Abstract: A multicarrier signal transmission apparatus provided with a hard clip suppression unit for hard clipping a peak part of a multicarrier signal, a low pass filter for filtering the signal hard clipped by the hard clip suppression unit, and a peak suppression unit for suppressing the peak part of the signal after filtering by the low pass filter, the peak suppression unit provided with a peak detection unit for detecting a peak part of the filtered signal, a window function generation unit for generating a window function of an amplitude in accordance with a peak level of the peak part, and a peak suppressor for attenuating the peak part in accordance with the value of the window function.

Abstract: A timing controller is disclosed that includes: an amplifier part configured to amplify a first input signal in accordance with a control voltage, the first input signal being one of a transmission signal and a signal of a fixed value; a detector part configured to detect envelope information from the output signal of the amplifier part; a controller part configured to determine a delay difference from the transmission signal and the envelope information and transmit a timing control signal based on the delay difference; and a delay corrector part configured to correct the delay of a second input signal in accordance with the timing control signal, the second input signal being one of the transmission signal and a signal of a fixed value. One of the first and second input signals employs the corresponding signal of the fixed value in the case of correcting the delay.

Abstract: A timing adjusting method detects a phase error between a main signal path from which a transmitting signal is obtained and a control signal path from which a voltage control signal is obtained, based on a to-be-amplified signal that is to be amplified and represents an amplitude or a power of the transmitting signal prior to amplification and a feedback signal that represents an amplitude or a power of the transmitting signal after the amplification, adjusts an amount of delay of at least one of the main signal path and the control signal path so as to mutually cancel the phase error, and amplifies the transmitting signal from the main signal path depending on the voltage control signal from the control signal path. The detecting the phase error may include detecting polarity transition points of a slope of a waveform of the to-be-amplified signal or the feedback signal, and measuring the phase error using the detected polarity transition points.

Abstract: A device is disclosed that includes an amplification part for a linear transmitter, the amplification part being configured to amplify a transmission signal in accordance with a supply voltage control signal; a generation part configured to generate a power supply signal showing the level of the transmission signal; and a control part configured to output the supply voltage control signal based on the power supply signal. The control part includes a storage part configured to store a series of values of the power supply signal belonging to a time range including a certain point of time; and an output part configured to output a maximum one of a predetermined number of values of the series of values of the power supply signal as the supply voltage control signal at the certain point of time.

Abstract: In an electronic device having a circuit outputting a vector sum of two quadrature vector signals, an offset compensating device compensates the offset contained in the vector sum. The offset compensating device aims to flexibly adapt to deviation in characteristics and performances and various fluctuations, and to compensate offset stably and accurately. The offset compensating device includes a deviation monitor unit creating a vector signal by A/D-converting the aforementioned vector sum and by quadrature-demodulating it and monitoring the deviation of the DC components superposed on the vector signal, and an adaptive control unit updating the compensation vector determined in advance, based on adaptive algorithm minimizing expectation value of the product of the inner product between an increment vector and the compensation vector, and the latest deviation vector, and adding the compensation vector to an offset vector to be inputted, while being superposed on the input signal, to a circuit.

Abstract: The distortion compensator which compensates the nonlinearity of a power amplifier in a radio communication device stops the operation of updating the automatic phase adjustment, automatic delay adjustment, equalizer adjustment, and distortion compensation table when something wrong is detected in the input to a distortion compensation unit such as a reference signal, feedback signal, address of the distortion compensation table, and phase value so that the distortion compensation coefficients may not be improperly updated.

Abstract: Disclosed is a phase calibration method for inserting a calibration signal (SC) into main signals (SM1 to SMn) of a plurality of branches in turn, estimating the phase characteristic of an analog circuit to which a respective one of the main signals is input and calibrating the phase of each main signal. The method includes steps of outputting a first combined signal obtained by combining output signals from the analog circuits (62a to 62n) in all branches, outputting a second combined signal obtained by combining the main signals in all branches, extracting the calibration signal by removing the second combined signal from the first combined signal in a calibration signal extracting unit (64), estimating the phase characteristics of the analog circuits, to which the main signals having the inserted calibration signal are input, based upon a change in phase of the calibration signal, and subjecting the main signals to phase adjustment having characteristics that are opposite the phase characteristics.

