Fujitsu Corporation

Takeshi Takano

Yasuyuki Oishi

Toru Maniwa

Kazuo Nagatani

Tokuro Kubo

Takaharu Nakamura

Yuuta Nakaya

Takayoshi Ode

Nobuhisa Aoki

Eisuke Fukuda

Yukio Takeda

Manabu Kai

Kazuo Kawabata

Makoto Yoshida

Takashi Yamagajo

Takanori Iwamatsu

Alexander Nikolaevich Lozhkin

Hideto Furukawa

Hiroyuki Hayashi

Yu Yonezawa

Xiaoyu Mi

Takeaki Shimanouchi

Andrey S Andrenko

Takumi Miyashita

Kazuo Asakawa

Naoyuki Mishima

Takeshi Toda

Takashi Kimoto

Tamio Saito

Liang Zhou

Yoshiaki Kaneko

Eiji Itaya

Naoyuki Saito

Yukihiro Moriyama

Naoyuki Saitou

Koji Takata

Masaru Kabashima

Yuji Kaneko

Yoshiya Ohsaki

Akihiko Kimura

Yasunobu Watanabe

A communication device is used by a mobile station to perform wireless communication with another mobile station. The communication device includes a processor configured to set a transmission resource according to a present position of the mobile station, the transmission resource being set based on transmission resource association information including different transmission resources assigned to plural assignment areas provided at different positions along a road through which the mobile station passes; and a transmitter configured to transmit data with the use of the transmission resource that has been set.

Mobile station communication device, inter-mobile station communication system, and inter-mobile station communication method

An antenna device includes: a substrate; a radiating electrode formed on the substrate, a ground electrode formed on the substrate and disposed opposite the radiating electrode, a feed line as a distributed constant transmission line connected via a feed point to the radiating electrode, at least one impedance matching element for impedance-matching the radiating electrode at a prescribed signal frequency by being connected in parallel with the radiating electrode to the feed line at a position a prescribed distance away from the feed point, and a switch, interposed between the at least one impedance matching element and the feed line, for connecting or disconnecting the at least one impedance matching element to or from the feed line in accordance with a prescribed control signal.

Antenna device and communication device

A mobile communications terminal is disclosed that includes a determination part configured to determine whether to perform relay control based on a signal received from at least one of a radio base station, a stationary relay station, and another mobile communications terminal performing relay control and a control part configured to control the mobile communications terminal so that the mobile communications terminal performs an operation as a relay station in response to the determination part determining to perform the relay control.

Mobile communications terminal and communication control method

A Doherty amplifier is provided with a clipping circuit for making signal power flow to ground if the signal power becomes equal to or higher than a predetermine value in order to prevent a carrier amplifier, which is a small amplifier, from being destroyed if the signal power is increased to a sevenfold to tenfold multiple of a ratio of the size of the carrier amplifier to that of a peak amplifier.

Power amplifier

A DC/DC converter capable of controlling an output signal using a broadband signal input is provided. By employing the above DC/DC converter as a power supply, a highly efficient power amplifier can be configured. The above DC/DC converter includes two class-C amplifiers, a rectifier circuit connected between each output of the two class-C amplifiers, and an oscillator of a predetermined frequency signal. The predetermined frequency signal output from the oscillator is input to each of the two class-C amplifiers, and by controlling the phase difference of the predetermined frequency signal input to the two class-C amplifiers, the magnitude of a direct current voltage output from the rectifier circuit is made variable.

DC/DC converter, and power amplifier applying the same

A drive control method for a micro machine device is provided. The micro machine device is made up of first and second electrodes opposed to each other and a dielectric layer disposed between them. The drive control method includes the steps of applying a control voltage between the first and the second electrodes so that an electrostatic force is exerted on the first and the second electrodes for displacing the first or the second electrode, and switching polarity of the control voltage at a predetermined period or a shorter period.

Drive control method and unit for micro machine device

Of the antenna group composed of multiple ones of the transmission antennas and multiple ones of the reception antennas, the present method selects an antenna group which satisfies a first criterion relating to communication quality. Out of combinations of transmission antennas and reception antennas included in the selected antenna group, combinations which satisfy a second criterion relating to communication quality are selected. Using a part of or all of the selected combinations of transmission antennas and reception antennas, the above-mentioned communication is performed. As a result, selection of optimal transmission antennas and reception antennas according to radio communication environment can be performed with high speed with a smaller amount of operation amount than the previous art.

