NEC

About: NEC is a company organization based out in Tokyo, Japan. It is known for research contribution in the topics: Signal & Layer (electronics). The organization has 33269 authors who have published 57670 publications receiving 835952 citations. The organization is also known as: NEC Corporation & NEC Electronics Corporation.

Bandwidth allocation system of virtual path in communication network of asynchronous transfer mode

Abstract: A node in an asynchronous transfer mode exchange network comprises a bandwidth monitor circuit for calculating a bandwidth used for a virtual path by measuring a cell amount entered into each virtual path, cell stored buffers for respectively storing an input cell for every virtual path, a bandwidth allocation control circuit for deciding a bandwidth allocation ratio, in accordance with a used bandwidth ratio obtained by reference to each bandwidth used for every virtual path from the bandwidth monitor circuit, depending on a change of the Queue length in a cell within the cell stored buffer, and an output bandwidth control circuit for controlling output of the respective cell stored buffers, in accordance with the bandwidth allocation ratio decided by the bandwidth allocation control circuit.

Audio decoding device, decoding method, and program

Abstract: An audio decoding device includes an energy correction unit (105) for correcting a target energy of a higher band component and a correction coefficient calculation unit (106) for calculating an energy correction coefficient from a low sub-band signal. These processing units execute the correction processing of the target energy required when performing the band extension processing using only real numbers. Thus, instead of a complex sub-band synthesis filter and a complex band extension unit, it is possible to use a real number sub-band synthesis filter and a band extension unit requiring less calculation amount while maintaining a high sound quality. Thus, it is possible to reduce the necessary calculation amount and the device size.

Image processing system for recording or reproducing an image signal sequence which has been encoded by employing two predictive coding methods and combining the results of those methods

Abstract: In an image recording system for use in recording a sequence of coded signals on a recording medium, such as a CD-ROM in response to a sequence of image signals divisible into a succession of frames each of which is subdivided into a plurality of splits, the image signals are selectively subjected to interframe coding and intraframe coding in a coder to be coded into first and second error signals, respectively, under control of a coding control circuit. The intraframe coding may be carried out about a selected split at every frame, at every preselected period, or at predetermined positions of each scene. The second and the first error signals are rearranged into the coded signals by delaying the second error signal relative to the first error signal. Such a second error signal serves to reproduce an initial image on reproducing the coded signals and enables a reverse reproduction, a quick search, a high speed reproduction, and the like in a reproducing system.

Pulse-time-modulated electron cyclotron resonance plasma discharge for highly selective, highly anisotropic, and charge-free etching

Abstract: Highly selective, highly anisotropic, notch‐free, and charge‐buildup damage‐free silicon etching is performed using electron cyclotron resonance (ECR) Cl2 plasma modulated at a pulse timing of a few tens of microseconds. A large quantity of negative ions are produced in the afterglow of the pulse‐time‐modulated plasma. The decay times of electron density, electron temperature, and sheath potential are considerably reduced. This is attributable to negative‐ion generation. Furthermore, the pulse‐time‐modulated plasma reduces the time averaged sheath potential. As a result of these effects, charged particles in the sheath are drastically modified from the continuous discharge, and they should improve the selective etching in the pulsed ECR plasma and eliminate charge accumulation on the substrate. Additionally, negative‐ion generation dramatically improves the plasma potential distributions in the nonuniform ECR plasma. This technique is also suitable for large scaled etching processes.

Microcellular mobile communication system

Abstract: A microcellular mobile radio communication system has a central base station and a plurality of radio base stations interconnected by a shared optical fiber transmission line. In the central and radio base stations, electrical radio signals are frequency-converted to frequencies assigned to the radio base stations and then converted into optical signals. In the central base station, the optical signals are combined for transmission through the optical fiber transmission line to the radio base stations. Alternatively, the frequency-converted electrical radio signals may first be combined and then converted into an optical signal for transmission. In the radio base stations, the electrical radio signals are converted to optical signals, which are combined and transmitted through the transmission line to the central radio station. In each radio base station, the frequency of the radio signal extracted from the received combined signal is frequency-converted to a frequency to be transmitted from its antenna, with the other signals filtered out. The central base station demodulates the received combined signal from the radio base stations into signals for the exchange office. The radio signals in different frequency bands assigned to each radio base station can simultaneously be transmitted through the shared optical fiber transmission lines between the radio and central base stations.