Abstract: A wireless apparatus is configured such that: a correlation calculation unit calculates a correlation coefficient for signals received from respective antennas; and a cyclic shift control unit compares the correlation coefficient with a threshold value. If the correlation coefficient is equal to or higher than the threshold value, the cyclic shift control unit determines that there is a direct wave, allocates a common shift amount to a cyclic shift unit, and causes a beam forming unit to form and transmit a narrow beam. Meanwhile, if the correlation coefficient is lower than the threshold value, the cyclic shift control unit determines that there is no direct wave, allocates different shift amounts to the cyclic shift unit, and causes the cyclic shift unit to diversify the cyclic shift.

Abstract: [Problem] To provide a wireless apparatus, a communication system, and a communication method that enable improvement in reliability by preventing disconnection of communication while enabling high-speed and long-distance transmission. [Solution] A wireless apparatus is configured such that: a correlation calculation unit 501 calculates a correlation coefficient for signals received from respective antennas 207; and a cyclic shift control unit 502 compares the correlation coefficient with a threshold value. If the correlation coefficient is equal to or higher than the threshold value, the cyclic shift control unit determines that there is a direct wave, allocates a common shift amount to a cyclic shift unit 202, and causes a beam forming unit 201 to form and transmit a narrow beam.

Abstract: A wireless communication system includes a transmitter that discretely inserts null subcarriers into an OFDM-demodulated signal in time and frequency domains, and a receiver that receive signals by a first and second antennas. The receiver calculates a complex coefficient wherein a result of multiplying a first reception vector for each of the null subcarriers received by the first antenna by the complex coefficient is equal to an amplitude of a second reception vector of the corresponding null subcarrier received by the second antenna and is opposite in phase thereto, calculates a fourth reception vector by multiplying a third reception vector of any data subcarrier received by the first antenna by a coefficient that is obtained by interpolating the complex coefficient, and adds the fourth reception vector to a fifth reception vector of the any data subcarrier received by the second antenna.

Abstract: A wireless communication system having a plurality of antennas is disclosed. A combination of transmission antennas and reception antennas is selected, the combination allowing ? to be the closest to ? radians, where ? represents an absolute value of an angle obtained by subtracting ?2 from ?1, where ?1 represents an angle formed by signal vectors transmitted from an i-th and a j-th transmission antennas of the first wireless device on an orthogonal plane on which a reception signal of a k-th reception antenna of the second wireless device is quadrature-detected or demodulated, and ?2 represents an angle formed by the signal vectors transmitted from the i-th and the j-th transmission antennas of the first wireless device on an orthogonal plane on which a reception signal of an l-th reception antenna of the second wireless device is quadrature-detected or demodulated.

Abstract: A wireless communication system includes a transmitter that discretely inserts null subcarriers into an OFDM-demodulated signal in time and frequency domains, and a receiver that receive signals by a first and second antennas. The receiver calculates a complex coefficient wherein a result of multiplying a first reception vector for each of the null subcarriers received by the first antenna by the complex coefficient is equal to an amplitude of a second reception vector of the corresponding null subcarrier received by the second antenna and is opposite in phase thereto, calculates a fourth reception vector by multiplying a third reception vector of any data subcarrier received by the first antenna by a coefficient that is obtained by interpolating the complex coefficient, and adds the fourth reception vector to a fifth reception vector of the any data subcarrier received by the second antenna.

Abstract: A wireless communication system having a plurality of antennas is disclosed. A combination of transmission antennas and reception antennas is selected, the combination allowing ? to be the closest to n radians, where ? represents an absolute value of an angle obtained by subtracting ?2 from ?1, where ?1 represents an angle formed by signal vectors transmitted from an i-th and a j-th transmission antennas of the first wireless device on an orthogonal plane on which a reception signal of a k-th reception antenna of the second wireless device is quadrature-detected or demodulated, and ?2 represents an angle formed by the signal vectors transmitted from the i-th and the j-th transmission antennas of the first wireless device on an orthogonal plane on which a reception signal of an l-th reception antenna of the second wireless device is quadrature-detected or demodulated.

Abstract: To effectively control the amplitude vs. power supply voltage characteristics, for example, in an ET amplifier.

Abstract: An efficient amplifying device is achieved. An amplifying device that amplifies a signal subject to amplification is configured as follows. That is, an amplifier (PA 5) that amplifies a signal is provided. Level control means 1 converts a level of the signal subject to amplification according to the level of this signal. Power supply control means 6 and 8 supply the amplifier (PA 5) with a power supply voltage determined according to the level of the signal subject to amplification. The amplifier (PA 5) amplifies a signal at the level converted by the level control means 1 with the power supply voltage supplied from the power supply control means 6 and 8.

Abstract: A display apparatus includes an LCD panel, a resin rear cabinet facing a back of the LCD panel, and a backlight unit that is supported by the rear cabinet. The backlight unit includes a light source, a light guide plate into which light from the light source enters through a side surface and exits through a main surface toward the back of the LCD panel, and a heat sink supported by the rear cabinet and attached to the light source. The rear cabinet includes an integrally formed resin protrusion passing through the heat sink and supporting the light guide plate, and positioning of the light source is determined by a contact surface thereof with the heat sink and positioning of the light guide plate is determined by a contact surface thereof with the protrusion so that optical axes of the light source and the light guide plate are aligned.

