu

Masaharu Aridome

In a recording medium, an extension address is obtained without changing the number of bits of the address embedded in the wobble. The wobble address is partially or wholly encoded to embed the address information. At the time of reproducing the address information, the original address information is obtained by restoring the embedded information by the decoding process.

Information recording medium, address generation and detection method, and reproducing and recording apparatuses

Optical recording medium capable of increasing the number of wobble address bits and method for recording and reproducing thereof

Recording capacity per layer is detected from a disc and bit allocation of wobble addresses in a conventional optical disc and bit allocation in a high-density optical disc are controlled selectively to detect physical position addresses on the disc. Address detection can be performed for two kinds of discs which are equal in structure of addresses embedded in wobbles but different in bit allocation of addresses.

Address generating and detecting method and reproducing and recording apparatus

An operation mode is arranged to be switched between in recording/reproducing and in adjustment. A switching circuit with a hold circuit therefor is on a light receiving element including an optical pickup having a laser light source emitting a laser beam, an objective lens focusing the laser beam onto a recording layer of a disc, and a light receiving element receiving an optical signal modulated. The light receiving element is operable in an adjustment mode for selecting of the signal of an individual light-receiving surface and for outputting the same. The light receiving element is configured so that the address selection signal line in the adjustment mode may be used also as a sensitivity switching signal line. A compact and highly reliable optical pickup with less signal lines can be provided.

Optical pickup and optical disk driving apparatus using the same

A magnetic recording and reproducing apparatus including a recording head, reproducing heads and reproducing pre-amplifiers each mounted on a rotating cylinder for allowing recording and reproducing operations at the same time, in which two signal channels are defined by first and second double azimuth heads each made up of two reproducing heads and first and second integrated circuits are arranged on the rotating cylinder in close proximity to the first and second double azimuth heads, respectively. Each of the integrated circuits includes two pre-amplifiers corresponding to two reproducing heads of the first or second double azimuth head and selectively outputs one of two amplified reproduced signals from the above pre-amplifiers which is higher in signal level, and a head discrimination signal is added to the output signal. The input part of each reproducing pre-amplifier is constructed to perform a differential operation, and one of the output signals of the first and second integrated circuits is selectively sent to a fixed side through a single transmission means in accordance with a control signal supplied from the outside. The magnetic recording and reproducing apparatus having the above construction can be made small in jitter and crosstalk, and can reduce the number of elements for transmitting signals between the rotating cylinder and the fixed side.

Magnetic recording and reproducing apparatus

A high-density analog integrated circuit having built-in resistor elements formed simultaneously with the formation of the base of transistor is disclosed in which a high-resistance element is formed of an ion-implanted resistor, a low-resistance element is formed of a base-diffused resistor, and a pair of high-resistance elements are connected in such a manner that a difference between a signal current flowing through one of the high-resistance elements and another signal current flowing through the other high-resistance element is outputted, and in which an ion-implanted resistor having a high resistance and a thin film capacitor having a small capacitance make up a built-in time constant circuit, which makes it possible to integrate on one semiconductor chip circuits such as a filter circuit for video signal and an input bias circuit.

Analog integrated circuit

An output section of an electronic circuitry having differentially connected transistors is connected to the emitter of a first transistor having an inverted conductivity type relative to that of differentially connected transistors and to the collector of a second transistor in combination with the first transistor to constitute an inverted Darlington amplifier. The output current is derived from the emitter of the second transistor, so that the electronic circuitry can be operated under the application of a low supply voltage and suited for an integration circuit.

Electronic circuitry utilizing an inerted Darlington amplifier output

A magnetic tape reproducing apparatus includes a plurality of playback heads, a plurality of damping circuits for damping output signals from the associated playback heads, a switching circuit for sequentially passing the output signals from the plurality of damping circuits, a reproduction equalizer for creating substantially a total reproduction equalizing characteristic for the output signal from the switching circuit which signal is subjected to a peaking characteristic, and a signal processor for converting the output signal of the reproduction equalizer to a recorded information signal. Each damping circuit serves to damp the output from the associated playback head so that the peaking characteristic created by its equivalent resonant capacitance, its equivalent damping resistance, the inductance of the associated playback head and the capacitance thereof does not govern the total equalizing characteristic.

Magnetic tape reproducing apparatus

A picture reproducing apparatus for a helical scanning video tape recorder including an impedance transformer; a video head connected to the input of the impedance transformer; a resonance circuit connected to the output of the impedance transformer; a pre-amplifier connected to the output of the resonance circuit; a feedback resistor connected between the junction of the pre-amplifier and resonance circuit and the output of the pre-amplifier; and an output terminal connected to the output of the pre-amplifier. The impedance transformer has the output impedance four times as high as the input impedance thereof.

Picture reproducing apparatus in a helical scanning video tape recorder

A non-linear emphasis circuit comprising a high-pass filter receiving an input signal, a compressor processing the output of the filter with such a variable gain as to decrease or increase responsive to an increase or a decrease of the output of the filter and an adder for adding the input signal and the output of the compressor at a predetermined rate for producing a non-linearly emphasized signal. The circuit has a structure adapted for production in an IC form and easy to design.

Non-linear emphasis circuit

A plurality of signals picked up by a plurality of video heads are amplified by a plurality of amplifiers and then are fed to a plurality of switch circuits where the signals are alternately switched. The signals from the switch circuits are coupled by a coupling line into a continuous signal which in turn is fed to an automatic gain control circuit. The automatic gain control circuit provides at its output an FM output signal with a constant level. A color signal is taken from a portion between the coupling line and the automatic gain control circuit.

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Yokohama, Japan

Koichi Hirose