Abstract: When a distortion correction coefficient, which is calculated according to a signal input to a power amplifier and a signal output from the power amplifier, is larger than a first threshold, a distortion correction coefficient corresponding to the input signal is updated to the first threshold. When the calculated distortion correction coefficient is equal to or smaller than the first threshold, the distortion correction coefficient corresponding to the input signal is updated to the calculated distortion correction coefficient.

Abstract: A distortion compensating amplifier including a forward circuit and a feedback circuit and performing distortion compensation of a signal in the forward circuit by use of a gain of the feedback circuit, includes a detecting unit which detects that the gain of the forward circuit is changed, a calculating unit which calculates, when the detecting unit detects that the gain of the forward circuit is changed, the gain of the feedback circuit on the basis of an input signal to the forward circuit and an output signal from the forward circuit, and a feedback gain updating unit which updates the present gain of the feedback circuit with the gain calculated by the calculating unit.

Abstract: In a transmission device including an RF power amplifier with less number of terminals for monitoring an input/output signal of the RF power amplifier, there are provided with an input signal detector detecting the input signal; an output signal detector detecting the output signal; a first power amplifier switch switching ON or OFF the power amplifier; a monitor terminal; and an RF switch selecting an input signal or output signal of the power amplifier to be transmitted to the monitor terminal, in association with the first power amplifier switch being switched ON or OFF.

Abstract: A direct-current-offset correction device includes a digital-to-analog converter that converts a digital signal into an analog signal, a modulator that modulates the analog signal to generate a modulated signal, a direct-current-offset correction value calculation unit that calculates a direct-current-offset correction value as a reverse characteristic component of a carrier leak occurring in the modulated signal based on a demodulated signal which is demodulated by feeding back the modulated signal, a direct-current-offset correction unit that corrects a direct-current-offset on the digital signal based on the direct-current-offset correction value, a correction value detection unit that detects whether or not the direct-current-offset correction value is zero or a neighboring value of zero, and an offset generation unit that superimposes a direct-current-offset component on the analog signal based on a detection result of the correction value detection unit.

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 compensation amplification device which supplies a transmission signal while a distortion of the amplified transmission signal is compensated, the distortion compensation amplification device including a correction unit which corrects a carrier leak and an image of the transmission signal based on a correction value. The distortion compensation amplification device includes a modulation unit which modulates the transmission signal supplied from the correction unit. The distortion compensation amplification device includes a correction value calculating unit which calculates the correction value based on the transmission signal supplied from the modulation unit. The distortion compensation amplification device includes a test signal output unit which supplies a test signal to the correction unit in order to calculate the correction value of the correction value calculating unit when the transmission signal is not transmitted.

Abstract: There is provided a distortion compensation apparatus for compensating distortion of an output of a power amplifier included in a radio transmitter. The distortion compensation apparatus includes a difference value calculator to calculate a difference value between a reference signal and a feedback signal, where the reference signal is branched from an input signal to the power amplifier and the feedback signal is branched from an output from the power amplifier; an integrator to accumulate the difference value; and a failure determiner to determine based on the accumulated difference value whether or not a failure has occurred or not.

Abstract: A cyanide-free copper-zinc alloy electroplating bath is provided which can form a uniform and glossy alloy layer having the desired composition even at a higher current density than that for a conventional electroplating bath, and which is excellent in productivity. The copper-zinc alloy electroplating bath comprises at least one selected from a copper salt, zinc salt, alkali metal pyrophosphate, and amino acid or a salt thereof, and has a pH of 8.5 to 14. The pH is preferably 10.5 to 11.8; and the concentration of the amino acid or a salt thereof is preferably 0.08 mol/L to 0.22 mol/L, more preferably 0.1 mol/L to 0.13 mol/L. As the amino acid or a salt thereof, histidine or a salt thereof may be preferably used.

Abstract: A distortion compensation apparatus having a circuit configured to perform power amplification of a transmission signal; and a circuit configured to feedback the transmission signal output from the circuit configured to perform power amplification and obtain a demodulated signal of the transmission signal, while calculating and holding a distortion compensation coefficient with which an error between the demodulated signal and the transmission signal before the power amplification becomes minimum, to perform distortion compensation of the transmission signal based on the distortion compensation coefficient and provide the compensated transmission signal to the circuit configured to perform the power amplification, the distortion compensation apparatus includes: a gain adjustment unit to adjust a gain of the transmission signal; and a gain control unit to adaptively adjust a gain of the gain adjustment unit based on the held distortion compensation coefficient.

Abstract: Distortion-compensation amplification apparatus that can obtain an appropriate error vector magnitude without increasing power consumption and can suppress the distortion of a transmission signal appropriately. A distortion compensation section applies distortion compensation to the transmission signal. An amplification section amplifies the transmission signal to which distortion compensation has been applied by the distortion compensation section. A frequency component calculation section calculates the power of frequency components of the transmission signal amplified by the amplification section. A peak suppression section suppresses the peak value of the transmission signal input to the distortion compensation section in accordance with the power of the frequency components calculated by the frequency component calculation section.

Abstract: A distortion compensating technique applied to a transmitter for transmitting a quadrature modulated signal in a wireless digital communication system is provided. A phase adjustment value is determined for a quadrature demodulated feedback signal based on comparison between the feedback signal and a reference signal to be transmitted from the transmitter. This phase adjustment value is compared with the previous phase adjustment value. If the comparison result between the current and previous phase adjustment values satisfies a prescribed condition, correction for quadrature modulation, such as DC offset correction, orthogonality correction, or IQ amplitude correction, is performed.

