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: A distortion compensation apparatus includes an amplifier for amplifying an input signal, a calculation unit for obtaining a distortion compensation coefficient of the amplifier corresponding to an amplitude level of the input signal, based on the input signal input to the amplifier and an output signal output from the amplifier, a memory for storing the distortion compensation coefficient, obtained by the calculation unit, into a write address being made to correspond to the input signal amplitude level, a distortion compensation processing unit for reading out the distortion compensation coefficient from the readout address of the memory, and for performing distortion compensation processing of the input signal using the distortion compensation coefficient, and an address generator for generating the write address and the readout address, based on the input signal amplitude level.

Abstract: A radio transmission apparatus executing peak suppression processing to an input signal in at least two stages, includes a first peak detector detecting a first peak, a maximum peak among peaks exceeding a first threshold, for a plurality of envelopes included in a predetermined input signal section; a second peak detector detecting a second peak exceeding a second threshold, on the basis of each input signal envelope; a first peak suppression unit suppressing the predetermined input signal section to the limit of a first level based on the first peak; a modulation signal generation unit generating a modulated signal modulated from the input signal suppressed by the first peak suppression unit; and a second peak suppression unit suppressing the second peak to the limit of a second level by each modulated signal envelope based on the first level and the second peak.

Abstract: Disclosed is a method of controlling direction of radio-wave emission of a base-station transmitter which emits radio waves upon providing the radio waves with directivity in the direction of a receiver. Two antennas of a base station that are disposed at different positions transmit first and second signals that have been spread by mutually orthogonal spreading codes. A mobile station has a phase detector for receiving the first and second signals transmitted from respective ones of the antennas and obtaining a phase difference between these signals, and a direction estimator for calculating the direction of the mobile station, as seen from the base station, based upon the phase difference and for feeding back a signal representing the calculated direction from the mobile station to the base station. The transmitter of the base station transmits data toward the receiver in the calculated direction using a directional 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: A code multiplexing transmitting apparatus spread-spectrum modulates transmission data of a plurality of channels by spreading codes that differ from one another, combines the spread-spectrum signals of each of the channels and transmits the resultant spread-spectrum modulated signal. A spread-spectrum modulating unit for each channel includes a phase shifter for shifting, by a predetermined angle channel by channel, the phase of a position vector of the spread-spectrum modulated signal of each channel. As the result of such phase control, the phases of pilot signal portions of the spread-spectrum modulated signals of the respective channels are shifted relative to one another so that the peak values of the code-multiplexed signal can be suppressed.

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 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: 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 DC offset component that occurs in a quadrature modulation system, and that is contained in a modulated transmit signal, is compensated for with good accuracy. In a DC offset compensation method according to the present invention, a DC offset correction value obtained from the transmit signal is weighted in accordance with the signal level of an input signal which is transmit data input to the quadrature modulation system, and the DC offset component contained in the transmit signal is compensated for by using the thus weighted DC offset correction value.

Abstract: The present invention provides a peak suppression method, including a first step for detecting characteristic information of a peak part of a transmission signal; and a second step for changing a suppression method for the peak part based on the characteristic information.

Abstract: As in a conventional technology, a hard clipping process and a filtering process are performed on a transmission signal. An original transmission signal is subtracted from a signal on which the processes have been performed, and an inverse sign signal to the suppressed signal is retrieved. By giving a gain to the signal, and adding up to the original transmission signal, a peak voltage is suppressed. The gain can be a ratio of a difference signal between a hard clipped signal and an original transmission signal to a signal of suppression of a filtered signal from the original transmission signal, or a value determined by a simulation depending on the cutoff frequency of a low pass filter used in the filtering process.

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 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 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 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: The present invention reduces the scale of circuitry and shortens the code phase detection time needed to achieve initial synchronization. In a correlator for calculating correlation between a received spreading code contained in a received spread-spectrum signal and a reference spreading code, a combined code generator is included. The combined code generator outputs a combined spreading code by weighting and combining a plurality of phase-shifted reference spreading codes A1–AM. Further, an arithmetic circuit calculates correlation between the received spreading code and the plurality of phase-shifted reference spreading codes simultaneously. A phase detection circuit detects the phase difference between the received spreading code and a reference spreading code, namely the phase of the received spreading code from the results of the arithmetic operation.

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 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.