Hitachi, Ltd.

Nec Corporation

Hitoshi Yokota

Tsutomu Hara

Kenichi Yoshida

Takashi Suga

Takashi Maruyama

Makoto Torigoe

Hideki Osaka

Satoshi Nakamura

Hiroshi Ito

Hironori Oikawa

Kenji Kashiwagi

Hideo Sawada

Kazuma Kishi

Mikihiro Tanaka

Hiroyuki Inokuchi

Hiromu Ishihara

Mariko Kasai

Junichi Fujikata

Hiroki Funato

Takashi Matsumoto

Tsutomu Ishi

Kouichi Uesaka

Keisuke Fukumasu

Yoshiyuki Tsuchie

Tatsuhiko Matsuoka

Nobuhiro Kato

Jun Saito

Tatsuji Noma

Giichirou Yokokura

Provided is a noise equivalent circuit for completing an EMC analysis in a practical time and through a low-cost calculation process at an upstream stage of system design. The noise equivalent circuit includes one or more energy sources; a propagation path for propagation of energy from the energy source including a conductive path such as a cable and an electromagnetic field coupling path due to the coupling of an electric field and a magnetic field with another electronic device or cable; and a GND port connected to a system, and each port is represented by the noise voltage source or the noise current source and the internal impedance. This noise equivalent circuit can determine an external impedance that is varied depending on a load connected externally or the distance from an external device or a cable, whereby the noise of the system as a whole can be analyzed.

Noise equivalent circuit

A system and method for automatically calculating an optimum layout of a wireless cell station in an environment using a wireless communication system, thereby achieving a timesaving and resources-saving cell design procedure. The system calculates an optimum layout of the wireless cell station based on information of terminal locations.

Apparatus and method for laying out wireless cell, and recording medium for programs achieving the same

A communication system is provided of selecting the most approximate line from two or more connectable lines and connecting with a provider through the selected line in the mobile communication environment. The mobile device and the public phone of each phone company provide a standard wireless data communication facility, respectively. The public line pre-stores information about dial-up numbers of access points and a transmission speed of an internet provider. When the user starts the communication, the mobile device operates to obtain the most approximate access point information from each of the public phones and then dial up the most approximate access point through the public phone/line well-specified to the user.

Communication system

A wireless LAN system is provided to make a frequency band setup task easy such that interference among base stations is reduced. The base station connected to a wired LAN includes a wired connection unit connected to the wired LAN and a wireless communication unit communicating with a LAN terminal via radio waves. The base station finds frequency bands already used by other devices in a place where the base station is installed and sets up a frequency band not used by the other devices as a frequency band to be used by the wireless communication unit to automatically set up a frequency band of radio waves to be used by the wireless communication unit.

Base station for wireless communication and method for setting up frequency band in the base station

A shield structure that transmits a radio wave in a specific frequency band and that exhibits a high shield characteristic in other bands. An opening portion having a specific shape and a specific perimeter length is formed on a conductor. A filter having a specific shape and a specific size is connected to the opening portion.

Frequency-selective shield structure and electric device having the structure

A optical device including conductive films having a first and second surfaces, one hole, surface specific shapes periodically, and a layer inserted as an intermediate layer between the first and the second surface of conductive films. The intermediate layer has the effect for improving surface roughness of the surface of conductive film. A light incident upon one surface enhances an intensity transmitted though the hole.

Optical head and optical device for enhancing the intensity of a transmitted light

A printed circuit board with reduced noise effects and without the need to increase the distance between a noise source and a wireless communication board. The circuit board includes multilayer structural conductive layers having a first conductive plane connected to power supply potential and a second conductive plane connected to ground potential. The first and second conductive planes are formed such that an electric field generated by a potential difference between the first conductive plane and the second conductive plane is concentrated on one side of one of the first conductive plane and the second conductive plane. The conductive plane associated with the concentrated electric field and the wireless communication board are on different sides relative to the conductive plane that is not associated with the concentrated electric field.

Printed circuit board and wireless communication apparatus

A semiconductor device includes a semiconductor die having patterned circuitry, a plurality of terminals coupled to the die, and an indication providing signal noise information of at least one of the terminals.

Semiconductor device and design support method of electronic device using the same

There is provided a technology for realizing an PCI expansion adapter for a PC card which is connectable to a desktop type personal computer PCI expansion connector using a low profile PCI. The PCI expansion adapter includes an expansion unit which is provided with an electrical connector to a PCI bus, a low profile PCI expansion board provided with a PC card control element and an electrical connector to the PC card, wherein the low profile PCI expansion board and the expansion unit are connected by the electrical connectors mounted on the respective boards.

PCI expansion adapter with PC card slot and electronic apparatus provided with the same

An electronic apparatus is comprised of a circuit apparatus; and an electromagnetic wave absorbing device arranged in the vicinity of the circuit apparatus in an insulating manner with respect to a circuit of the circuit apparatus, and having a metal loop, a portion of which is made of a high resistor. The metal loop contains a first member having a resistor having a resistance value smaller than, or equal to several ohms; and a second member having a resistor having a resistance value larger than, or equal to several ohms, and connected so as to form an electric loop in combination with the first member. The electromagnetic wave absorbing device containing a first member having a resistor having a resistance value smaller than, or equal to several ohms; and a second member having a resistor having a resistance value larger than, or equal to several ohms, and connected so as to form an electric loop in combination with the first member, is mounted on an adhesive tape and the like in order to be attached to an arbitrary electronic appliance. Also, this electromagnetic wave absorbing device is mounted on a circuit board, and an electronic component such as an IC and an LSI as a portion of this structure. As a result, this electromagnetic wave absorbing device realizes suppressions and reductions of electromagnetic noise such as EMI and higher harmonic waves thereof.

Electromagnetic noise reducing device, noise reducing electronic component and electronic appliance manufacturing method

In a circuit board having a multilayer structure comprising a ground pattern and a power-supply pattern both, for example, by forming a plurality of slits along each side of the ground pattern or the power-supply pattern, a long thin conduction path connecting a corner and a side center of the ground pattern is formed and resistive elements are placed in the middles of the conduction path to short, circuit the corner and a side center of the ground pattern. Therefore, portions corresponding to an antinode and a node or antinode and an antinode of a standing wave are short-circuited. The standing wave is generated when electric power is supplied to ICs and LSIs mounted on the circuit board. Thus, noise sources caused by the standing wave cancel each other. As a result, the occurrence of an antiresonance phenomenon and an increase in impedance of the power supplying system caused by the standing wave can be suppressed.

Reducing impedance of power supplying system in a circuit board by connecting two points in one of a power supply pattern and a ground pattern by a resistive member

The objective of the present invention is to provide an information processing device that is operable by a battery and which suppresses the generation of standing waves and has little radiation noise. In the information processing device of the present invention having means for connecting to a battery pack that stores a battery for supplying power to the information processing device, there is one or more capacitive element (for example, a capacitor) in the proximity of the terminals of the positive and negative poles of the battery when the battery pack is connected to the information processing device, and it is possible for at least the terminal of the positive pole of the battery or the terminal of the negative pole of the battery to be connected electrically to the ground of the information processing device by way of this capacitive element.

Growing community of inventors

Kawasaki, Japan

Hitoshi Yokota