Fujitsu Corporation

Yousuke Okazaki

Hiroaki Maeda

Yoshinobu Shizawa

Hirotake Honda

Takashi Ono

Hiroyuki Ogawa

Junya Morita

Satoshi Matsubara

Yasushi Seino

Yasuhiro Okawa

Hiroyuki Ezuka

Akira Seino

A distortion compensation apparatus including: an amplifier configured to amplify an input signal including a transmission signal and an impulse signal, the transmission signal being converted to a radio frequency signal for transmission, the impulse signal being not converted to a radio signal for transmission, a memory configured to store a plurality of distortion compensation coefficients for compensating distortion to the input signal, each of the plurality of distortion compensation coefficients being associated with an amplitude of the input signal, and a processor configured to select a distortion compensation coefficient from the plurality of distortion compensation coefficients based on an amplitude of the impulse signal included in the input signal, and update the selected distortion compensation coefficient based on the amplified impulse signal include in the amplified input signal.

Distortion compensation apparatus, wireless communication system, and distortion compensation method

A wireless device includes a digital-to-analog converter that converts a digital transmission signal within a digital signal processing band to an analog transmission signal, a modulator that performs quadrature modulation of an analog transmission signal obtained by the digital-to-analog converter using a first local signal having a first frequency outside a frequency range, the frequency range centered around a center frequency of a transmission signal and having a bandwidth of the digital signal processing band, and outputs a modulated signal, a frequency converter that performs a frequency shift of a modulated signal output from the modulator using a second local signal having a second frequency within the frequency range, and an inhibitor that performs carrier leakage inhibition processing on the digital transmission signal, based on a signal obtained by the frequency converter.

Wireless device and wireless access system

A wireless communication apparatus includes: a first amplifier configured to amplify an input signal; a second amplifier configured to amplify the input signal when an input level of the input signal is equal to or larger than a given level; an impedance converter configure to switch an load impedance of the first amplifier and output a composite output of an output from the first amplifier and an output from the second amplifier; an impedance controller section configured to control a switching of the load impedance of the first amplifier based on a bandwidth of the input signal; a distortion compensation section configured to perform distortion compensation of the input signal and supply a compensated input signal to the first amplifier and the second amplifier; and a filter section configured to limit a band of a signal output from the impedance converter.

Wireless communication apparatus, Doherty amplifier, and method for controlling wireless communication

A power amplifying apparatus has a GaN device for RF amplification, a GaN device for monitoring, an Idq detecting circuit, and a gate bias control (GBC) circuit. The GaN device for RF amplification amplifies an input signal to output the resultant. The GaN device for monitoring is an amplification device for monitoring an input/output signal of the GaN device for RF amplification. The Idq detecting circuit detects an output signal output by the GaN device for monitoring, corresponding to an input signal, which is diverged from the input signal to be input to the GaN device for RF amplification, and is input to the GaN device for monitoring. The gate bias control circuit controls a gate voltage to be applied to the GaN device for RF amplification in accordance with the output signal detected by the Idq detecting circuit.

Amplifying apparatus, transmitter, and amplifying apparatus control method

An amplifying apparatus includes a first amplifier that amplifies an input signal on the basis of a value of a drain voltage and outputs a transmission signal, a distortion compensator that corrects a power amplitude of the input signal on the basis of a difference in power amplitude between the input signal and the transmission signal outputted from the first amplifier, a drain voltage controller that generates the drain voltage on the basis of the power amplitude of the input signal to be corrected, and a drain voltage corrector that corrects the drain voltage on the basis of the difference.

Amplifying apparatus

An amplifying device includes an amplifier including a first amplifying element with a drain voltage thereof being controlled, and a second amplifying element, the amplifier amplifying a transmission signal with the first and second amplifying elements, synthesizing the transmission signals amplified by the first and second amplifying elements, and outputting the synthesized transmission signal; a distortion compensator part which performs distortion compensation on the input signal in accordance with a compensation coefficient derived from a difference between a input signal and a feedback signal generated from a portion of a signal output from the amplifier; and a controller part which controls the drain voltage of the first amplifying element in response to a result of a comparison between a power level of the input signal prior to the distortion compensation operation by the distortion compensator part and a threshold value.

Amplifying device and transmitter apparatus

An amplifier failure detection apparatus for a radio transmitter that has a function for compensating for amplifier distortion of the radio transmitter and a function for determining amplifier failure has occurred by detecting that the gain of an amplifier has dropped a set level or more, in which: a gain-detection unit detects the gain of the amplifier; an alarm-detection-level-generation unit, which has a table for storing alarm-detection levels that correspond to input-amplitude levels, generates an alarm-detection level that corresponds to an input-amplitude level; and a comparison unit compares the gain detected by the gain-detection unit with the alarm-detection level, and generates an alarm based on the comparison results.

Amplifier failure detection apparatus

The amplifying apparatus includes an amplifier having a circuit constant determined so as to satisfy a condition for E-class operation; power detecting unit which detects an output electricity from the amplifier; and controlling unit which controls the circuit constant in accordance with the output power detected by the power detecting unit.

The present invention provides an amplifier unit including a carrier amplifier biased for Class A or Class AB operation; a peak amplifier biased for Class B or Class C operation, wherein an input signal is input to the carrier amplifier and the peak amplifier, and wherein output signals from the carrier amplifier and the peak amplifier are synthesized to output therefrom; a comparator configured to compare a gate bias voltage of a transistor device in the peak amplifier with a predetermined threshold voltage and output a first output signal; and a failure detection circuit configured to output a second output signal indicating presence or absence of failure, based on the first output signal received from the comparator.

Amplifier unit and method of detecting failure in the same

To cancel a reflected wave reflected from a connecting portion () and leaking into a feedback signal when a non-matched component is connected, the reflected wave is extracted by a circulator () and its phase and amplitude are adjusted by a vector adjusting circuit (), and then the thus adjusted reflected wave is vector-summed with the feedback signal in a vector sum circuit ().

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Kawasaki, Japan

Yousuke Okazaki