Hitachi, Ltd.

Hitachi Cable, Inc.

Hitachi Metals, Ltd.

Panasonic Liquid Crystal Display Co., Ltd.

Hitachi Displays, Ltd.

Hitachi Media Electronics Co., Ltd.

Ken Takei

Hiroshi Okabe

Tomoyuki Ogawa

Kenji Sekine

Takahiro Sugiyama

Masami Ohnishi

Yuji Ishida

Yoshinori Nagoya

Hiroshi Kageyama

Yohei Shirakawa

Futoshi Furuta

Mikio Kuwahara

Kazuyuki Hori

Makoto Katagishi

Hiroyuki Aoyama

Morihiko Ikegaya

Satoshi Adachi

Ikuo Murata

Hiroshi Kishida

Masumi Iwamura

Yoshitaka Imakado

Satoshi Takahashi

Hideki Kambara

Mitsuo Usami

Tsutomu Yamada

Toshiro Suzuki

Masao Kamahori

Kiichi Yamashita

Yoshiaki Yazawa

Hiroshi Kondoh

Osamu Kamimura

Masahiro Aono

Eriko Takeda

Nobuaki Kitano

Seiichi Kashimura

Yuuji Ishida

Hiroyuki Hori

Keisuke Fukuchi

Hiroshi Usami

Kazuo Tamura

Koji Fukamachi

Toshimasa Kawamura

Ryota Yamazaki

Takashi Sakai

Tomonori Nomura

Yasuo Ishikawa

A controller of a transmitter outputs cyclically different digital data to equivalent transmission circuits, that is, RF circuits to generate a rotation polarized wave.

Transmitter

A wireless communication system that communicates by an electromagnetic wave includes a first wireless device that includes a transmission rotationally polarized wave frequency generator for giving a rotation period to a polarized wave of the electromagnetic wave to be transmitted, transmits a synchronization code by the electromagnetic wave of the polarized wave rotated using the transmission rotationally polarized wave frequency generator, and transmits data by the electromagnetic wave, and a second wireless device that includes a reception rotationally polarized wave frequency generator for giving a rotation period to the polarized wave received in a reception of the electromagnetic wave, calculates transmission timing of the synchronization code included in the received electromagnetic wave of the polarized wave rotated using the reception rotationally polarized wave frequency generator, and sets a signal included in the received electromagnetic wave, as data based on the calculated transmission timing.

Wireless communication system and wireless surveillance control system

A transmitter includes: a first transmission block that generates a first radio wave having an information signal modulated thereon and having a plane of polarization that rotates; and a second transmission block that generates a second radio wave having the information signal modulated thereon and having a plane of polarization that is fixed. A receiver includes: a first receive section that demodulates a first radio wave having an information signal modulated thereon and having a plane of polarization that rotates; and a second receive section that demodulates a second radio wave having the information signal modulated thereon and having a plane of polarization that is fixed. The receiver restores the information signal on the basis of the result of reception by the first receive section and the second receive section.

Transmitter and receiver

There is provided a radio communication system configured to communicate with the electromagnetic wave. The radio communication system includes a plurality of slave stations, each configured to transmit and receive the electromagnetic wave using the fixed polarized wave, and a master station including an antenna and a base band circuit, the master station configured to identify a polarization direction of the electromagnetic wave reaching the antenna and a slave station transmitting the electromagnetic wave and notify the identified slave station of a communication timing based on an identified polarized direction. The plurality of slave stations include a plurality of slave stations arranged such that electromagnetic waves transmitted from a plurality of slave stations among the plurality of slave stations reach the antenna of the master station in a plurality of different fixed polarization directions.

Radio communication system and radio monitoring control system

A highly-secure wireless communication system has a transmitter for transmitting the same information at predetermined polarized wave angles having different rotation-polarized waves for rotating the polarized waves of a carrier wave, and a receiver for restoring the reception information at the aforementioned predetermined polarization wave angles and for comparing the restoration results of the predetermined polarization wave angles with one another.