Abstract: A display device includes a display portion displaying an image on the front side, a light guide plate arranged on the rear side of the display portion, a heat radiation member arranged on the rear side of the light guide plate, radiating the heat of the light source, and a reflective sheet arranged between the light guide plate and the heat radiation member, including a heat reflecting portion capable of reflecting the heat radiated from the heat radiation member to the heat radiation member on the rear side, while the heat radiation member includes a heat releasing portion configured to release the heat reflected by the heat reflecting portion to the rear side of the heat radiation member.

Abstract: To effectively control the amplitude vs. power supply voltage characteristics, for example, in an ET amplifier.

Abstract: An efficient amplifying device is achieved. An amplifying device that amplifies a signal subject to amplification is configured as follows. That is, an amplifier (PA 5) that amplifies a signal is provided. Level control means 1 converts a level of the signal subject to amplification according to the level of this signal. Power supply control means 6 and 8 supply the amplifier (PA 5) with a power supply voltage determined according to the level of the signal subject to amplification. The amplifier (PA 5) amplifies a signal at the level converted by the level control means 1 with the power supply voltage supplied from the power supply control means 6 and 8.

Abstract: A distortion compensation amplification device includes a level detecting means that detects a signal level, a correspondence storage means that outputs a distortion compensation coefficient depending on the signal level, a pre-distortion executing means that gives distortion with an inverse characteristic to the signal, a filtering means that outputs a distortion component from a feedback signal output from an amplifier, and a correspondence acquiring means that updates a learning coefficient constituting a function that gives the inverse characteristic so as to reduce the distortion component. Each orthogonal function is the total sum of products of functions of the input signal and parameters. The parameter values are set to cause the orthogonal functions to be orthogonal to each other when functions are replaced for the functions of the input signal constituting the orthogonal functions.

Abstract: A power circuit used for an amplifier, which includes an amplifier provided with a linear amplifier serving as a voltage source, a DC/DC converter serving as a current source, a hysteresis comparator controlling the DC/DC converter, and a current detector detecting output current from the linear amplifier to output the detected output current to the hysteresis comparator; and a switching restricting device for restricting a switching interval in the DC/DC converter such that the switching interval is not equal to or less than a constant time or is not shorter than the constant time.

Abstract: The present invention provides a non-linear distortion detection method and a distortion compensation amplifying device capable of suppressing increase of the circuit size and the power consumption even if the signal band is widened. A signal obtained by feeding back an output of a power amplifier is sampled by an A/D converter. An equalizer of a distortion detection unit uses an input signal d(n) of a predistorter as a reference symbol to detect an equalization error e(n) of the orthogonal demodulation signal u(n). An absolute value averaging unit outputs an absolute value of the equalization error e(n) which has been temporally averaged to E(n) as a distortion value to a control unit. According to the distortion value, the control unit adaptively controls the predistorter to perform distortion compensation.

Abstract: It is intended to increase the efficiency of a distortion compensation amplification device having a pre-distorter 1. Level detecting means 11 detects a signal level, correspondence storage means 12 outputs a distortion compensation coefficient depending on the signal level, pre-distortion executing means 13 gives distortion with an inverse characteristic to the signal, filtering means 8 outputs a distortion component from a feedback signal output from an amplifier 4, and correspondence acquiring means 14 updates a learning coefficient constituting a function that gives the inverse characteristic so as to reduce the distortion component. The function that gives the inverse characteristic is expressed using a set of orthogonal polynomials.

Abstract: The invention aims to converge predistortion coefficients efficiently in a predistorter adapted to compensate for distortion generated in an amplifier. Level detection means detects the level of a signal input to an amplifier. Signal acquisition means acquire a signal output from the amplifier as a feedback signal. Correspondence acquisition means updates a predistortion coefficient expressed using a set of orthogonal polynomials so that a distortion component contained in the acquired feedback signal is reduced and acquires a correspondence between the level of the signal input to the amplifier and a control coefficient for predistortion (contents of a distortion compensation table). Predistortion executing means applies distortion for predistortion with respect to the signal input to the amplifier in accordance with the control coefficient for predistortion that corresponds to the detected level based on the acquired correspondence.

Abstract: A power circuit used for an amplifier, which includes an amplifier provided with a linear amplifier serving as a voltage source, a DC/DC converter serving as a current source, a hysteresis comparator controlling the DC/DC converter, and a current detector detecting output current from the linear amplifier to output the detected output current to the hysteresis comparator; and a switching restricting means for restricting a switching interval in the DC/DC converter such that the switching interval is not equal to or less than a constant time or is not shorter than the constant time.

Abstract: An amplifying apparatus includes a splitting unit for splitting an input signal into a first split signal and a second split signal; phase-shifting unit for phase-shifting the first split signal and the second split signal, respectively; a first amplifying unit for amplifying a first phase-shifted signal and outputting the signal as a first output signal; a second amplifying unit for amplifying, in a substantially identical manner to the first amplifying unit, a second phase-shifted signal and outputting the signal as a second output signal; and a matching unit for matching the first output signal and the second output signal to a first transmission unit and a second transmission unit, respectively. The first transmission unit is for transmitting the first output signal from the matching unit to a load resistor, and the second transmission unit is for transmitting the second output signal from the matching unit to the load resistor.

Abstract: The invention provides a spectrum analyzing method, a distortion detector and a distortion compensation amplifying device for performing time/frequency conversion processing at high speed, and reducing a convergent time of a compensation coefficient. The distortion detector for detecting distortion in a frequency area with respect to an input signal includes a time window processing section for multiplying the input signal by a time window; an averaging processing section for averaging an output of the time window processing section; an FFT processing section for converting an output of the averaging processing section from a time area to a frequency area; and a distortion extracting section for extracting a distortion component from an output of the FFT processing section.