Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Masahiro Maki

Yuji Igata

Mutsuhiko Oishi

Toshiyuki Wakisaka

Satoshi Hasako

Akihiro Yamashita

Fumio Ichihara

Tsunehiro Hanada

Michinori Kishimoto

Shoichi Koga

Hisao Koga

Tomohiro Kimura

Akio Kurobe

Shigeo Yoshida

Junji Kondou

Satoshi Shinozaki

Nobutaka Kodama

Ryota Yukizane

Kazuhiko Tamesue

Kazuaki Kusune

Hidekazu Matsunobu

A first communication apparatustransmits a pilot signal which was generated by a pilot signal generation section, at predetermined timing, and detects an unbalance component of a transmission lineat the time of pilot signal transmission in an unbalance component detection section, and controls a transmission signal in such a manner that an unbalance component is reduced by a transmission control sectionon the basis of the detected unbalance component.

Line status detection apparatus, communication apparatus, and line status detection method

A line state detecting apparatus provided in a balanced transmission system includes, in transmission lines comprising a pair of conductors WWconnected to a transmitting portioncurrent transformers TTprimary sides of which are inserted to respectives thereof in series therewith and secondary sides of which are connected in series to cancel currents or voltages of the two transformer by each other, and a detecting portionfor detecting currents or voltages on secondary sides of the current transformers TT. By an output of the detecting portiona difference of currents or voltages of the conductors WWof the transmission lines is provided and an unbalance component between the conductors WWis detected.

Line state detecting apparatus and transmitting apparatus and receiving apparatus of balanced transmission system

A balanced transmission signal Tx (t) (voltage e, &#x2212;e) is applied to a transmission line (L, L), a suppression signal (e) is generated from a common mode suppression signal source (e), and the suppression signal (e) is superposed on respectives of balanced transmission signals via adders (). By pertinently controlling a level of the suppression signal (e), voltage levels and phases of respectives of the transmission signals transmitted to the transmission lines (L, L) are controlled.

Balanced transmitting apparatus

A communication network system sets communication parameters which enable an operation under a maximum possible communication rate in a situation where a transmission path has cyclic noise/impedance fluctuations. A transmission/reception apparatustransmits training packets for checking the state of the power line at two distinct points in time. A transmission/reception apparatus analyzes SNR at each carrier frequency, and stores an SNR evaluation result. The transmission/reception apparatus compares two SNR evaluation results which are obtained through two instances of a channel estimation algorithm, selects an SNR evaluation result which dictates a faster PHY rate, and transmits it to the transmission/reception apparatus. The transmission/reception apparatus changes modulation/demodulation rules based on the received SNR analytical result.

Communication network system, and transmission/reception apparatus, method and integrated circuit for use therein

A multicarrier communication method selects carriers on the basis of an SN-ratio and the balancing of a transmission line. Available carriers are selected in accordance with the balancing of the balanced transmission line, in which the balancing is measured at either a sending terminal or a receiving terminal or alternatively at both, and the SN-ratio is measured between the sending terminal and the receiving terminal. Additionally, a modulation method having the greatest permissible multivalue is selected for each of the carriers, wherein the carriers are selected in light of the SN-ratio and balancing, or alternatively in a highest-to-lowest order of frequency. Transmission power is controlled for each of the carriers to suppress radiated emission, and the SN-ratio and balancing are measured at predetermined time intervals to renew the selection of the carriers and the selection of the modulation methods.

Multicarrier communication method and system, and communication apparatus incorporated therein

A communication network system sets communication parameters which enable an operation under a maximum possible communication rate in a situation where a transmission path has cyclic noise/impedance fluctuations. A transmission/reception apparatus transmits training packets for checking the state of the power line at two distinct points in time. A transmission/reception apparatus analyzes SNR at each carrier frequency, and stores an SNR evaluation result. The transmission/reception apparatus compares two SNR evaluations results which are obtained through two instances of a channel estimation algorithm, selects an SNR evaluation result which dictates a faster PHY rate, and transmits it to the transmission/reception apparatus. The transmission/reception apparatus changes modulation/demodulation rules based on the received SNR analytical result.

