Abstract: An electronic component mounting structure is an electronic component mounting structure in which an electronic component group is mounted on a substrate, and a pattern constituting a part of a current path between the inflow port and the outflow port, the electronic component group includes a plurality of electronic components connected between the inflow port and the outflow port, each of the electronic components has a current inflow terminal electrically connected to the inflow port and a current outflow terminal electrically connected to the outflow port, and one of a first spatial distance group and a second spatial distance group has equal spatial distances within the one spatial distance group, and the first spatial distance group includes spatial distances between the inflow port and the inflow terminals, and the second spatial distance group includes spatial distances between the outflow port and the outflow terminals.

Abstract: An electronic component mounting structure is an electronic component mounting structure in which an electronic component group is mounted on a substrate, and a pattern constituting a part of a current path between the inflow port and the outflow port, the electronic component group includes a plurality of electronic components connected between the inflow port and the outflow port, each of the electronic components has a current inflow terminal electrically connected to the inflow port and a current outflow terminal electrically connected to the outflow port, and one of a first spatial distance group and a second spatial distance group has equal spatial distances within the one spatial distance group, and the first spatial distance group includes spatial distances between the inflow port and the inflow terminals, and the second spatial distance group includes spatial distances between the outflow port and the outflow terminals.

Abstract: According to one embodiment, a voltage measuring device that measures an input voltage signal includes a divider, a filter, an adder, and an analog-to-digital converter. The divider divides the input voltage signal into a first signal and a second signal. The filter filters the first signal and attenuates a direct current component of the first signal less than a predetermined frequency component of an alternating current component of the first signal. The adder adds an output signal of the filter to the second signal. The analog-to-digital converter converts an output signal of the adder into a digital signal. The divider adjusts the amplitude of at least one of the first signal and the second signal such that the level of a direct current component of the output signal of the adder is in the input range of the analog-to-digital converter.

Abstract: A magnetic disk drive includes a switching regulator configured to generate an output voltage, and a magnetic disk control unit that receives the output voltage as a power supply and performs data write and read operations on a magnetic recording medium. The switching regulator includes a voltage conversion part configured to generate a second voltage by switching a first voltage, a smoothing part configured to smooth the second voltage to thus produce an output voltage, a control part configured to control the switching on the basis of a difference between the output voltage and a reference voltage to thus stabilize the output voltage, and a reference voltage changing part configured to change the reference voltage in accordance with an operation mode of the magnetic disk control unit.

Abstract: The present invention provides an information storage apparatus that generates a tracking error signal based on a detection signal, and performs various control operations based on the tracking error signal. When the operation mode is a seek operation mode, the information storage apparatus generates a tracking error signal by holding the peak value of the detection signal. When the operation mode is a tracking operation mode, the information storage apparatus generates a tracking error signal directly from the detection signal. With this information storage apparatus, stable control operations can be performed, regardless of changes of conditions.

Abstract: The present invention provides an information storage apparatus that generates a tracking error signal based on a detection signal, and performs various control operations based on the tracking error signal. When the operation mode is a seek operation mode, the information storage apparatus generates a tracking error signal by holding the peak value of the detection signal. When the operation mode is a tracking operation mode, the information storage apparatus generates a tracking error signal directly from the detection signal. With this information storage apparatus, stable control operations can be performed, regardless of changes of conditions.

Abstract: The present invention provides an information storage apparatus that generates a tracking error signal based on a detection signal, and performs various control operations based on the tracking error signal. When the operation mode is a seek operation mode, the information storage apparatus generates a tracking error signal by holding the peak value of the detection signal. When the operation mode is a tracking operation mode, the information storage apparatus generates a tracking error signal directly from the detection signal. With this information storage apparatus, stable control operations can be performed, regardless of changes of conditions.

Abstract: The present invention provides an information storage apparatus that generates a tracking error signal based on a detection signal, and performs various control operations based on the tracking error signal. When the operation mode is a seek operation mode, the information storage apparatus generates a tracking error signal by holding the peak value of the detection signal. When the operation mode is a tracking operation mode, the information storage apparatus generates a tracking error signal directly from the detection signal. With this information storage apparatus, stable control operations can be performed, regardless of changes of conditions.

