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: 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 unit 1 are converted into analog signals by an analog circuit unit 2 and then transmitted from a pair of lines 61 and 62 via a communication transformer 3. The digital signal-processing unit 1 has a frequency carrier detecting unit 10 which detects the existence of a carrier on the basis of a frequency characteristic of the received signal and the frequency carrier detecting unit 10 detects the carrier by taking correlation between sub-carriers adjacent to each other at every other interval.

Abstract: A communication apparatus includes a transmission signal generation section 1, a transmission signal control section 2, a transmission section 3, a leakage electric power detection section 4, and an electric power control judgment section 5. The transmission signal generation section 1 generates a transmission signal for carrying out transmission using a plurality of sub-carriers, under control of the transmission signal control section 2, and has a transmission electric power control function with respect to each sub-carrier. The leakage electric power detection section 4 detects electric power which is leaked from a transmission line 9 among transmission electric power.

Abstract: An OFDM signal generator performs inverse Fourier transform of frequency domain data of an OFDM signal, and generates and outputs time domain data. An output amplifier amplifies an analog signal transmitted via a delay unit and a D/A converter. Here, a comparator detects whether the amplitude of a signal has exceeded a predetermined value; and when the amplitude of the signal has exceeded the predetermined value, a timer outputs a timer output during a predetermined period. A voltage switcher switches a power voltage to be supplied to the output amplifier from low voltage power to high voltage power while a timer output is being generated; and increases the power voltage only during a predetermined period elapsed after the amplitude of a signal has exceeded a predetermined value.

Abstract: A power supply apparatus has a coupled transformer that inputs and outputs a communication signal and a capacitor that has high impedance to a commercial power supply frequency and low impedance to a communication signal frequency. The capacitor is connected between a primary winding of the coupled transformer and a power reception terminal. To both ends of the capacitor, a switching regulator is connected via a noise reduction circuit. To a secondary winding of the coupled transformer, a modem of a power line communication apparatus is connected. In the configuration, the coupled transformer and the switching regulator are thus connected in series.

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 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.

Abstract: A communication apparatus includes a transmission signal generation section 1, a transmission signal control section 2, a transmission section 3, a leakage electric power detection section 4, and an electric power control judgment section 5. The transmission signal generation section 1 generates a transmission signal for carrying out transmission using a plurality of sub-carriers, under control of the transmission signal control section 2, and has a transmission electric power control function with respect to each sub-carrier. The leakage electric power detection section 4 detects electric power which is leaked from a transmission line 9 among transmission electric power.

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 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 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: 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.

Abstract: The invention provides an information reading unit including a light emitting section for irradiating a light on an object, and a light receiving section for converting a light reflected from the object into an electric signal, wherein at least a part of the light receiving section has a light transmitting property, and the light receiving section and the light emitting section are laminated or the light receiving section and the light emitting section are provided on the same optical axis, and an information reading device wherein an electric signal obtained by the light receiving section is converted into a digital signal by using the information reading unit.