Radio communication method, transmitter, and receiver

A power amplifier negates a memory effect and is applied a linearizer using a digital predistortion system even in an inexpensive device. The power amplifier compares an input signal power against a sampled component of an output power, and provides predistortion to the input signal power so as to minimize a difference as a result of the comparison. The power amplifier comprises a gain lookup table storing a gain coefficient value corresponding to a temperature address determined for an input power; a phase lookup table storing a phase coefficient value corresponding to the temperature address determined for the input power; a transversal filter, which is input with the input power, and which outputs the temperature address; and a coefficient multiplier modulating the input signal using a gain coefficient value and a phase coefficient value, which correspond to the temperature address and which are read out from the gain coefficient lookup table and the phase lookup table.

Power amplifier with distortion compensation circuit

A transmitter includes a first limiter for performing a first clipping in which an amplitude part at a level higher than an amplitude level based on a first clipping level is cut out from an input signal to be subjected to power amplification, a second limiter for performing a second clipping in which an amplitude part at a level lower than the amplitude level based on a second clipping level is cut out from a first signal that has undergone the first clipping, a separation section for separating a second signal that has undergone the second clipping into an amplitude modulated part and a constant amplitude part, a first amplifier for amplifying the amplitude modulated part, a second amplifier for amplifying the constant amplitude part, and a combiner for outputting a third signal obtained by combining the amplitude part amplified by the first amplifier and the constant amplitude part amplified by the second amplifier.

Transmitter and power amplifying method

A control unit and a control method are disclosed. First and second changing units change impedances of two or more first and second components within predetermined first and second ranges, respectively, the first and the second components affecting an output signal. An evaluation function value calculating unit calculates an evaluation function value that is dependent on the impedances of the first and the second components. A gradient vector calculating unit calculates a gradient vector based on the difference between the evaluation function values before and after the impedance change of the second components. Based on the gradient vector, impedance of each of the first components is changed such that the evaluation function value takes a desired value.

Control unit and a control method

A disk tag reading device is a device for reading contents of an electronic tag attached to a disk. A holder which is inserted into a central hole of the disk configures an antenna for communicating with the electronic tag attached to the disk.

Disk tag reading device

Disclosed in a reading apparatus for supplying power to at least one of a plurality of superimposed RF tags and reading information from the tag while power is being supplied thereto. The apparatus includes means for generating high-frequency signals; electromagnetic wave generating means to which the high-frequency signals are input for generating electromagnetic waves from a plurality of locations, e.g., from both sides of the superimposed tags, by the high-frequency signals and causing the electromagnetic waves to interfere with each other on the tags; means for controlling the phase difference between the high-frequency signals, which are supplied to the electromagnetic wave generating means provided on both sides of the tags, in accordance with the position of a tag from which information is read; and phase shifting means for controlling the phase of at least one high-frequency signal so to produce the phase difference.

Tag reading method and apparatus

Distortion compensation coefficients for correcting distortion of a transmission power amplifier are stored in a memory beforehand, a distortion compensation coefficient conforming to powers or amplitudes of a present transmit signal and a past transmit signal is read out of the memory, and distortion compensation processing is applied to the transmit signal using this distortion compensation coefficient. The transmit signal thus subjected to distortion compensation processing is then amplified by the transmission power amplifier and the amplified signal is transmitted, and the distortion compensation coefficient is updated based upon the transmit signal before distortion compensation and an output signal from the transmission power amplifier.

Method and apparatus for compensating for distortion in radio apparatus

In a radio apparatus which compensates for non-linear distortion of a transmission power amplifier, a distributor feeds back the output signal of the transmission power amplifier, an error-signal estimating arithmetic unit digitally estimates an error signal, which is ascribable to non-linear distortion of the power amplifier, using a transmit signal and feedback signal, the transmit signal and the error signal are DA-converted by separate DA converters, and a combiner combines the output signals of the DA converters and inputs the combined signal to the transmission power amplifier to perform distortion compensation.

Radio apparatus having distortion compensating function

Disclosed is a radio apparatus in which modulating signals (I, Q signals) from an arithmetic/control unit are converted to analog signals, which are then applied to an orthogonal modulator. A modulated wave for transmission, which has been produced by orthogonally modulating a reference carrier wave by the modulating signals, is demodulated by the orthogonal detector. The arithmetic/control unit compares the modulating signals and the demodulated signals and, based upon the comparison, updates distortion compensation coefficients and applies pre-distortion processing to the modulating signal using the distortion compensation coefficients. Leakage carrier produced due to offset of the orthogonal modulator is detected and the arithmetic/control unit adjusts the level of the modulating signals or shifts the phase of the reference carrier wave in such a manner that the leakage carrier (offset) becomes zero.

Growing community of inventors

Kawasaki, Japan

Takeshi Takano