Patent application number | Description | Published |
20130049861 | MODULATOR AND AN AMPLIFIER USING THE SAME - A linear amplification with nonlinear components (LINC) modulator is provided. The LINC modulator includes: a separator that generates a plurality of constant envelope signals from a source signal; a processor that receives an input signal and detects and removes a phase jump in phase trajectory of the input signal to generate a first signal having a continuous phase trajectory and a second signal having a discontinuous phase trajectory; and a quadrature modulator that mixes the first signal with the second signal to reconstruct the input signal. | 02-28-2013 |
20130049877 | MODULATOR AND AN AMPLIFIER USING THE SAME - The LINC modulator includes: a separator that generates a plurality of constant envelope signals from a source signal; a plurality of arms through which the plurality of the constant envelope signals are passed, wherein each arm includes a filter that compares frequencies of components of the constant envelope signals with a threshold frequency to generate a first signal including a first frequency part of the source signal, the first frequency part being composed of frequencies lower than a predetermined frequency; a processor that generates a second signal including a second frequency part of the source signal whose frequencies are different from the first frequency part and performs a frequency signal distortion of the second signal to generate a distorted signal; and a quadrature modulator that multiplies the first and distorted signals to reconstruct the constant envelope signals. | 02-28-2013 |
20130120062 | ADAPTIVE LINEARIZER WITH NARROWBAND FEEDBACK PATH - An ISI Replica unit is provided, which produces interference components similar to one due to LPF into the output of HPA MODEL unit. An HPA MODEL unit models the characteristic of HPA using the output signal of the predistorter and an error signal obtained by subtracting a feedback signal from the output of the ISI Replica so that the error signal approaches zero. The feedback signal is used after filtration by LPF, thereby including interference components. The error signal obtained by the feedback signal after LPF and the output signal of ISI Replica unit includes few interference components, thereby modeling by the HPA MODEL unit becomes accurate and the linearization performances become better. | 05-16-2013 |
20130194038 | SIGNAL PROCESSING APPARATUS AND AMPLIFICATION APPARATUS - A signal processing apparatus includes a corrector that corrects a digital signal in accordance with a correction value, a converter that converts the digital signal corrected by the corrector into an analog signal, a sample-and-hold unit that holds an instantaneous value of the analog signal that has been obtained by the converter and that has been amplified by an amplifier for a certain frequency that is smaller than twice a maximum frequency of the analog signal, a digitizer that converts the instantaneous value held by the sample-and-hold unit into a digital value when the digitizer received an operation clock having the certain frequency, and an updater that updates, on the basis of the digital value obtained by the digitizer, the correction value of the corrector such that the correction value becomes a correction value that reduces nonlinear distortion in the analog signal amplified by the amplifier. | 08-01-2013 |
20130195221 | SIGNAL PROCESSING SYSTEM AND SIGNAL PROCESSING METHOD - A signal processing system is provided. The signal processing system includes: a peak-to-average ratio (PAPR) reducer that reduces a peak-to-average ratio (PAPR) of an input signal x(n), a clipping noise processing system that generates an equivalent clipping noise signal ε* | 08-01-2013 |
20140003553 | PREDISTORTION APPARATUS FOR POWER AMPLIFIER | 01-02-2014 |
20140049324 | LINC POWER AMPLIFIER - A LINC power amplifier selects, based on an amplitude of an input signal, partial signals used for combination, and determines, based on the amplitude and a phase of the input signal, an amplitude and a phase of the selected partial signals so that a range of output power that the LINC power amplifier operates a given efficiency is expanded, inputs the selected partial signals to corresponding power amplifiers, and combines signals obtained by amplification of the selected partial signals by the corresponding power amplifiers. | 02-20-2014 |
20140167844 | DISTORTION COMPENSATION DEVICE AND DISTORTION COMPENSATION METHOD - A distortion compensation device includes: a distortion compensator configured to output, to a power amplifier, a predistortion signal obtained by performing distortion compensation processing on a transmission signal by using a distortion compensation coefficient, wherein the distortion compensator limits bands of a reference signal and a feedback signal so that the bands fall in a pass band and updates the distortion compensation coefficient based on an error between the reference signal and the feedback signal, the reference signal corresponding to the predistortion signal, the feedback signal corresponding to an output feedback of the power amplifier. | 06-19-2014 |
20140187183 | TRANSMISSION SIGNAL POWER CONTROL DEVICE AND COMMUNICATION APPARATUS - A transmission signal power control device includes: at least one low-power attenuator configured to attenuate amplitude of a transmission signal when an absolute value of the amplitude of the transmission signal is smaller than or equal to a clipping threshold; a power amplifier configured to amplify the transmission signal output from the at least one low-power attenuator; and a control unit configured to stop operation of the power amplifier when the absolute value of the amplitude of the transmission signal is smaller than or equal to a value and operate the power amplifier when the absolute value of the amplitude of the transmission signal is larger than the value. | 07-03-2014 |
20140191798 | TRANSMISSION SIGNAL POWER CONTROL APPARATUS, COMMUNICATION APPARATUS AND PREDISTORTION COEFFICIENT UPDATING METHOD - A transmission signal power control apparatus includes a power amplifier model unit which generates a learning digital signal by multiplying part of a predistortion signal by model coefficients which tentatively represent the input-output characteristics of a power amplifier, and an adaptive low-pass filter which generates a pseudo feedback signal by attenuating the high frequency components of the learning digital signal by multiplying the learning digital signal by weighting coefficients. Then, the power amplifier model unit updates the model coefficients such that the error between the feedback signal whose the high frequency components are attenuated by the low-pass filter and which is digitized, and the pseudo feedback signal is minimized, and the adaptive low-pass filter updates the weighting coefficients such that the error is minimized. | 07-10-2014 |
20140347132 | POWER AMPLIFIER APPARATUS, TRANSMITTER APPARATUS, AND METHOD OF CONTROLLING THE POWER AMPLIFIER APPARATUS - A power amplifier apparatus includes an amplifier configured to amplify an input signal converted into an analog signal, a distortion compensator circuitry configured to perform a pre-distortion process to an input signal at a second sampling rate higher than a first sampling rate at which the input signal is converted into an analog signal, a remover configured to remove a frequency component exceeding a frequency band corresponding to the first sampling rate from the input signal subjected to the pre-distortion process, a first rate converter configured to convert a sampling rate of the input signal from which the frequency component is removed from the second sampling rate to the first sampling rate, and a first signal converter configured to convert the input signal the sampling rate of which is converted into an analog signal at the first sampling rate to supply the input signal converted into the analog signal to the amplifier. | 11-27-2014 |
20150028947 | DISTORTION COMPENSATION APPARATUS AND METHOD - A distortion compensation apparatus compensates for non-linear distortion of a power amplifier. The distortion compensation apparatus includes a pre-distorter, a learning unit, and a gain control unit. During training of the pre-distorter, the learning unit repeatedly updates a compensation coefficient on the basis of signals output from the power amplifier. While the training continues after update of the compensation coefficient, the gain control unit performs gain control on a signal before input to the power amplifier. | 01-29-2015 |