Highly-secure wireless communication system

In a thin rotationally polarized antenna which performs highly reliable and highly secure wireless communication, in the case where a feeding point is provided in an integrated plate conductor including a plurality of minute conductor segments and is excited at a first frequency and a second frequency different from the first frequency, matching with a feeding circuit is achieved in both a frequency band including the first frequency and a frequency band including the second frequency. Current distribution formed in orthogonal directions on the plate at the first frequency has the same amplitude and has a phase difference of 90 degrees. Current distribution formed in the same orthogonal directions on the plate at the second frequency has the same amplitude and has a phase difference of 90 degrees, and a phase of the current distribution at the first frequency and a phase of the current distribution at the second frequency have opposite directions.

Rotationally polarized antenna, transmission/reception module, elevator control system, and substation control system

A wireless communication system includes a plurality of wireless devices that communicate with each other. Each of the wireless devices includes a transmission unit configured to transmit a carrier of a fixed strength with polarization waves thereof rotated to a different one of the wireless devices using two antennae spatially orthogonal to each other, a reception unit configured to receive a carrier transmitted from the transmission unit of the different wireless device, and a timing detection unit configured to detect a timing at which the polarization waves of the carrier received by the reception unit within a period of rotation indicates a maximum strength. The transmission unit performs transmission or reception of a specific information signal using the carrier based on the timing detected by the timing detection unit.

Wireless communication system having a transmission unit that transmits or receives based on a detected timing

In a wireless communication system, wireless communication devices are disposed, each including two orthogonal antennas, a transmitter, and a receiver using rotating polarized wave having a changeable transmission frequency. Specific codes are assigned to the devices, respectively and are shared. In a first of the devices, information and a first code are superimposed on a first carrier wave. In a second of the devices, the transmitted wave is received to reproduce the information with the codes assigned to the second device and the shared code assigned to the first device. The second device transmits second information through modulation using the code thereof. Each of the first and second devices adjusts the propagation frequency for a maximum ratio in intensity of a signal reproduced with the code assigned to another device to an intensity of a signal reproduced with the code assigned to the own device.

Wireless communication system, shielded yard wireless communication system, and wireless communication device

A wireless system allows for selectively using, and communicating through, wireless propagation paths between radio devices in an over-the-horizen communication environment. Also an elevator control system and a substation monitoring system using the same are provided. The wireless system includes a transmitter having: two spatially orthogonal antennas; and a transmission circuit that transmits a signal having an information signal spread with one code and then superimposed on a circularly-polarized wave, along with a signal having the same information signal spread with two different codes and then superimposed on orthogonal statically-polarized waves, which are orthogonal to each other, and a receiver having: at least one antenna; and a reception circuit that takes a difference between the sum of two operation results obtained by despreading with two different codes a signal received through statically-polarized waves, and an operation result obtained by despreading with one code a signal received through a circularly-polarized wave.

Wireless system, and elevator control system and substation monitoring system including same

Provided is a wireless communication system that achieves high-reliability communication between a transmitter and a receiver. Specifically, the wireless communication system includes: a transmitter that transmits a carrier wave with rotational polarization on which a strongly correlated code is superimposed; and a receiver that uses the strongly correlated code in the reception polarized wave from the transmitter to establish synchronization between the transmitter and the receiver, wherein the receiver receives signals in a plurality of different polarized waves, establishes synchronization between the transmitter and the receiver for the plurality of reception polarized waves using correlation values between the received signals and the strongly correlated code corresponding to the reception polarized waves, compares the correlation values to a threshold to extract a specific reception polarized wave and a received signal corresponding to the polarized wave, calculates transmission polarization angles from shifts in synchronization timing, and separates or selects the signals transmitted in different propagation paths using specific reception polarized waves corresponding to the plurality of transmission polarization angles and the received signals corresponding to the polarized waves.