It is an object of the invention to provide a communication apparatus, a communication system and a communication method enabling efficient transmission in accordance with a situation of a wired transmission line and capable of reducing an influence by a radiation power of the transmission line. The communication apparatus of the invention executes wired transmission using a plurality of sub carriers and includes a transmission signal generator for generating a transmission signal, and a transmission signal controller for controlling a transmission power of the transmission signal generated by the transmission signal generator based on a radiation power in a transmission line in correspondence with a frequency of the sub carrier, and a transmitter for transmitting the transmission signal the transmission power of which is controlled by the transmission signal controller via the transmission line.

Communication apparatus, communication system and communication method

A radiation information management device comprises a measuring unit, a comparing unit, and a management information generating unit. The measuring unit measures unwanted radio wave radiation radiated from a balanced transmission line. The comparing unit compares a measured value of unwanted radio wave radiation, which the measuring unit has measured, with a reference value that is predetermined, and then notifies the comparison result to the management information generating unit. The management information generating unit refers the comparison result, generates the management information related to the unwanted radio wave radiation including information showing that the measured value is exceeded the reference value, then notifies to a first communication device and a second communication device. The first communication device and the second communication device take a measure to reduce transmitting power based on the management information regarding the unwanted radio wave radiation. Thus, in the first communication device and the second communication device, the unwanted radio wave radiation radiated from the balanced transmission line can be controlled within the reference value.

Radiation information management device and communication device

A display device comprises an inspection circuit for inspecting a data reception related circuit to generate inspection information, an inspection result image generation circuit for generating image data indicating the inspection information, a display switching circuit for superimposing inspection result image data on test video data, and a display unit for displaying the test video data superimposing the inspection result image data. As a result, it is possible to carry out inspection after assembly of the display device without disassembling the display device. This in turn makes it possible to carry out a test in a simple manner on the data reception related circuit inside the display device without changing noise environment inside the display device.

Display device, receiver, and test apparatus

Impedance values of a common mode choke coil, an impedance element disposed anterior to the common mode choke coil and an impedance element disposed posterior to the common mode choke coil are determined in such a manner that a common mode current flowing into the common mode choke coil does not exceed a value of rated current. Excessive common mode current is prevented from flowing into the common mode choke coil, and saturation and damage of the common mode choke coil is prevented.

Balanced transmission termination device and receiver unit composed thereof

To use high noise transmission lines, such as an electric wire, as the lines to transmit signals, it is imperative to reduce the level of signals. The present invention is provided with a sending signal generating means , which outputs converted data after converting an input signal into a plurality of carrier signals assuming values at such intervals on the axis of frequency that the frequencies may not interfere with each other. If an interfering noise with any one of the plurality of frequencies arises on the transmission line, removal of only a carrier of the noise frequency would leave the communication in a good condition. Furthermore, better results can be hoped for if the respective carrier signals are so arranged as not to interfere with each other or so arranged to intersect orthogonally with each other not only on the axis of frequency but also on the axis of time

Communication systems, sender and receiver

A highly reliable and high-speed data transmission is made by using an FH or MFSK mode as suitably selected according to the usage of channels. When a reception signal is entered into a receiver through a transmission line, (i) a signal processing unit supplies the spectrum intensity values of carrier frequencies, (ii) a channel detection unit controls the phase of a time slot based on the spectrum intensity values, selects the MFSK or FH modulation mode, and supplies reception code data corresponding to detected carrier frequencies, and (iii) a decoder supplies reception information data based on the reception code data. When transmission information data are entered into a transmitter, (i) a coding unit supplies, according to the selected modulation mode, transmission code data based on the transmission information data, (ii) a channel generation unit supplies, based on the transmission code data, carrier frequencies to be used and (iii) a waveform generation unit supplies a transmission signal to a transmission line.

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Kasuya-gun, Japan

Masahiro Maki