Abstract: A direct-current-offset correction device includes a digital-to-analog converter that converts a digital signal into an analog signal, a modulator that modulates the analog signal to generate a modulated signal, a direct-current-offset correction value calculation unit that calculates a direct-current-offset correction value as a reverse characteristic component of a carrier leak occurring in the modulated signal based on a demodulated signal which is demodulated by feeding back the modulated signal, a direct-current-offset correction unit that corrects a direct-current-offset on the digital signal based on the direct-current-offset correction value, a correction value detection unit that detects whether or not the direct-current-offset correction value is zero or a neighboring value of zero, and an offset generation unit that superimposes a direct-current-offset component on the analog signal based on a detection result of the correction value detection unit.

Abstract: The apparatus includes: distortion amount detector which detects the amount of distortion of an output signal of an amplifier; parameter holder which holds a parameter having been set therein, the parameter holder being capable of varying the difference according to the parameter set therein; parameter corrector which corrects the parameter held in the parameter holder in such a manner that the distortion amount detected by the distortion amount detector is improved; noise component detector which detects a noise component that can be caused in the output signal resulting from a quadrature modulation; and noise component remover which performs processing for removing the noise component detected by the noise component detector. This arrangement makes it possible to suppress image frequency component generation in an output signal of the amplifier accompanying quadrature modulation and to optimize parameters in distortion compensation.

Abstract: A distortion compensation amplification device which supplies a transmission signal while a distortion of the amplified transmission signal is compensated, the distortion compensation amplification device including a correction unit which corrects a carrier leak and an image of the transmission signal based on a correction value. The distortion compensation amplification device includes a modulation unit which modulates the transmission signal supplied from the correction unit. The distortion compensation amplification device includes a correction value calculating unit which calculates the correction value based on the transmission signal supplied from the modulation unit. The distortion compensation amplification device includes a test signal output unit which supplies a test signal to the correction unit in order to calculate the correction value of the correction value calculating unit when the transmission signal is not transmitted.

Abstract: A data sending and receiving apparatus includes a sending state acquiring unit that monitors and acquires at least one of a sending process state indicating whether the sending process of the transmission data is being executed, and a signal strength of the transmission data; a signal strength measuring unit that measures a signal strength of the reception data; a measured value correcting unit that corrects a measured value of the signal strength of the reception data measured by the signal strength measuring unit, in accordance with at least one of the sending process state and an acquisition result of the signal strength of the transmission data acquired by the sending state acquiring unit; and a demodulating unit that demodulates the reception data using a corrected measured value corrected by the measured value correcting unit.

Abstract: A reference signal and a feedback signal are written to memory and the state of a power value of a reference signal is used for judging whether the current signal is in a normal state, burst state, non-modulation state or no-wave transmission state. If the state is judged to be the burst state or no-wave transmission state, a DC offset correction is performed by selecting a feedback signal type DC offset correction method in which a DC offset is corrected by using only a feedback signal. If the state is judged to be the normal state or non-modulation state, a DC offset correction is performed by selecting a reference signal type DC offset correction method in which a DC offset is corrected by using a differential signal between the reference signal and feedback signal.

Abstract: Distortion-compensation amplification apparatus that can obtain an appropriate error vector magnitude without increasing power consumption and can suppress the distortion of a transmission signal appropriately. A distortion compensation section applies distortion compensation to the transmission signal. An amplification section amplifies the transmission signal to which distortion compensation has been applied by the distortion compensation section. A frequency component calculation section calculates the power of frequency components of the transmission signal amplified by the amplification section. A peak suppression section suppresses the peak value of the transmission signal input to the distortion compensation section in accordance with the power of the frequency components calculated by the frequency component calculation section.

Abstract: A step size parameter ? is adaptively varied when a distortion compensation coefficient is calculated in a distortion compensation apparatus, relation between transmission signal level and step size parameter ? is considered. The distortion compensation apparatus includes a memory storing distortion compensation coefficient in a designated write address, and outputting distortion compensation coefficient being stored in a designated readout address; a predistortion section performing distortion compensation processing onto a transmission signal, using the distortion compensation coefficient being output from memory; and a distortion compensation section calculating an update value of distortion compensation coefficient, based on error component existent between transmission signal before distortion compensation processing and transmission signal after being amplified by an amplifier.

Abstract: A distortion compensation apparatus shortens the time until start of the transmission. The distortion compensating apparatus for amplifying the transmitted signal after implementation of the distortion compensation process thereto comprises a coefficient memory operable to store coefficients used for the distortion compensation process, an initial value memory operable to store the initial values of the coefficients, and a controller which controls the coefficient memory to store, with limitation, only the coefficients corresponding to the first portion among those stored in the initial value memory for the initial write to the coefficient memory and to store thereafter the coefficients corresponding to the second portion.

Abstract: An address frequency operation unit counts frequencies of occurrences of addresses output by an address conversion unit 14, and a CPU 16 rewrites an address conversion table in the address conversion unit 14 based on a comparison between the counted result and a threshold value. When the frequency of the address is lower than the threshold value, the frequency of occurrence of an output address is increased by increasing the number of input addresses corresponding to one output address. Also, distortion in an output signal which is fed back is detected and the address conversion table is rewritten so that the distortion is decreased.