Abstract: An optical disk apparatus adapted to a mark edge recording method having a structure such that a data pattern experimentally recorded on an optical disk with one write power is reproduced plural times while changing reproducing conditions (for example, a slice level for binary-coding a reproduced analog signal) and the number of errors is calculated whenever the reproducing process is performed. The thus-structured process is repeated for using a plurality of write powers. An appropriate write power for the optical disk is determined in accordance with the obtained results of the calculations of the number of errors. In a case of a read-only optical disk, a data pattern experimentally and previously recorded on the optical disk is reproduced plural times by changing the reproducing conditions (for example, a slice level for binary-coding a reproduced analog signal), and the number of errors is calculated whenever the reproducing process is performed.

Abstract: A magneto-optical recording medium adapted for reproduction of a high resolution signal without the necessity of a reproducing magnetic field. The magneto-optical recording medium comprises a transparent substrate and deposits of a reproducing layer, a switch layer and a recording layer formed on the transparent substrate successively. The reproducing layer is a perpendicular magnetization film at a room temperature but is turned to an in-plane magnetization film when heated beyond a predetermined temperature. Each of the switch layer and the recording layer is a perpendicular magnetization film. The respective Curie temperatures Tc1, Tc2 and Tc3 of the reproducing layer, the switch layer and the recording layer satisfy the relationship of Tc1>Tc3>Tc2.

Abstract: An optical disk apparatus adapted to a mark edge recording method having a structure such that a data pattern experimentally recorded on an optical disk with one write power is reproduced plural times while changing reproducing conditions (for example, a slice level for binary-coding a reproduced analog signal) and the number of errors is calculated whenever the reproducing process is performed. The thus-structured process is repeated for using a plurality of write powers. An appropriate write power for the optical disk is determined in accordance with the obtained results of the calculations of the number of errors. In a case of a read-only optical disk, a data pattern experimentally and previously recorded on the optical disk is reproduced plural times by changing the reproducing conditions (for example, a slice level for binary-coding a reproduced analog signal), and the number of errors is calculated whenever the reproducing process is performed.

Abstract: A magneto-optic disk recording system capable of canceling shifts of the front edge and the rear edge of the record mark due to accumulation of heat. The recording system includes a magneto-optic disk having a record magnetic film, and a magnet for applying a bias magnetic field to the disk in the direction perpendicular thereto. The recording system further includes a laser diode for generating laser beams, an optical head for focusing the laser beam on the disk, a pulse generator for generating square wave pulses with a predetermined period, and a duty ratio controller for alternately increasing and decreasing the duty ratio of the square wave pulses every time data "1" of binary record data is generated. The laser diode is driven by a constant-current circuit for write power. There is connected a switch between the laser diode and the constant-current circuit for write power.

Abstract: A magnetooptic recording medium having a writing layer and a readout layer on a substrate is used. Data is recorded in the writing layer of the magnetooptic recording medium at a recording density smaller than a diameter of a focal spot of a laser beam. The data recorded in the writing layer of the magnetooptic recording medium at the recording density smaller than the beam diameter is reproduced by setting a reproducing laser power to a proper value. A reproduction laser power calibrating module executes the reproducing operation for calibration of the magnetooptic recording medium, thereby deciding the optimum value of the laser power which is used upon reproduction.

Abstract: An optical disk apparatus adapted to a mark edge recording method having a structure such that a data pattern experimentally recorded on an optical disk with one write power is reproduced plural times while changing reproducing conditions (for example, a slice level for binary-coding a reproduced analog signal) and the number of errors is calculated whenever the reproducing process is performed. The thus-structured process is repeated for using a plurality of write powers. An appropriate write power for the optical disk is determined in accordance with the obtained results of the calculations of the number of errors. In a case of a read-only optical disk, a data pattern experimentally and previously recorded on the optical disk is reproduced plural times by changing the reproducing conditions (for example, a slice level for binary-coding a reproduced analog signal), and the number of errors is calculated whenever the reproducing process is performed.

