Matsushita Electric Industrial Co., Ltd.

The University of Electro-communications

Other

Optis Wireless Technology, LLC

Morikazu Sagawa

Mitsuo Makimoto

Masayuki Orihashi

Hiroyuki Yabuki

Akihiko Matsuoka

Kazuaki Takahashi

Michiaki Matsuo

Yutaka Murakami

Suguru Fujita

Sadahiko Yamashita

Makoto Hasegawa

Kenichi Maeda

Takashi Fukagawa

Naoki Adachi

Motoi Ohba

Yoshikazu Mori

Koji Wada

Kentaro Setsune

Akira Enokihara

Kouei Misaizu

Haruyoshi Endo

Takaaki Kishigami

Kaoru Inoue

Katsuaki Abe

Hiroshi Onishi

Kenichi Takahashi

Hiroyuki Sakai

Kazuhiro Eguchi

Yorito Ota

Shinichiro Ito

Makoto Takemoto

Hiromitsu Taki

Kuniaki Kiyosue

Toshiharu Noguchi

Fumio Fukushima

Takehiko Yoneda

Mitsuo Saito

Yoshihiko Takayama

Isao Ishigaki

Job Cleopa Msuya

Masayoshi Yoneyama

Eiichi Ochiai

Akiro Yoshida

Hirokazu Shirai

Keiichirou Kuwaduru

A transmission line resonator includes distributed coupled lines including first distributed constant line which one ends are connected to a short-circuit grounding portion and second distributed constant line which is disposed in parallel to the first distributed constant line while being separated therefrom by a predetermined distance and which one ends opposing the short-circuit grounded one ends of the first distributed constant line are connected to the short-circuit grounding portion, and a single transmission line which both ends are connected to the respective other ends of the distributed coupled lines.

Transmission line resonator, band-pass filter and branching filter

A transmission line resonator includes a half-wavelength stepped-impedance resonator with two ends short-circuited to ground, and a capacitive element with one end connected to a center portion of the stepped-impedance resonator and the other end short-circuited to ground. The stepped-impedance resonator includes a first transmission line, a second transmission line, and a third transmission line. The second transmission line has a second line impedance and a second line length, with one end being connected to one end of the first transmission line and the other end being short-circuited to ground. The third transmission line has the second line impedance and the second line length, with one end being connected to the other end of the first transmission line and the other end being short-circuited to ground. The first line impedance is lowered in comparison with the second line impedance.

Transmission line resonator, bandpass filter using transmission line resonator, multiplexer, balanced-to-unbalanced transformer, power divider, unbalanced-to-balanced transformer, frequency mixer, and balance-type filter

An input digital signal is periodically and alternately subjected to first modulation and second modulation, being thereby converted into a pair of a baseband I signal and a baseband Q signal. The first modulation and the second modulation are different from each other. The pair of the baseband I signal and the baseband Q signal are outputted. The first modulation may be at least 8-signal-point modulation while the second modulation may be phase shift keying.

Method for modulation and transmission apparatus

Modulation method and radio communication system

A phase of a sampling clock provided from clock generating circuitis switched periodically and alternately with a phase difference of 180 degrees, and during a period of each phase, timing estimating circuitestimates a symbol timing. High-accuracy timing estimating circuitselects an estimated result with higher reliability among symbol timing estimated results obtained in respective periods, thereby enabling estimation of the symbol timing with time resolution twice a sampling period. It is possible to decrease an operation frequency in an A/D conversion circuit even in a system requiring timing synchronization accuracy with high accuracy.

Reception apparatus and method

In a digital communication system such as a mobile radio system, fading distortion is compensated with a raised precision. In a transmitter, pilot signals are regularly inserted in the information signals. The amplitude of the pilot signals are set larger than the maximum possible amplitude of the information signals. The modulation scheme of the pilot signals may be different from that of the information signals. In a receiver, the fading distortion of each of the pilot signals is determined. The fading distortions of the information signals are estimated by interpolation using the determined fading distortion of the pilot signal, and then compensated. The frequency band of each information signal is preferably limited with a roll-off filter with a roll-off coefficient ranging from 0.1 to 0.4.

