Abstract: A radio communication device includes a power amplifier to amplify a transmit signal, a control unit to generate a voltage control signal for defining power to be supplied to the power amplifier in accordance with a conversion curve expressed using a polynomial series based on an envelope signal obtained from the transmit signal and determine the polynomial series based on an efficiency of the power amplifier, and a power source unit to supply the power to the power amplifier based on the voltage control signal, wherein the control unit divides an amplitude range of the envelope signal on the conversion curve into a plurality of sections and determines the polynomial series based on at least one of the plurality of sections.

Abstract: A distortion compensation device includes a distortion compensator that predistorts an input signal based on delay signals and distortion compensation coefficients corresponding to the respective delay signals obtained by applying different amounts of delay to the input signal, a calculator that calculates an error signal based on the predistorted input signal and an output signal from an amplifier that amplifies the predistorted input signal, a calculator that calculates prospective distortion compensation coefficients for updating the distortion compensation coefficients, based on the error signal, a saturation processor that performs saturation processing for bringing, when the prospective distortion compensation coefficients do not fall into a preset range, the prospective distortion compensation coefficients into the preset range, and a controller that controls the updating of the distortion compensation coefficients based on pieces of coefficient saturation information indicating whether the saturation

Abstract: A power amplifier apparatus that includes a processor that performs a first distortion compensation processing on an input signal using a distortion compensation coefficient to obtain a first signal and an amplifier that amplifies the first signal. The processor performs a second distortion compensation processing the amplified signal using the distortion compensation coefficient to obtain a second signal and updates the distortion compensation coefficient to enable convergence between the first signal and the second signal.

Abstract: A power amplifying apparatus includes a high-speed low pass filter which inputs an envelope signal included in a transmission signal therein, a low-speed low pass filter which inputs the envelope signal therein, a determination unit which inputs the envelope signal therein and determines rising or falling of the envelope signal, a selecting unit which selects one of the high-speed low pass filter and the low-speed low pass filter according to a determined result of the determination unit, and a voltage supply unit which generates a voltage based on a signal input according to a selection by the selecting unit and supplies the voltage to a power amplifier which inputs the transmission signal therein so as to amplify a power of the transmission signal.

Abstract: A transmission apparatus includes an analog digital converter that performs sampling on a demodulated signal obtained by demodulating a part of an output signal, which is produced by amplifying a modulated signal of a baseband signal including a plurality of signals having frequencies separated from each other, at a sampling frequency lower than a frequency of a given intermodulation distortion component and converting the demodulated signal into a digital signal, a detection section that detects an aliasing component of the given intermodulation distortion component produced by the conversion of the analog digital converter, and a distortion compensation section that compensates an input signal to be modulated for the given intermodulation distortion component in accordance with the detected aliasing component.

Abstract: A peak suppressing apparatus includes an amplitude limiter that limits amplitude of the transmission signal with a predetermined threshold; a peak-suppressing-signal extracting unit that extracts a peak suppressing signal by subtracting the transmission signal before the amplitude limiting from the transmission signal amplitude-limited by the amplitude limiter; a filtering unit that performs filtering so that a frequency characteristic of the peak suppressing signal extracted by the peak-suppressing-signal extracting unit becomes flat; and an adder that adds the peak suppressing signal filtered by the filtering unit to the transmission signal.

Abstract: A peak suppression threshold value control unit receives an input of quality requirement information, such as a modulation system and coding ratio, from a baseband signal generation unit, determines a threshold value of a peak suppression unit based on the quality requirement information and outputs the threshold value to a peak suppression unit. The peak suppression unit applies a peak suppression control to a baseband signal input from a baseband signal generation unit based on the threshold value and outputs a signal (i.e., a peak suppression signal) applied by the peak suppression process.

Abstract: In a configuration where systems C and D having different reception quality requirements are present, a peak suppressor generates a replica of a signal from system C combined together with a signal from system D before peak suppression. Based on the replica, system specific peak suppressing units respectively perform peak suppression on signals of each system according to the respective reception quality requirements of each system. A combining unit combines the peak-suppressed signals of each system. Hence, peak suppression on signals from systems requiring different reception qualities is performed at an appropriate degree according to each system.

Abstract: A distortion compensation device includes a distortion compensation unit which compensates for a distortion generated in a power amplifier by using a polynomial in which a signal to be input into a power amplifier is raised to a power of a degree N (N is an integer larger than 0) and the raised signal is delayed by a delay number K (K is an integer larger than 0), and a polynomial adjusting unit which adjusts the degree N or the delay number K of the polynomial based on a comparison between a prescribed value, which indicates a degree of variation of the distortion generated in the power amplifier and a threshold value.

Abstract: A peak suppressing and restoring method includes suppressing a peak of a signal, starting suppression when a suppression start value is lower than a suppression target value, using a function of a gain characteristic such that a peak amplitude value attains the suppression target value, and restoring the suppressed peak of the signal using an inverse function of the function of the gain characteristic.

Abstract: An apparatus includes: a unit that stores the look-up table including distortion compensation coefficients; a unit that selects addresses according to an input signal, acquires coefficients stored at the selected addresses, and performs the predistortion of the input signal by using the acquired coefficients; a unit that calculates an error signal by comparing with the input signal a feedback signal that indicates an output of a power amplifier to which a result of the predistortion is inputted; a unit that calculates coefficients from the error signal and the acquired coefficients by using the adaptive algorithm; a unit that, for each of the selected addresses, selects coefficients as adequate coefficients from among the calculated coefficients according to the error signal; and a unit that, for each of the selected addresses, calculates an average value of the adequate coefficients and replaces a stored coefficient in the look-up table with the average value.

