Nippon Telegraph and Telephone Corporation

Osamu Kagami

Ai-ichiro Sasaki

Fumiharu Morisawa

Hiroki Morimura

Akihiko Hirata

Tsutomu Mizota

Souichi Oka

Yosuke Fujino

Takafumi Fujita

Daisei Uchida

Kozo Morita

Masahiro Umehira

Kazuji Watanabe

Ai-Ichiro Sasaki

Provided is a loop antenna array that can easily create a magnetic field distribution which enables the boundary of a communication area to be clearly set.loop antennae are provided adjacently to one another, where n is a natural number. The directions of currents in adjacent ones of the loop antennae are opposite to each other. For example, in a loop antenna array, two loop antennae are disposed adjacently to each other on an insulator substrate. First feed points energize one loop antenna and second feed points energize the other loop antenna.

Loop antenna array and loop antenna array group

A loop antenna array capable of forming a clear boundary of a communication area is provided. The loop antenna array includes three loop antennas, in which a direction of a current flowing through the loop antenna arranged in the middle and a direction of a current flowing through each of the loop antennas arranged on both sides of the loop antenna arranged in the middle are opposite from each other, and the sum of magnetic moments of the three loop antennas is zero.

Loop antenna array

Provided is a loop antenna which can contribute to an increase of an area of a radio system using a magnetic field. The loop antenna includes a main loopwhich is an open loop connected to a signal sourceor a reception circuit; and an amplification loopwhich is a closed loop having the same shape as the main loop. The main loopand the amplification loopare arranged on a same surface of a flat substrate formed of an insulator. A first capacitance is connected to the main loop, and a second capacitance is connected to the amplification loop.

Loop antenna

A main loop is an open loop that is wound on a bar-shaped rod formed of a magnetic body or an insulation body and that has terminals T and T that couple a signal source or a receiving circuit to the main loop. The number of turns is 1 or more. An amplifying loop is wound on a part of the rod that is different from the part on which the main loop is wound. The main loop and the amplifying loop are thus spaced from each other. The amplifying loop is a closed loop including no terminals. The number of turns is 1 or more. The number of turns may be the same as or different from the number of turns of the main loop.

A loop antenna array that can form a linear and clear communication area boundary is provided. The loop antenna array includes two loop antennas. Currents flow through the loop antennas in opposite directions from each other. In other words, viewing in a direction passing through each of the loop antennas, at a timing when a positive voltage is applied to a signal terminal of an alternating-current source, a clockwise current flows through one loop antenna while a counterclockwise current flows through the other loop antenna. Conversely, at a timing when a negative voltage is applied to the signal terminal of the alternating-current source, a counterclockwise current flows through one loop antenna while a clockwise current flows through the other loop antenna.

Provided is an antenna control technique for forming the boundary of a communication area at a desired location. An antenna parameter control apparatuscalculates an antenna parameter in a case of feeding electric currents with an equal intensity in mutually reverse directions to two antennasA,B which generate a magnetic field. The antenna parameter control apparatusincludes an input parameter acquisition unitthat acquires input parameters for calculating the antenna parameter; and a parameter calculation unitthat calculates an inter-center distance d between the antennasA,B as the antenna parameter based on the input parameters.

Antenna control apparatus, antenna control program, and antenna control system

A wireless transmitting apparatus inserts a training signal into a transmission burst at fixed symbol intervals as a pilot signal, a wireless receiving apparatus performs AD conversion of a received burst signal, performs symbol timing recovery, performs frame position detection and pilot signal extraction from the received burst signal for which symbol timing was established, performs frame synchronization, and performs a carrier frequency estimation using pilot signal. A carrier frequency estimation is also performed with respect to a received burst signal for which frame synchronization was established, and channel distortion is estimated and output based on a frequency-corrected received burst signal. Channel distortion estimation is then performed with respect to a frequency-corrected received burst signal, and a data symbol sequence of the channel-compensated received burst signal is converted to a received data bit stream.

Wireless transmitting apparatus, wireless receiving apparatus, wireless transmission method, wireless reception method, wireless communication system, and wireless communication method

A digital radio-relay system has a transmitting terminal station, at least one repeater station a receiving terminal station, a non-regenerative repeater station which does not regenerate a digital signal in order to simplify and reduce cost of the system, while keeping excellent signal quality in transmission. Each repeater station has a plurality of sub-units relating to respective sub-system signals each having a plurality of carriers so that the frequency spectrum of each sub-system signal is allocated on a frequency axis based upon a frequency division multiplex system. A repeater station having a first frequency converter to convert a received radio frequency to IF frequency, bandpass filters for deriving one of the carriers in each sub-system signal, amplifiers to amplify the derived carrier on IF band stage, and a second frequency converter to convert the IF frequency to radio frequency, has a common reference oscillator which generates a reference frequency which is a common divisor of all the local frequencies for all the radio frequencies of all the sub-system signals. Only one of an upper and lower heterodyne signals is taken in all the frequency conversions, so that distortion in each relay section is added in-phase. Leaked noise caused by the bandpass filters is added to original carrier in-phase. All the distortion thus added in the relay sections can be compensated by a transversal equalizer in the receiving terminal station. Therefore, excellent signal quality is obtained although a simple non-regenerative repeater station is used.

Growing community of inventors

Atsugi, Japan

Osamu Kagami