Pilot signal transmission technique and digital communication system using same

A hemispherical dielectric resonator is arranged on a metal substrate to make a flat surface of the hemispherical dielectric resonator contact with the metal substrate, and a dielectric wave-guiding channel is connected with a curved side surface of the hemispherical dielectric resonator. Therefore, a dielectric resonance antenna in which the hemispherical dielectric resonator and the dielectric wave-guiding channel are placed on the same metal substrate is obtained. A signal transmitting through the dielectric wave-guiding channel is fed in the hemispherical dielectric resonator, the hemispherical dielectric resonator is resonated, and an electromagnetic wave is radiated. Therefore, the dielectric resonance antenna functions as a wave radiation device.

Dielectric resonator antenna for a mobile communication

Nonlinear distortion compensating data is calculated by approximation equations at a compensating coefficient calculation section using an amplitude value of transmission quadrature base band signals obtained by a power calculating section, wherein by carrying out nonlinear distortion compensation at a nonlinear distortion compensating section using the data, it is possible to compensate nonlinear distortion generated in an amplifier of the transmission system without use of any memory table, and a nonlinear distortion compensating section can be obtained, which has a great effect of decrease distortion.

Transmission Apparatus

A hemispherical dielectric resonator is arranged on a conductive substrate with a flat surface of the resonator in contact with the conductive substrate and fixed by a pair of fixing blocks. The dielectric resonator is fed with a signal feeder at a position at one side of the resonator such that intensity of the electric field is higher at that position. The fixing blocks contact a portion of the dielectric resonator where the intensity of the electric field is of a local minimum.

A radio transmitter has a quadrature modulating portion and an RF power amplifier. The RF power amplifier follows the quadrature modulating portion. A nonlinearity-caused distortion compensating system provided in the radio transmitter includes a power calculating portion for calculating a value related to a power of a transmission signal from first baseband signals quadrature with respect to each other. First distortion compensating coefficients are determined in response to the calculated power-related value. The first distortion compensating coefficients are designed to compensate for a signal distortion caused by a nonlinearity of the quadrature modulating portion. Second distortion compensating coefficients are determined in response to the calculated power-related value. The second distortion compensating coefficients are designed to compensate for a signal distortion caused by a nonlinearity of the RF power amplifier. A compensation-coefficient calculating portion operates for calculating final distortion compensating coefficients from the first distortion compensating coefficients and the second distortion compensating coefficients. A distortion compensating portion operates for converting the first baseband signals into second baseband signals quadrature with respect to each other in response to the final distortion compensating coefficients to compensate for signal distortions caused by the nonlinearity of the quadrature modulating portion and the nonlinearity of the RF power amplifier. The second baseband signals are fed to the quadrature modulating portion.

Nonlinearity-caused distortion compensating system

A dielectric filter includes a dielectric block having multiple through holes which are created in parallel and grooves which are created around the opening of the through holes. A conductor is formed inside the grooves and the through holes. The inside conductors and in-groove conductors are connected at the opening of the through hole surrounded with the groove. The inside conductors and an outside conductor are connected at a second end. The opening of the through hole is formed inside an open-circuit end of the dielectric block.

Dielectric filter and RF apparatus employing thereof

A strip-line filter is provided with upper- and lower-stage resonators having the same electromagnetic characteristics. Each of the resonators has a one-wavelength square-shaped strip line and four open-end transmission lines connected to four coupling points A,C,B and D (or E,G,F and H) of each resonator which are spaced 90 degrees in electric length in that order. The square-shaped strip lines have a pair of parallel coupling lines closely placed in parallel to each other to electromagnetically couple the resonators. Therefore, the filter can be manufactured in a small size. A first microwave resonated in each resonator is electromagnetically influenced by two open-end transmission lines connected to two coupling points A and B (or E and F), and a second microwave resonated in each resonator is electromagnetically influenced by two open-end transmission lines connected to two coupling points C and D (or G and H). Therefore, resonance wavelengths of the microwaves can be longer than a line length of each square-shaped strip line. Also, the resonance wavelengths can be adjusted by trimming the transmission lines. Also, because all constitutional elements are made of strip lines, the filter can be made plane.

Plane type strip-line filter in which strip line is shortened and mode resonator in which two types microwaves are independently resonated

Growing community of inventors

Tokyo, Japan

Morikazu Sagawa