Abstract: A distortion compensation apparatus includes a distortion compensation unit that performs distortion compensation processing on a transmission signal by a series operation, a coefficient update unit that updates a group of series operation coefficients used for the series operation based on a feedback signal of transmission signal output that is output after power amplification processing is performed on output of the distortion compensation unit and the transmission signal, an initial coefficient memory that stores the groups of series operation coefficients that become initial values for coefficient update processing by the coefficient update unit, and a power fluctuation detection unit that detects a power fluctuation of the transmission signal and, when the power fluctuation is detected, reads the groups of series operation coefficients from the initial coefficient memory and provides the groups of series operation coefficients to the coefficient update unit.

Abstract: A bias control signal generation unit detects ON and OFF of a transmission signal input to an amplifier and having a property of a burst according to burst information. The bias control signal generation unit controls a bias voltage to be applied to an amplifier such that an idle current flowing through the amplifier can be flowing in a larger amount in a transmission OFF period, and can return to a normal level in a transmission ON period.

Abstract: A technique wherein when signals, the modulation schemes of which are different, are to be combined, performing the peak suppression using amounts of the respective modulation schemes can effectively reduce the PAPR of a resulting combined signal. A peak suppressing method for use in a peak suppressing circuit, which combines input signals of different modulation schemes in a time domain to provide a combined signal, comprises detecting, as a peak, that portion of the combined signal which excesses a threshold value to generate a peak signal in accordance with the peak; converting the peak signal into a frequency domain signal and then dividing it into signals originating from the input signals to use these input-signal-originated signals as respective suppression signals; and adding, to the input signals, the suppression signals having different suppression amounts for the respective modulation schemes, thereby performing the peak suppression.

Abstract: A predistortion apparatus for compensating for a distortion arising from a non linear property in input to output characteristics of an amplifier, by processing calculation of a plurality of coefficients for a plurality of power series defining the predistortion characteristics for a plurality of power ranges, respectively, the predistortion apparatus includes: a coefficient update unit for setting and updating coefficients of the power series to provide the predistortion characteristics for the plurality of power ranges in accordance with a comparison between the input and output of the amplifier; and a determination unit for determining at least one threshold value defining the plurality of power ranges by shifting the threshold value and operating the coefficient update unit for updating the coefficients for each of the power series corresponding to each of the power ranges defined by the shifted threshold value.

Abstract: A disclosed transmission device includes a voltage control signal generating unit configured to generate a first voltage control signal from a transmission signal, an amplifier configured to amplify the transmission signal in response to the first voltage control signal, a first timing adjusting unit configured to adjust a control timing for the first voltage control signal, and a control timing setting unit configured to set the control timing adjusted by the first timing adjusting unit based on the output signal from the amplifier and the transmission signal.

Abstract: A radio communication device includes a power amplifier to amplify a transmit signal, a control unit to generate a voltage control signal for defining power to be supplied to the power amplifier in accordance with a conversion curve expressed using a polynomial series based on an envelope signal obtained from the transmit signal and determine the polynomial series based on an efficiency of the power amplifier, and a power source unit to supply the power to the power amplifier based on the voltage control signal, wherein the control unit divides an amplitude range of the envelope signal on the conversion curve into a plurality of sections and determines the polynomial series based on at least one of the plurality of sections.

Abstract: A wireless apparatus includes: an A/D converter which samples an in-phase signal component and a quadrature signal component from a quadrature-modulated signal of analog form alternately; a digital quadrature demodulation unit which applies digital quadrature demodulation to an output signal of the A/D converter and outputs an in-phase signal and a quadrature signal; and an error detection unit which, based on the in-phase and quadrature signals output from the digital quadrature demodulation unit, detects a time difference error between the sample timing of the in-phase signal component and the sample timing of the quadrature signal component.

Abstract: A distortion correction control apparatus is for compensating for a burst distortion of a transmission amplifier caused by a burst of an input signal of a transmission target. The apparatus includes a generation unit that generates a distortion correction coefficient having reverse characteristics to the foregoing burst distortion; a unit that multiplies the distortion correction coefficient output from the generation unit by the input signal or adds the distortion correction coefficient output from the generation unit to the input signal, upon reception of burst information notifying of switching between presence and absence of the input signal; and an update unit that updates, based on the input signal and a branch signal fed back as an output signal of the transmission amplifier, parameters of functions used for adaptively generating the distortion correction coefficient, and that inputs the updated parameters to the generation unit.

Abstract: A distortion compensating apparatus has an adaptive distortion compensating unit to compensate nonlinear distortion by controlling an input signal of a nonlinear distortion circuit by using an adaptive algorithm so as to reduce an error between a reference signal and a feedback signal from the nonlinear distortion circuit; and an adaptive equalizer connected between the adaptive distortion compensating unit and the nonlinear distortion circuit or provided in front of the adaptive distortion compensating unit. The adaptive equalizer includes a digital filter to form an amplitude characteristic and a phase characteristic of the input signal on the basis of a filter coefficient group that is set to the digital filter; a memory to hold in advance the filter coefficient group; and a control unit to control reading of the filter coefficient group from the memory on the basis of the input signal and the feedback signal.