Abstract: A wireless communication system, to control a peak power to an average power ratio because an amplifier characteristic of the wireless communication system include non-linear characteristic if input signal large the amplifier makes distortions. A wireless communication system comprises for suppressing a peak power to an average power ratio to process known signal like a pilot signal.

Abstract: A multicarrier signal transmission apparatus able to adjust the balance between the quality of reception and generation of an out-band spurious wave by a simple configuration, comprising a peak detector for detecting a peak part of a transmitted multicarrier signal, a window function generator for generating a window function of an amplitude in accordance with a peak level of a detected peak part, and a peak suppressor for attenuating the peak part in accordance with the value of the generated window function, and a multicarrier signal receiving apparatus, multicarrier signal transmission method, multicarrier signal receiving method, and communication system used with the same.

Abstract: The present invention provides a transmission device for predistorting a digital signal in order to compensate distortion, then amplifying and transmitting it. A digital input signal is converted to a first analog signal by a first D/A converter. Separately, the digital input signal is also subjected to predistortion. A compensating signal is then generated from the digital input signal and the predistorted signal. The compensating signal generated thereby is converted into a second analog signal by a second D/A converter. The first analog signal and second analog signal are then added, this addition operation giving a compensated analog transmission signal. This analog transmission signal is supplied to the amplifier for amplification, and then transmitted via an antenna.

Abstract: A disclosed quadrature modulation system inputs an inphase signal component and an orthogonal signal component, and outputs an output signal that is quadrature modulated by a quadrature modulator. The quadrature modulation system calculates a first cumulative total based on the inphase signal component input into the quadrature modulator and an inphase signal component of a feedback signal obtained from the output signal. The quadrature modulation system calculates a second cumulative total based on the orthogonal signal component input into the quadrature modulator and an orthogonal signal component of the feedback signal. Based on the first and the second cumulative totals, a time difference between the inphase signal component and the orthogonal signal component is determined. The inphase signal component and the orthogonal signal component to be provided to the quadrature modulator are adjusted based on the time difference such that the time difference is compensated for.

Abstract: In an array-antenna-equipped communication apparatus, a part of a transmission signal after passing through a radio wave transmitter is branched by a directional coupler, combined by a combiner, converted to a baseband signal by a receiver for calibration, analog-converted by an analog-to-digital converter, and input to an adaptive controller as a feedback signal. The adaptive controller calculates a calibration value that minimizes the power of an error signal representing a difference between the feedback signal and a reference signal, which is the transmission signal before passing through the radio wave transmitter, and outputs the calibration value to a corrector for calibration.

Abstract: Disclosed is a phase calibration method for inserting a calibration signal (SC) into main signals (SM1 to SMn) of a plurality of branches in turn, estimating the phase characteristic of an analog circuit to which a respective one of the main signals is input and calibrating the phase of each main signal. The method includes steps of outputting a first combined signal obtained by combining output signals from the analog circuits (62a to 62n) in all branches, outputting a second combined signal obtained by combining the main signals in all branches, extracting the calibration signal by removing the second combined signal from the first combined signal in a calibration signal extracting unit (64), estimating the phase characteristics of the analog circuits, to which the main signals having the inserted calibration signal are input, based upon a change in phase of the calibration signal, and subjecting the main signals to phase adjustment having characteristics that are opposite the phase characteristics.

Abstract: A distortion compensation apparatus of the present invention is used in a transmitter that produces and outputs a second signal from a first signal. This apparatus comprises a delay unit for delaying a feedback signal obtained from by the second signal; and a delay control unit for determining a delay quantity of said delay means so that a timing difference between a reference signal obtained from the first signal and the feedback signal delayed by the delay unit is made small. The delay control unit limits the delay quantity within a predetermined limit value.

