Ntt Mobile Communications Network, Inc.

Ntt Docomo, Inc.

Nippon Telegraph and Telephone Corporation

Japan Radio Co., Ltd.

Hitachi-kokusai Electric Inc.

Nec Corporation

Nippon Telegraph and Telephone Public Corporation

Nippon Telephone and Telegraph Corporation

Nippon Telegraph & Telephone Co.

Nippon Telephone & Telephone Corporation

Toshio Nojima

Yasunori Suzuki

Yoshiaki Tarusawa

Shoichi Narahashi

Hironori Sakamoto

Yoichi Okubo

Noriyoshi Terada

Ken Kumagai

Yasushi Yamao

Manabu Nakamura

Kei Satoh

Taizo Ito

Akira Ito

Sadayuki Nishiki

Shinji Uebayashi

Ryo Yamaguchi

Yasuhiro Takeda

Ning Chen

Tetsuo Hirota

Junya Dosaka

Takahiro Iyama

Kazuaki Murota

Makoto Maeta

Toshio Suzuki

Atsushi Fukuda

Kunihiro Kawai

Tadao Takami

Masaru Adachi

Motoyuki Uchida

Masatoshi Ishida

Shigeki Saito

Yasuo Sera

Terufumi Nagano

Shigeru Tomisato

Hisao Takahashi

Hidekatsu Ueno

Teruya Fujii

Nobuaki Imai

Kouji Chiba

Satoru Ohara

Masaaki Fujiwara

Yasushi Ito

Satoshi Ohyama

Hitoshi Odate

Fumitake Kawanabe

Tetsuya Mimura

Yoshinori Fujiki

An amplifier capable of lowering an electrical current flowing in a peak amplifier before a carrier amplifier becomes saturated to thereby improve the efficiency of an entirety of the amplifier is provided. The amplifier includes a carrier amplifier circuit having an amplifying element operable in class-AB or class-B, and a plurality of peak amplifier circuits which have amplifying elements operating in class-B or class-C and which are arranged to start an operation in stages in response to an input level. An output of the carrier amplifier circuit and outputs of the peak amplifier circuits are combined together for signal output. One of the peak amplifier circuits which is rendered operative at the lowest input level is smaller in saturation output than the carrier amplifier circuit.

Amplifier apparatus

A high frequency power amplifier includes an amplifying device for amplifying an input high frequency signal, a harmonic reflection circuit for reflecting a harmonic outputted from the amplifying device, and a harmonic generating circuit provided at an input terminal of the amplifying device, the harmonic generating circuit including a divider for dividing an input signal of a fundamental wave into two parts, a harmonic generator for generating a second harmonic from one part of the fundamental wave signal, and a combiner for combining the second harmonic generated from the harmonic generator with the other part of the fundamental wave signal to offer a combined signal to the amplifying device, wherein the harmonic reflection circuit reflects the second harmonic.

High frequency power amplifier

The performance of an amplifying system is improved by achieving adequate matching. The amplifying system for amplifying signals includes distributing meansthat distribute a signal, a carrier amplifierthat amplifies the distributed first signal in Class AB, a peak amplifierthat amplifies the distributed second signal in Class B or Class C, a first transmission line having a given electric length and being connected to an output of the carrier amplifier, a second transmission line having a given electric length and being connected to an output of the peak amplifier, and a combining endfor combining an output of the first transmission line and an output of the second transmission line. An impedance of the combining end is differentiated from a parallel impedance of load impedances of the carrier amplifier and the peak amplifier at the maximum power converted respectively by the first transmission line and the second transmission line, or is set as a parallel impedance in which the load impedances of the carrier amplifier and the peak amplifier at the maximum power are changed.

Amplifying system

A distortion compensation apparatus includes distortion generating means for generating distortions to compensate for a distortion generated in an amplifier. The distortion generating means includes a nonlinear circuithaving an input/output expansion characteristic as a circuit which generates a distortion of the lowest odd order as a compensation target and also includes a nonlinear circuithaving an input/output saturation characteristic as a circuit which generates a distortion of another odd order as a compensation target.

Distortion compensation apparatus

In an apparatus for measuring absorbed power including an electromagnetic field probefixedly mounted within a head simulation phantomwhich simulates the configuration and the electromagnetic characteristics of a head of a human body, and wherein the strength of an electric field or a magnetic field of a radio wave externally irradiated upon the head simulation phantomis measured by the electromagnetic field probe, and the power of the radio wave absorbed by the head is estimated on the basis of measured values, the head simulation phantomcomprises a solid dielectric' which simulates the configuration and the electromagnetic characteristics of a head of a human body or a liquid dielectricwhich simulates the electromagnetic characteristics of a head of a human body and which is filled in an enclosed vesselwhich simulates the configuration of a head of a human body. The volume of the solid dielectric&#x2032; or the volume of the enclosed vesselis equal to or less than 5&#xd7;10mm.

Apparatus for measuring absorbed power

The invention relates to a high sensitivity receiver installed outdoors which may be used in a base station of a mobile communication system, for example. A received radio frequency signal is converted into a signal in a desired frequency band by a reception bandpass filter RXF, is subject to a low noise amplification to a desired level by a low noise reception amplifier LNA, and the amplified signal is converted into an optical signal by a laser diode LD. RXF, LNAand LDare confined in a heat shielding box. LDis cooled by cooling means to the order of critical temperature where RXF, for example, assumes a superconducting state, whereby the dynamic range is increased and stabilized.