Abstract: An AC amplifying circuit is AC coupled through capacitors to a current/voltage converting circuit for converting a photosensitive current of a reproduction light from an optical disk medium to a voltage signal and for outputting as differential signals. A transient absorbing circuit compares reproduction voltages of the differential signals outputted from the AC amplifying circuit and controls charge and discharge of the capacitors on the basis of comparison outputs so that both of the reproduction voltages coincide with an AC ground, thereby automatically absorbing a transient state.

Abstract: Disclosed is a magneto-optical recording medium adapted for reproduction of a high resolution signal without the necessity of a reproducing magnetic field, whereby the magneto-optical recording medium comprises a transparent substrate, a reproducing layer, a switch layer and a recording layer formed on the transparent substrate successively. The reproducing layer is a perpendicular magnetization film at a room temperature but is turned to an in-plane magnetization film when heated beyond a predetermined temperature. Each of the switch layer and the recording layer is a perpendicular magnetization film. The respective Curie temperatures Tc1, Tc2 and Tc3 of the reproducing layer, the switch layer and the recording layer satisfy the relationship of Tc1>Tc3>Tc2.

Abstract: Disclosed is an optical disk apparatus having a zero-cross signal generating unit for differentiating a reproduced signal read from an optical disk and outputting a zero-cross signal when the differentiated signal crosses the zero level, and a gate signal generating unit for generating a gate signal using the reproduced signal, wherein a data pulse is outputted when the zero-cross signal is generated while the gate signal is being produced. A clamping circuit clamps the peak of a reproduced signal from an optical disk, an amplitude comparator compares the amplitude of a clamped signal, which is outputted by the clamping circuit, with a reference voltage, and an AGC control unit controls the gain of a variable-gain amplifier by generating a control voltage signal in dependence upon an amplitude difference. The gate signal generating unit generates the gate signal upon comparing the clamped signal outputted by the clamping circuit with a prescribed signal level.

Abstract: A magneto-optic recording method and a magneto-optic recording apparatus in which a magneto-optic overwritable medium having two layers, which layers have different coercive force--temperature characteristics and are coupled by exchange interaction, is heated by applying a light beam while an external magnetic field is being applied to the medium and in which data coded to invariably have FALSE states between two TRUE states is turned into a light beam having dual power levels and recorded on the medium, the magneto-optic recording method including the steps of: forming record marks by heating the magneto-optic overwritable medium to a high temperature by means of a high light beam power associated with a FALSE state in the write data; and of heating the magneto-optic overwritable medium to a low temperature by means of a low light beam power associated with a TRUE state in the write data.

Abstract: A magneto-optic overwrite disk recording system capable of canceling shifts of the front edge and the rear edge of the record mark due to accumulation of heat. The recording system includes a magneto-optic overwrite disk having a memory magnetic film and a record magnetic film, a first magnet for applying an initialization magnetic field with a first strength vertically to the disk, and a second magnet for applying a bias magnetic field with a second strength smaller than the first magnetic field to the disk in the direction opposite to the initialization magnetic field. The recording system further includes a laser diode for generating laser beams, an optical head for focusing the laser beam on the disk, a pulse generator for generating square wave pulses with a predetermined period, and a duty ratio controller for alternately increasing and decreasing the duty ratio of the square wave pulses every time data "1" of binary record data is generated.

Abstract: An apparatus for reading out data recorded on a magneto-optic disk by detecting edges of magnetic domains formed such that the direction of magnetization thereof is opposite to the direction of the magnetization initially formed on the magneto-optic disk, the edges of the magnetic domains corresponding to "1"s of the recorded data. The data read out apparatus includes a read out signal generation portion for generating a read out signal by scanning the magnetic domains on the magneto-optic disk, a binarization portion for converting the read out signal into a binarized signal, and an edge detection portion for detecting from the binarized signal a front edge signal and a rear edge signal corresponding to the front edge and the rear edge of the magnetic domains, respectively. A front edge signal from a fixed delay device and a rear edge signal from a variable delay device are input to an OR circuit and an edge signal is output therefrom.