Abstract: A first communication apparatus 100 transmits a pilot signal which was generated by a pilot signal generation section 14, at predetermined timing, and detects an unbalance component of a transmission line 300 at the time of pilot signal transmission in an unbalance component detection section 13, and controls a transmission signal in such a manner that an unbalance component is reduced by a transmission control section 12 on the basis of the detected unbalance component.

Abstract: An electronic device capable of decreasing power consumption is provided. A multiple function apparatus including a power line communication function has a plurality of units such as a PLC board, a main control board, a printer control board, a printer, and a FAX control board. The multiple function apparatus also includes a device power supply unit for supplying power to the units independently. A power supply control unit of the PLC board outputs a power supply control signal in response to a state change of the multiple function apparatus and controls power supply to each unit.

Abstract: A line state detecting apparatus provided in a balanced transmission system includes, in transmission lines comprising a pair of conductors W1, W2 connected to a transmitting portion 13, current transformers T11, T12 primary 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 portion 11 for detecting currents or voltages on secondary sides of the current transformers T11, T12. By an output of the detecting portion 11, a difference of currents or voltages of the conductors W1, W2 of the transmission lines is provided and an unbalance component between the conductors W1, W2 is detected.

Abstract: A balanced transmission signal Tx (t) (voltage e, ?e) is applied to a transmission line (L1, L2), a suppression signal (ec) is generated from a common mode suppression signal source (ec), and the suppression signal (ec) is superposed on respectives of balanced transmission signals via adders (15a, 15b). By pertinently controlling a level of the suppression signal (ec), voltage levels and phases of respectives of the transmission signals transmitted to the transmission lines (L1, L2) are controlled.

Abstract: 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.

Abstract: An electronic device capable of decreasing power consumption is provided. A multiple function apparatus including a power line communication function has a plurality of units such as a PLC board, a main control board, a printer control board, a printer, and a FAX control board. The multiple function apparatus also includes a device power supply unit for supplying power to the units independently. A power supply control unit of the PLC board outputs a power supply control signal in response to a state change of the multiple function apparatus and controls power supply to each unit.

Abstract: 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.

Abstract: A cable connecting device for power line communication includes: a first wiring line 231 and a second wiring line 232 through which AC power is capable of being supplied; a power plug 120 which is electrically connected to the first wiring line 231 and the second wiring line 232 and whose wiring lines are capable of being supplied with AC power; an Ethernet port 110 through which a communication signal is capable of being input and output; a power line communication modem 220 that is connected to the Ethernet port 110 and that is connected to the second wiring line 232 through which a communication signal is transmitted by using AC power input to the power plug 120 through the first wiring line 231 between the power plug 120 and the Ethernet port 110; a filter 210 disposed on the first wiring line 231 and having high impedance in at least a frequency band used for power line communication rather than a frequency band used for AC power; and connectors 101 to 104 which axe electrically connected to the first wi

Abstract: 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.

Abstract: A first communication apparatus 100 transmits a pilot signal which was generated by a pilot signal generation section 14, at predetermined timing, and detects an unbalance component of a transmission line 300 at the time of pilot signal transmission in an unbalance component detection section 13, and controls a transmission signal in such a manner that an unbalance component is reduced by a transmission control section 12 on the basis of the detected unbalance component.

Abstract: A cable connecting device for power line communication includes: a first wiring line 231 and a second wiring line 232 through which AC power is capable of being supplied; a power plug 120 which is electrically connected to the first wiring line 231 and the second wiring line 232 and whose wiring lines are capable of being supplied with AC power; an Ethernet port 110 through which a communication signal is capable of being input and output; a power line communication modem 220 that is connected to the Ethernet port 110 and that is connected to the second wiring line 232 through which a communication signal is transmitted by using AC power input to the power plug 120 through the first wiring line 231 between the power plug 120 and the Ethernet port 110; a filter 210 disposed on the first wiring line 231 and having high impedance in at least a frequency band used for power line communication rather than a frequency band used for AC power; and connectors 101 to 104 which axe electrically connected to the first wi

Abstract: 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.

Abstract: A balanced transmission signal Tx (t) (voltage e, ?e) is applied to a transmission line (L1, L2), a suppression signal (ec) is generated from a common mode suppression signal source (ec), and the suppression signal (ec) is superposed on respectives of balanced transmission signals via adders (15a, 15b). By pertinently controlling a level of the suppression signal (ec), voltage levels and phases of respectives of the transmission signals transmitted to the transmission lines (L1, L2) are controlled.

Abstract: A line state detecting apparatus provided in a balanced transmission system includes, in transmission lines comprising a pair of conductors W1, W2 connected to a transmitting portion 13, current transformers T11, T12 primary 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 portion 11 for detecting currents or voltages on secondary sides of the current transformers T11, T12. By an output of the detecting portion 11, a difference of currents or voltages of the conductors W1, W2 of the transmission lines is provided and an unbalance component between the conductors W1, W2 is detected.

Abstract: 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.

Abstract: In a multicarrier communication using a balanced transmission line such as a power line, a multicarrier communication method operable to select carriers on the basis of an SN-ratio and balancing of the transmission line is provided. 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 of them, and the SN-ratio measured between the sending terminal and the receiving terminal. More specifically, any frequency domain having poor balancing and a poor SN-ratio is treated as a non-carrier-employing domain, and consequently the available carriers are selected at other frequency domains. In addition, a modulation method having the greatest permissible multivalue is selected for each of the carriers. The carriers are selected in light of the SN-ratio and balancing, or alternatively in highest-to-lowest order of frequency.