High sensitivity radio receiver

Different carrier frequencies are chosen for plural transmitters of a transmitting device and signals are transmitted at frequency bands overlapping each other. In the receiving device weighting coefficients are provided in input-to-output paths of an interchannel interference cancellerso that the cross correlation between output signals from the interchannel interference canceller is minimized.

Radio communication method and apparatus for multiplex transmission of plural signals in the same frequency band

To provide a super directional gain in a multi-element array antenna. An array antenna comprising a plurality of antenna elements A-&#x2013;A-spaced at intervals (equal to or less than a quarter of a wavelength) that provides a supergain is used. A weight generator circuit generates weight data in accordance with phase difference and amplitude difference among the antenna elements A-&#x2013;A-and directivity data of each of the antenna elements A-&#x2013;A-The generated weight data is used to weight each of the antenna elements A-&#x2013;A-

Supergain array antenna system and method for controlling supergain array antenna

In an apparatus for measuring absorbed power including an electromagnetic field probefixedly mounted within a head simulation phantomwhich simulates the configuration and the electromagnetic characteristics of a head of a human body, and wherein the strength of an electric field or a magnetic field of a radio wave externally irradiated upon the head simulation phantomis measured by the electromagnetic field probeand the power of the radio wave absorbed by the head is estimated on the basis of measured values, the head simulation phantomcomprises a solid dielectric' which simulates the configuration and the electromagnetic characteristics of a head of a human body or a liquid dielectricwhich simulates the electromagnetic characteristics of a head of a human body and which is filled in an enclosed vesselwhich simulates the configuration of a head of a human body. The volume of the solid dielectric&#x2032; or the volume of the enclosed vesselis equal to or less than 5&#xd7;10mm.

Absorption power measuring device

A radio communication system is comprised of: a transmitting system in which N transmission signals, frequency-converted to the same transmission frequency, are generated by N transmitters, N being an integer equal to or greater than 2, and the transmission signals are each applied to each one of N elements of an antenna for transmission; and a receiving system in which each transmitted signal is received by N-element antenna and the cross correlation coefficient between the transmitted signals received by the N-elements is minimized to thereby reconstruct each transmitted signal. The plural transmitted signals of the same frequency are received and the cross correlation coefficients of the received transmitted signals are minimized to thereby permit multiplexing of the transmission signal.

Space multiplex radio communication method and radio communication apparatus

A divider/combiner unit combines RF signals, then converts the combined signal into an optical signal and sends it over an optical fiber. N radio access units each convert the optical signal received from the optical fiber into an RF signal and transmits it from an antenna, and each radio access unit converts an RF signal received by the antenna into an optical signal and sends it over an optical fiber to the divider/combiner unit. The divider/combiner unit converts the received optical signal into RF signals and outputs them. This system is operated as plurality of communication systems in common to them in correspondence to a plurality of input/output terminals of the divider/combiner unit.

Communication system using optical fibers

In a high sensitive radio receiver system for a diversity reception from two antennae per each of three sectors (SC, SC, SC), a series connection of a bandpass filter (to) and a low noise amplifier (to) is contained in each of a plurality of vacuum chambers (to), the interior of which is cooled by a distinct, separate cooling unit (to). The two antennae per sector are connected to bandpass filters contained in different vacuum chambers.

High-sensitivity wireless receiving device and high-frequency unit used therefor

A mobile communication base station determines the oncoming direction of a radio wave with a simple arrangement and transmits a narrow angle beam in this direction. Received signals from a pair of wide angle beam antennae-and-having an equal configuration and a common orientation and which are located close to each other are fed to a direction finder receiverand a communication receiver. By utilizing the fact that the both received signals have a coincident amplitude, a phase difference between the received signals is detected. The oncoming direction of the received radio wave (or the direction of a mobile station) is determined on the basis of the phase difference. A beam switcheris controlled so as to connect a transmitterto a narrow angle beam antenna (one of-to-) which is directed in the oncoming direction thus determined.

Mobile communication base station equipment

In a feedforward amplifier with a dual loop in which a distortion injection path of a distortion elimination circuitis provided as a feedforward configuration composed of a first auxiliary amplifier distortion elimination circuitand a first auxiliary amplifier distortion elimination circuit, a second variable attenuatorand a second variable phase shifterare provided preceding the distortion detection circuita second pilot signal injected between stages of a main amplifieris detected by a directional couplerand the second variable attenuatorand the second variable phase shifterare controlled by a second controllerto minimize the level of the detected second pilot signal, thereby bringing the distortion elimination circuit and the first auxiliary distortion detection circuit into balance at the same time.

Feedforward amplifier with dual loop

In an input signal power dynamic range compressing circuit, an input signal is distributed by a directional coupler to a linear signal transfer path and a compressing signal generating path, and in the compressing signal generating path a compressing signal, which keeps the peak-to-average-power ratio of the input signal below a predetermined value, is generated from the input signal. The compressing signal is combined by a power combiner with the input signal having passed through the linear signal transfer path.

Signal power dynamic range compressing circuit and power amplifier using the same

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Sapporo, Japan

Toshio Nojima