Mitsubishi Electric

About: Mitsubishi Electric is a company organization based out in Ratingen, Germany. It is known for research contribution in the topics: Signal & Voltage. The organization has 23024 authors who have published 27591 publications receiving 255671 citations. The organization is also known as: Mitsubishi Electric Corporation & Mitsubishi Denki K.K..

Numerical modeling of intensity and phase noise in semiconductor lasers

Abstract: A self-consistent numerical approach is demonstrated to analyze intensity and phase noise in semiconductor lasers. The approach takes into account the intrinsic fluctuations of the photon number, carrier number, and phase. A new systematic technique is proposed to generate the Langevin noise sources that derive the laser rate equations keeping their cross-correlations satisfied. The simulation is applied to AlGaAs lasers operating in a single mode. The time-varying profiles of the fluctuating photon and carrier numbers and the instantaneous shift of the oscillating frequency are presented. Statistical analysis of the intensity and phase fluctuations is given. The frequency spectra of intensity and phase noise are calculated with help of the fast Fourier transform. The importance of taking into account the carrier number noise source and its cross-correlation with the noise source on the phase is examined by comparing our results with those by conventional methods.

Collision avoidance system for voxel-based object representation

Abstract: Voxel-based objects are manipulated and interacted with in a physically ristic way such that during movement of the graphical objects, collisions are automatically detected and the graphical objects are prevented from penetrating each other. Applications include computer graphics and animation, CAD/CAM, and virtual reality applications that require real-time interaction between complex three-dimensional object models. When objects are represented in a voxel-based format where objects consist of clusters of regularly or irregularly spaced sampled data points, rather than a conventional graphic format where objects are represented by lists of polygons, primitive surfaces, or geometries, moving objects in virtual space involves shifting the voxel-based data in a large memory array representing the virtual space of the system and detecting collisions among moving objects by checking the new memory locations of object voxels to see if they are already occupied.

Speech recognition apparatus

Abstract: There are included a speech recognition unit (3) that speech-recognizes an input speech; a speech recognition dictionary (4) in which the words of the speech-recognized input speech are registered; a response speech data storage unit (6) that stores recorded speech data of the words registered in the speech recognition dictionary (4); an interaction control unit (7) that, when the speech recognition unit (3) speech-recognizes words registered in the speech recognition dictionary (4), acquires, from the response speech data storage unit (6), the recorded speech data corresponding to those words; a reproduction noise reduction unit (8) that performs a process to reduce the noises included in the recorded speech data acquired by the interaction control unit (7) from the response speech data storage unit (6); an amplitude adjustment unit (9) that adjusts the amplitude of the recorded speech data, in which the noises have been reduced by the reproduction noise reduction unit (8), to a predetermined speech level of amplitude; and a speech reproduction unit (10) that reproduces the recorded speech data outputted, for reproduction, by the amplitude adjustment unit (9)

Application of functionally graded material for solid insulator in gaseous insulation system

Abstract: Functionally graded materials (FGM) have spatial distribution of a material property in order to achieve efficient stress control. An application of the FGM to a solid insulator (spacer) for a gaseous insulation system, like gas insulated switchgear, is expected to improve electric field (E-field) distribution around the spacer. In this paper, we describe the applicability of the FGM spacer to gas insulated power equipment. In the FGM spacer, we gave spatial distribution of dielectric permittivity to control the E-field distribution inside and outside the spacer. This paper includes following key results for the applications of the FGM. Firstly, E-field simulation results when applying the FGM by a finite element method are presented, in which we show the effective reduction of the maximum field strength by applying the FGM. Next, a fabrication technique of the FGM spacer sample with not only step-by-step but also continuous changes of permittivity is presented by use of centrifugal force. Finally, dielectric breakdown tests using FGM samples which are accurately controlled the spatial distribution of permittivity are carried out under lightning impulse voltage applications. The test result indicates the increase of breakdown voltage (BDV). From these results, we verified the applicability and the fabrication technique of FGM spacer for improvement of the dielectric strength in the gaseous insulation system.