Wireless communication system and system using same

A radio device includes a transmitter and a receiver. The transmitter transmits rotationally polarized radio waves in a plurality of transmission propagation directions using a plurality of antennas. The receiver receives rotationally polarized radio waves in a plurality of reception propagation directions using a plurality of antennas. The receiver measures changes in rotational loci of polarizations of the radio waves received in the plurality of reception propagation directions corresponding to radio waves transmitted in a plurality of transmission propagation directions. The transmitter performs transmission using a reception propagation direction at which the changes measured by the receiver in the rotational loci of the polarizations of the received radio waves stop.

Radio communication system, elevator control system using same, and substation facility monitoring system

A wireless communication system is disclosed by which, in communication that uses rotationally polarized waves, the information transmission amount is increased to perform communication. A transmittertransmits a signal using polarized waves that are different at different timings using a rotationally polarized wave. In a receiver, a reception baseband circuitdetects different polarized waves received at timings corresponding to the polarized waves used by the transmitteron a time axis using a plurality of signals equivalent to the received signals to obtain a wireless propagation characteristic between the transmitterand the receiver. Then, the transmitterpropagates different signals in the form of a plurality of polarized waves at the same time using a plurality of rotationally polarized waves having initial polarization rotation phases different from each other. The transmission capacity can be increased by an amount corresponding to the number of different signals.

Wireless communication system

A radio power transmission apparatus comprises a transmitterhaving a power transmitting antennafor transmitting electromagnetic waves and a power transmitting circuit and a receiverhaving a power receiving antennafor receiving electromagnetic waves and a power receiving circuit. In the radio power transmission apparatus, on the basis of power reflected to the power transmitting antenna, the power transmitting circuit executes control to change the circuit reactance of the power transmitting circuit in order to control the imaginary part of power of the electromagnetic waves to be transmitted. In addition, on the basis of a value of power transmitted to the transmitterby using electromagnetic waves of power transmission used by the receiverto transmit a value of power received by the receiverthrough the power receiving antenna, the power transmitting circuit executes control to change the circuit reactance of the power transmitting circuit or the characteristic impedance of the power transmitting circuit in order to control the real part of power of the electromagnetic waves to be transmitted.

Radio power transmission apparatus and radio power transmission system

[Object] A wireless communication system capable of detecting propagation path modification from the outside and compensating for degradation of quality of communication between transmission and reception with respect to the propagation path modification is provided. A wireless communication system includes a transmitter that transmits electromagnetic waves in which a polarization direction rotates according to a signal in which data is loaded on a carrier, and a receiver that receives the electromagnetic waves and demodulates the data, in which the transmitter imparts angle information indicating a polarization direction for transferring the data to the signal, and sets a rotation frequency of the polarization direction to a frequency lower than a frequency of the carrier, and the receiver changes a polarization direction of the received electromagnetic waves, based on the angle information transferred by the electromagnetic waves. The receiver can detect propagation path modification from the outside using the angle information of the polarization direction, and compensate for degradation in quality of communication between transmission and reception by changing the polarization direction of the received electromagnetic waves when the modification is detected.

A wireless transmitter has a modulator modulating an information signal of a frequency f1 by a carrier wave of a frequency f2 to output a first modulated signal, a transmitting antenna transmitting the first modulated signal using a linearly polarized wave, and a motor rotating the transmitting antenna at a frequency f3 to rotate the outgoing linearly polarized wave at the frequency f3 thereby multiplexing the first modulated signal with a linearly polarized wave component and a horizontally polarized wave component, the two components being independent of each other. A wireless receiver has diversity receiving antennas receiving the signal on a plurality of polarization planes to obtain a plurality of input signals; a path difference phase shifter compensating each of the input signals for the phase shift stemming from path differences, and a composer composing the corrected received signals.

Polarization-angle-division diversity wireless transmitter, wireless receiver, and wireless communication system

Growing community of inventors

Kawasaki, Japan

Ken Takei