Panasonic Corporation

Matsushita Electric Industrial Co., Ltd.

Mutsuhiko Oishi

Masahiro Maki

Fumio Ichihara

Toshiyuki Wakisaka

Akihiro Yamashita

Tsunehiro Hanada

Hisao Koga

Yuji Igata

Ryota Yukizane

Tomohiro Kimura

Nobutaka Kodama

Akio Kurobe

Shigeo Yoshida

Hidekazu Matsunobu

Kazuaki Kusune

Isao Matsugaki

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 relay apparatus includes a plurality of connecting terminals, such as a modem connecting terminal, a power line connecting terminal, an electric appliance connecting terminal and an antenna line connecting terminal; a selector that selects at least one connecting terminal from among the plurality of connecting terminals to transmit and receive a communication signal; and a control circuit that controls the selector. The relay apparatus further includes a first communication filter that passes signals in a frequency band used for communication by a power line communication modem and that blocks signals in other frequency bands, and a second communication filter that passes signals in a frequency band used for communication by another electric appliance and that blocks signals in other frequency bands.

Relay apparatus and electric appliance

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

Provided is a multi-carrier communication apparatus, power line communication circuit, and multi-carrier communication method capable of decreasing omission of carrier detection even when a plurality of communication apparatuses are simultaneously transmitting signals at the state of time discord. Digital signals transmitted from a digital signal-processing unitare converted into analog signals by an analog circuit unitand then transmitted from a pair of linesandvia a communication transformer. The digital signal-processing unithas a frequency carrier detecting unitwhich detects the existence of a carrier on the basis of a frequency characteristic of the received signal and the frequency carrier detecting unitdetects the carrier by taking correlation between sub-carriers adjacent to each other at every other interval.

Multi-carrier communication apparatus, power line communication circuit, and multi-carrier communication method

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 receiver and a phase extraction circuit are capable of demodulating at high resolution if the sampling frequency is close to the frequency of received signal. In the phase extraction circuit, the received signal modulated in phase is sampled when lowered to an intermediate frequency. When the sampling frequency at this time is selected around the intermediate frequency, a continuous portion appears in one position of the sampling data row. The position of the continuous portion is determined by the phase of the received signal, and therefore a one-to-one correspondence table of the continuous position and phase of received signal is prepared. By detecting the continuous position, the phase information can be obtained from the table. As a result, it is possible to demodulate directly at the intermediate frequency, and therefore the circuit scale is substantially simplified, the number of parts is curtailed, and the size is reduced.

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Fukuoka, Japan

Mutsuhiko Oishi