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.

A generalized proportionate variable step-size algorithm for fast changing acoustic environments

Abstract: This paper proposes a generalized proportionate variable step-size algorithm based on affine projection. It controls the step size for each tap individually based on the gradient approximated by the difference between the current coefficient and an averaged filter coefficient with delay. This step-size control is specifically effective for tracking fast changing acoustic environments. It is shown that the P-NLMS family and the ES algorithm are special cases of the proposed algorithm in terms of step-size control. Simulation results in the context of echo cancellation in artificial and real environments demonstrate that this step-size control combined with the affine projection algorithm (APA) reduces the echo by up to 5 dB compared to the standard APA. The best tracking performance, without a priori knowledge on the acoustic environment, among the same family of algorithms is obtained.

Charge pump-type booster circuit

Abstract: A charge pump-type booster circuit can reduce numbers of switches and capacitors. The charge pump-type booster circuit has a first electronic switch and a second switch connecting a high potential terminal and a low potential terminal of a charge capacitor are connected to a not grounded terminal of a first output capacitor connected to the ground at one side. These electronic switches are not conducted simultaneously. A third electronic switch is provided for connecting the high potential terminal of the charge capacitor and a not grounded terminal of a second output capacitor grounded at one side.

Method of mounting a semiconductor device to a substrate and a mounted structure

Abstract: A semiconductor device comprises a plurality of bump electrodes at least to one surface. A circuit substrate is formed with a laminate structure having an inner layer circuit and a mounting pad is formed on the substrate. The mounting pad has a concave portion and the bottom of the concave portion is in contact with the inner layer circuit. Further, an sealing resin is provided on the substrate. The bump electrode and the concave portion of the mounting pad are opposed, and the bump electrode is pressed to the bottom of the concave portion of the mounting pad, thereby deforming the pointed shape portion at the top end of the bump electrode. By the deformation the pointed shape portion, the contact portion between the bump electrode and the mounting pad is gradually enlarged from a point to a plane. After deforming the bump electrode by a predetermined amount, the sealing resin is hardened and the semiconductor device is mounted on a substrate.

Routing method and system using an internet protocol

Abstract: Routing methods, using an Internet protocol, which allows free alteration of the connection of a terminal between subnetworks such as local area networks (LANs) without necessitating modification of IP (Internet Protocol) addresses. The subnetworks are unified to constitute a network by a plurality of routers and each router is provided with a table which stores information according to every router indicating terminal addresses and times of connection to the network for every terminal included within the network. When a terminal is connected to any one of the subnetworks, the router corresponding to that subnetwork both updates the content of the table incorporated in that router and communicates to other routers the address and connection time of the connected terminal by means of a subscriber signal. A router which receives the subscriber signal updates the table incorporated in that router based on the results of comparing the connection time within the subscriber signal with the connection time within its own table.

Multi-function portable data-processing device

Abstract: A cellular phone of folded type has a cover panel (10a) and a base panel (10b) coupled by a hinge (11) for swiveling of the cover panel (10a) between a folded state and a developed state. The base panel (10b) mounts thereon a touch-sensitive panel (18) whereas the cover panel (10a) mounts an image projector (14) for projecting an image (20) of keyboard information onto the touch-sensitive panel (18). The keyboard information includes a label for each of the keypads for designating the function of the keypad, and switched based on the input mode of the cellular phone.