Abstract: The distortion compensator which compensates the nonlinearity of a power amplifier in a radio communication device stops the operation of updating the automatic phase adjustment, automatic delay adjustment, equalizer adjustment, and distortion compensation table when something wrong is detected in the input to a distortion compensation unit such as a reference signal, feedback signal, address of the distortion compensation table, and phase value so that the distortion compensation coefficients may not be improperly updated.

Abstract: Disclosed is an adaptive control apparatus having an error calculation unit for calculating the difference between a reference signal and a feedback signal, and an adaptive controller for applying adaptive control so as to diminish the difference and causing the result of adaptive control to be reflected in the reference signal. The adaptive control apparatus has a delay unit for delaying at least one of the reference signal and feedback signal by a set delay time in such a manner that the reference signal and feedback signal will be input simultaneously to the arithmetic unit; a frequency-component detecting unit for detecting a frequency component of the reference signal; a delay-time acquisition unit for acquiring delay time conforming to the frequency component; and a delay-time setting unit for setting the acquired delay time in the delay unit.

Abstract: In a distortion compensation device which uses distortion compensation coefficients to subject distortion compensation processing to an input signal and supply the result of the distortion compensation processing to a distorting device, calculates the distortion compensation coefficients based on the input signal before distortion compensation and the feedback signal fed back from the output side of the distorting device, and stores the calculated distortion compensation coefficients in association with the input signal, (1) the feedback signal is AD-converted; (2) the AD-converted output is subjected to fast Fourier transform (FFT) processing; (3) the FFT calculation result is used to calculate the value of either the signal-to-noise ratio SNR, or the adjacent channel leakage power ratio ACLR, or the noise level; (4) the delay time occurring in the distorting device and feedback loop is adjusted such that the difference between the above calculated value at the current time and the above calculated value at

Abstract: A distortion compensating apparatus calculates a distortion compensation coefficient in such a manner that a difference signal between a reference signal, which is a transmit signal, and a feedback signal will be diminished, updates an old distortion compensation coefficient by the calculated distortion compensation coefficient and applies distortion compensation to the transmit signal based upon this distortion compensation coefficient. In this apparatus, a phase correcting interval, which is for correcting the phase difference between the reference signal and the feedback signal, and a distortion compensation coefficient updating interval are generated alternately, a correction is applied so as to null the phase difference in the phase correcting interval, and the distortion compensation coefficient is updated in the distortion compensation coefficient updating interval.

Abstract: In a distortion compensation device which uses distortion compensation coefficients to subject distortion compensation processing to an input signal and supply the result of the distortion compensation processing to a distorting device, calculates the distortion compensation coefficients based on the input signal before distortion compensation and the feedback signal fed back from the output side of the distorting device, and stores the calculated distortion compensation coefficients in association with the input signal, (1) the feedback signal is AD-converted; (2) the AD-converted output is subjected to fast Fourier transform (FFT) processing; (3) the FFT calculation result is used to calculate the value of either the signal-to-noise ratio SNR, or the adjacent channel leakage power ratio ACLR, or the noise level; (4) the delay time occurring in the distorting device and feedback loop is adjusted such that the difference between the above calculated value at the current time and the above calculated value at

Abstract: In an adaptive predistorter type distortion compensating apparatus for calculating a distortion compensating coefficient by using an adaptive algorithm so as to reduce an error between a reference signal and a feedback signal of a circuit which generates a distortion on the basis of the reference signal, and for compensating the distortion by providing the distortion compensating coefficient to the reference signal, a phase adjustment circuit is provided for determining a phase shift value which reduces a phase difference between a reference signal and a feedback signal, for correcting the phase of the reference signal or the feedback signal by the phase shift value, and for calculating the distortion compensating apparatus after the correction.