Abstract: According to one embodiment, a plurality of light receiving elements photoelectrically convert light signals having information signals, respectively. A plurality of first amplification circuits amplify currents of electric signals from the respective light receiving elements. A selecting section selectively outputs one of signals amplified by the plurality of first amplification circuits. A second amplification circuit amplifies a voltage of the signal output from the selecting section, and supplies the signal to the outside.

Abstract: First and second photo detector cells are independently provided. At the time of a disk reproducing laser power, an addition output of electric signals subjected to opto-electric conversion from the first and second photo detector cells is derived as a control signal of a laser drive circuit by a first processing circuit. At a disk recording laser power, on the other hand, an electric signal subjected to opto-electric conversion from any one of the first and second photo detector cells is derived as a control signal of the laser drive circuit by a second processing circuit.

Abstract: A light receiving element circuit is an integrated circuit configured by a light receiving element which photoelectrically converts an optical signal having an information signal, and amplifier circuits which amplify the photoelectrically converted electric signal and output the signal. The light receiving element circuit comprises a reference voltage generating circuit which generates a reference voltage of the amplifier circuits, a reference voltage output terminal which outputs the reference voltage, a reference voltage input terminal which inputs a reference voltage from the outside, a switch which switches the reference voltage from the reference voltage generating circuit and the reference voltage inputted from the reference voltage input terminal, and a reference voltage switch terminal which inputs signal for controlling the switch.

Abstract: According to one embodiment, a plurality of light receiving elements photoelectrically convert light signals having information signals, respectively. A plurality of first amplification circuits amplify currents of electric signals from the respective light receiving elements. A selecting section selectively outputs one of signals amplified by the plurality of first amplification circuits. A second amplification circuit amplifies a voltage of the signal output from the selecting section, and supplies the signal to the outside.

Abstract: An optical disk device includes first pickup portion PU1 which outputs first detection signal by irradiating first laser beam having first wavelength to surface of optical disk and receiving its reflected light, second pickup portion PU2 having independent structure, which irradiates second laser beam having second wavelength and receives its reflected light so as to output second detection signal, and control portion in which with the first laser beam and the second laser beam so as to receive the first detection signal and the second detection signal, when system data of first class disk system area is detected from the first detection signal, the optical disk is determined to be the first class disk and when system data of second class disk system area is detected from the second detection signal, that optical disk is determined to be the second class.

Abstract: An optical disk apparatus of the invention includes an optical pickup which irradiates an optical disk with a laser beam, a light-reception unit including a first light-reception element and a second light-reception element, the light-reception unit receiving the laser beam reflected from the optical disk to provide a first photodetection signal and a second photodetection signal corresponding to the reflected laser beam, measuring units and which receive the first and second photodetection signals from the optical pickup to measure propagation delay time difference between the first and second photodetection signals, a delay unit which delays the first and second photodetection signals based on the signal propagation delay time difference such that delay times of the first and second photodetection signals are equalized to each other, and a signal processing circuit which processes the first and second photodetection signals delayed by the delay unit, and provides the processed signals.

Abstract: A magnetic recording/reproduction apparatus comprises a magnetic tape running apparatus to rotate a rotary drum and run a magnetic tape with the magnetic tape being contact with, at least, part of the circumferential surface of the rotary drum, a plurality of erasing magnetic heads installed on the rotary drum so that the magnetic tape are in contact with the heads and used to erase recording signal, a plurality of recording magnetic heads used for recording, a plurality of erasing circuits installed on the rotary drum to output erasing signal to each of the erasing magnetic heads, a plurality of recording circuits connected to the recording magnetic heads respectively and installed on the rotary drum so that the recording circuits are selectively be gone to enable state and disable state, one or more rotary transformers connected to erasing circuits in common, and a driving circuit to record information signal in the magnetic tape through recording magnetic heads, recording circuits, and rotary transformers.

Abstract: A magnetic recording/reproduction apparatus comprises a magnetic tape running apparatus to rotate a rotary drum and run a magnetic tape with the magnetic tape being in contact with, at least, part of the circumferential surface of the rotary drum, a plurality of erasing magnetic heads installed on the rotary drum so that the magnetic tape are in contact with the heads and used to erase recording signal, a plurality of recording magnetic heads used for recording, a plurality of erasing circuits installed on the rotary drum to output erasing signal to each of the erasing magnetic heads, a plurality of recording circuits connected to the recording magnetic heads respectively and installed on the rotary drum so that the recording circuits are selectively be gone to active state and non-active state, one or more rotary transformers connected to erasing circuits in common, and a driving circuit to record information signal in the magnetic tape through recording magnetic heads, recording circuits, and rotary transfo

Abstract: A rotary scanning-type magnetic recording and reproduction apparatus comprises a plurality of magnetic heads installed on a rotary drum, and being in contact with a magnetic tape running on the peripheral surface of the rotary drum, for recording the information signal onto the magnetic tape and/or reproducing the information signal from the magnetic tape, a plurality of recording circuits connected to the magnetic heads respectively, for processing the information signal to be recorded on the magnetic tape transferred from outside the rotary drum and output it to the magnetic head, a rotary transformer for transferring the information signal sent from outside the rotary drum to the recording circuits, and a control circuit for sequentially selectively bringing the recording circuits into an active state according to the rotational position of the rotary drum, and bringing the recording circuits into an active state only during a period of time when the information signal is detected.

Abstract: A magnetic recording and reproduction apparatus includes a rotary drum to be driven to rotate, a first head provided on the rotary drum, a second head provided on the rotary drum so as to be set in an enable state when the first head is in a disable state, first and second amplifying circuits connected to the first and second heads, respectively, and capable of being set in an enable or disable state by a selection signal, a rotary transformer commonly coupled to the first and second amplifying circuits, and a selection signal generating portion for supplying a selection signal to the first and second amplifying circuits in synchronism with rotation of the rotary drum.

Abstract: An optical recording device for forming recording tracks of an indented pattern on a magnetic recording tape comprises a rotary drum which has at least two windows, the magnetic recording tape being driven obliquely on the windows along an outer surface of the drum, and an optical system, disposed inside the rotary drum, for converting a modulated laser beam incident on the optical system into two slit beams, major axes of sections of which form a predetermined angle and for emitting the slit beams on the magnetic recording tape through the windows, whereby the recording tracks of the indented pattern in correspondence with the signal are formed obliquely on the magnetic recording tape with respect to a longitudinal direction of the magnetic recording tape by the slit beams so as to form different azimuths between adjacent recording tracks.