摘要:
The invention provides a technique to widely spread the frequency spectrum of switching noise generated by a switching action and to reduce the noise level at a particular frequency. A switching regulator (6A) includes a computing unit with computing function. First, in the computing unit, a pulse-width-modulation processing unit (PWM) (2a) performs pulse-width-modulation processing of receiving a feedback signal corresponding to the output of a detector 1 to determine an on-duty cycle of a pulse signal. Subsequently, for the signal and data obtained by the PWM (2a) to be subjected to further modulation processing for spectrum spreading, a branching processing is performed by making changing-over unit (2d) randomly select asynchronous-modulation processing unit (ASM) (2e) or pulse-position-modulation processing unit (PPM). When the PPM is selected, another branching processing is performed by making the changing-over unit (2d) select a first PPM (2f) or a second PPM (2g) depending on the on-duty cycle.
摘要:
A double rotation Y-cut crystal unit includes a crystal element, which is respectively rotated by an angle θ° and an angle φ° in a counterclockwise direction centering on an X axis and a Z axis of crystal axes (X, Y, Z), which principal surface is perpendicular to a Y″ axis of newly-generated rotated crystal axes (X′, Y″, Z′), and which is formed into a rectangular geometry longer in one direction, wherein when the X′ axis is rotated by an angle α° in the counterclockwise direction with the Y″ axis serving as a central axis in a plane of X′-Z′ of the rotated crystal axes serving as the principal surface, a direction of a long side of the crystal element corresponds to the rotated X′ axis direction, and wherein the angle α° is set to (30−φ)°±45°.
摘要:
An optical disk apparatus comprises an optical pickup for directing a light beam onto pits formed in an optical disk and for receiving reflected light from the optical disk, an optical pickup supporting member including two guide rods for guiding the optical pickup in a radial direction of the optical disk, two first mounting members for mounting ends of one guide rod, and two second mounting members for mounting ends of the other guide rod, a chassis for mounting the first and second mounting members, an optical pickup driving mechanism including gears and a motor to move the optical pickup in a radial direction of the optical disk, a turntable on which the optical disk is located, and an optical disk drive motor for rotating the turntable. Each of the first fixing members includes a base fixed to the chassis, a guide rod supporting member for fixedly supporting the guide rod, and a flexible member located between the base and the guide rod supporting member for causing the guide rod supporting member to be displaced in a vertical direction with respect to a surface of the optical disk. A natural frequency of a system consisting of the one guide rod, the first mounting member, and the chassis is set to be less than that of the optical pickup, and of the optical disk.
摘要:
The present invention comprises an arrangement with removable optical element having a predetermined focal distance in the light path between a light source and an objective lens, so as to insert said optical element into the light path between the light source and the objective lens for playing back or recording onto one type of thickness of disk plates, as well as to remove it therefrom for playing back or recording onto another type of thickness of disk plates. Alternatively, by retaining variably the distance between the light source and the collimator lens, the distance between the light source and the collimator lens along with the light path is variably changed according to the thickness of the disk plate being inserted. Then by determining the type of the disk inserted and accordingly selectably inserting/removing the optical element, only one objective lens may be used to conform to the disk plates having different thicknesses.
摘要:
An optical scanning device for subjecting a light spot to a focussing operation and for causing the light spot to perform a tracking operation to reproduce information stored in a video or audio disc is disclosed in which a coil controlling a focussing optical system for forming the light spot and another coil causing the light spot to track the above-mentioned information are both placed in a magnetic gap included in a magnetic circuit formed by a permanent magnet and a magnetic member, and the magnetic circuit is arranged in a direction perpendicular to the direction of the tracking operation.
摘要:
In the case where the focus control or the tracking control of a light beam is performed by using the wobbling method in an optical information reproducing apparatus, the envelope of the reproduced signal obtained from the light reflected from the recording medium in a non-modulated state is diode-detected and the detected output is used as a focus control signal while the envelope of the reproduced signal obtained from the recording medium in a modulated state is diode-detected so as to be used as a tracking control signal.
摘要:
The invention provides a technique to widely spread the frequency spectrum of switching noise generated by a switching action and to reduce the noise level at a particular frequency. A switching regulator (6A) includes a computing unit with computing function. First, in the computing unit, a pulse-width-modulation processing unit (PWM) (2a) performs pulse-width-modulation processing of receiving a feedback signal corresponding to the output of a detector 1 to determine an on-duty cycle of a pulse signal. Subsequently, for the signal and data obtained by the PWM (2a) to be subjected to further modulation processing for spectrum spreading, a branching processing is performed by making changing-over unit (2d) randomly select asynchronous-modulation processing unit (ASM) (2e) or pulse-position-modulation processing unit (PPM). When the PPM is selected, another branching processing is performed by making the changing-over unit (2d) select a first PPM (2f) or a second PPM (2g) depending on the on-duty cycle.
摘要:
Instinctive operation of editing parameters of waveform is provided. Tabs 38, 40 and 42 are displayed on a display screen 14 to show existence of parameter edit screen layers of different combinations of characters, waveforms and channels. If one of the tabs are selected the display is switched to show the corresponding parameter edit screen layer. Channel characters or waveforms are displayed on the tabs 38, 40 and 42 and are changed dynamically according to the setting so that a user can easily realize setting outlines of the respective channels at a glance.
摘要:
When recording/reproducing an optical disc having a recording layer of multi-layer structure, an unwanted optical beam reflected from a recording layer other than a target layer for recording/reproduction is incident on a photodetector to cause an unwanted disturbance component to leak to a detection signal, giving rise to a degradation in the quality of a tracking control signal. In an optical pickup apparatus, for suppression of the degradation, an optical element is mounted having a diffraction area for diffracting part of the optical beam and light receiving planes for sub-optical beams are provided each of which has a light shielding zone or dead zone of a predetermined width on its central sectioning line.
摘要:
A motor using Hall effect elements is disclosed, in which a disk-shaped multi-pole magnet which is circumferentially divided into a plurality of magnetic poles each magnetized in an opposite polarity to its adjacent magnetic poles is attached to a rotary shaft and a magnetic circuit is constituted by the multi-pole magnet and a yoke plate disposed to face the multi-pole magnet. A pair of Hall effect elements are disposed within a magnetic field of the multi-pole magnet to detect positions of the respective magnetic poles of the multi-pole magnet. Output voltages from the pair of Hall effect elements are supplied to a pair of drive coils, respectively, to generate driving magnetic fluxes therein. A pair of pole pieces are mounted on the yoke plate to face the pair of Hall effect elements, respectively. The pair of pole pieces are axially movable to allow adjustment of spacings between the respective pole pieces and respective Hall effect elements so that magnetic flux densities supplied to the pair of Hall effect elements can be adjusted.