Hitachi-kokusai Electric Inc.

Junya Dosaka

Yoichi Okubo

Taizo Ito

Toshio Nojima

Manabu Nakamura

Yasuhiro Takeda

Junichiro Yamakawa

Taizo Yamawaki

Naoki Hongo

Takashi Kawamoto

Akira Maeki

Kiyoshi Funada

Yasuo Sera

Terufumi Nagano

Hidekatsu Ueno

Osamu Sato

Hideyuki Yanagiya

Ryoki Haramoto

A wireless communication device configured to prevent a transmission time period for sending a wireless signal and a receiving time period for receiving a wireless signal from being overlap, comprises: a transmitter that includes an orthogonal modulator that orthogonally modulates an IQ-modulated modulation signal and a transmission power amplifier that power-amplifies the orthogonally modulated signal; a receiver that includes a demodulator that demodulates a received signal; a first power source that is the power source for the transmission power amplifier and the receiver; and a second power source that is the power source for the orthogonal modulator; and a controller which outputs the modulation signal to the orthogonal modulator. The first power source outputs a constant voltage to the receiver during the receiving time period, and outputs, during the transmission time period, to the transmission power amplifier, a fluctuating voltage according to an envelope of the modulation signal.

Wireless communication device and power source device

Provided is a technique for effectively implementing DC removal during switching of transmission scheme or transmission data in a wireless apparatus equipped with a function for supplying a voltage to a power amplifier by ET control. When the ET control is not carried out in a power supply unit, more specifically, when an IQ signal is not present, a control unit outputs a pulse width modulation (PWM) signal for a fixed voltage via a switch unit. In other words, the switch unit selectively supplies a PWM signal for ET and a PWM signal for the fixed voltage to a switching amplifier. The switching amplifier is controlled by a predetermined control signal from the control unit.

Wireless apparatus and method for controlling voltage supplied to amplifier unit

A wireless communications device for performing wireless communications includes a notifying unit for notifying a user of a status of the corresponding wireless communications device when a dedicated user interface is manipulated, a display unit and a detector for detecting failure in the display unit. The notifying unit notifies the user of the status of the corresponding wireless communications device when a failure in the display unit is detected by the detector and prevents the status of the corresponding wireless communications device from being notified when the failure in the display unit is not detected by the detector.

Wireless communications device

An amplifier capable of lowering an electrical current flowing in a peak amplifier before a carrier amplifier becomes saturated to thereby improve the efficiency of an entirety of the amplifier is provided. The amplifier includes a carrier amplifier circuit having an amplifying element operable in class-AB or class-B, and a plurality of peak amplifier circuits which have amplifying elements operating in class-B or class-C and which are arranged to start an operation in stages in response to an input level. An output of the carrier amplifier circuit and outputs of the peak amplifier circuits are combined together for signal output. One of the peak amplifier circuits which is rendered operative at the lowest input level is smaller in saturation output than the carrier amplifier circuit.

Amplifier apparatus

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.

Power circuit used for an amplifier

A distortion compensation apparatus includes distortion generating means for generating distortions to compensate for a distortion generated in an amplifier. The distortion generating means includes a nonlinear circuithaving an input/output expansion characteristic as a circuit which generates a distortion of the lowest odd order as a compensation target and also includes a nonlinear circuithaving an input/output saturation characteristic as a circuit which generates a distortion of another odd order as a compensation target.

Distortion compensation apparatus

An amplification apparatus that has a distortion detection loop that detects distortion components contained in an amplified signal to be amplified that is amplified by an amplifier, and a distortion removal loop that removes distortion components from the amplified signal, using the distortion components detected by the distortion detection loop, combines a reference signal (pilot signal) with the signal to be amplified, and performs control relating to distortion compensation, using said reference signal, to provide improved efficiency with respect to a configuration to perform control relating to distortion compensation, using a reference signal. A signal to be amplified is detected by amplification signal detection meansand, and when it is detected by the amplification signal detection means that there is no input of a signal to be amplified, reference signal control meansperform control to effect non-output of the reference signals.

Amplification apparatus

A transmission amplifier for amplifying a signal to be transmitted includes an amplifying unit that is warmed efficiently when the temperature is low. In a constitution in which an amplifying unit amplifies a signal, a temperature detecting means detects temperature. Amplifying-unit-self-heating-facilitation control means perform control for facilitating self-heating by the amplifying unit when temperature detected by the temperature detecting means is lower than a predetermined threshold value, or equal to or lower than the predetermined threshold value. The amplifying-unit-self-heating-facilitation control means perform, for example, bias control for the amplifying unit as the control for facilitating self-heating by the amplifying unit.

Transmission amplifier

Excellent compensation of the distortion is realized with a distortion-compensated amplifier device that compensates a distortion that is generated in a main amplifier, through the respective operations of a circuit comprised of a distortion-detecting loop and a distortion-compensating loop and a pre-distortor. In a distortion-detecting loop, the signal is distributed. With respect to one distribution signal, a vector adjuster ( ) performs vector adjustment of it and the pre-distortor ( ) generates a distortion. A main amplifier ( ) amplifies this signal. The resulting amplification signal and the other distribution are composed, whereby a distortion component is detected. In a distortion-compensating loop, that amplification signal and this distortion component are composed to thereby eliminate the distortion component from the amplification signal. In a control part, a distortion component level detecting means ( ) detects the levels of the distortion component that is detected. Vector adjusting/controlling means ( ) and ( ) controls the vector adjusting means ( ) to thereby make the average value of those levels small. On the other hand, pre-distortor controlling means ( ) and ( ) controls the pre-distortor ( ) to thereby make the peak values of those levels.

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Tokyo, Japan

Junya Dosaka