Abstract:
The phase of a transmitted signal is regulated in a device which is part of a system for electromagnetic signal transmission. The transmitted signal has periods when it contains information and periods when it does not contain information. The modulation position of a phase shifter which has a linear and a non-linear range is controlled. Power of the signal is amplified. Unwanted phase shifts in the signal transmitted by the device caused within the power amplifier are detected, and the information content of the signal is detected. The phase shifter is reset to a particular predetermined modulation position in the event of detection of the absence of information in the signal. The predetermined modulation position to which the phase shifter is reset is preferably situated within the linear range of the phase shifter.
Abstract:
The present disclosure describes a method and system for linearizing an amplifier using transistor-level dynamic feedback. The method and system enables nonlinear amplifiers to exhibit linear performance using one or more of gain control elements and phase shifters in the feedback path. The disclosed method and system may also allow an amplifier to act as a pre-distorter or a frequency/gain programmable amplifier.
Abstract:
A system and method for linearizing a power amplifier using digital predistortion technique is provided including processing circuitry, the processing circuitry configured to apply a digital predistortion function based on a weighted static polynomial function, a weighted dynamic polynomial function and a threshold parameter which splits the nonlinear transfer characteristics of the device under test into a region where the static nonlinearity predominates and a region where the dynamic distortions predominate.
Abstract:
an amplifier amplifies electrical power of signals. A calculating unit calculates a cumulative value for each of first samples and second samples, between which a difference in electrical power or phase is within a first range, in a first sample group and a second sample group corresponding to a first signal that is a signal before amplification in the amplifier and a second signal that is a signal after amplification in the amplifier. Then, the calculating unit calculates, by using the calculated cumulative value, a phase difference between the first signal and the second signal. The correction unit corrects the phase difference by using a correction amount calculated from the phase difference. The updating unit updates, by using the first signal and the second signal of which the phase difference is corrected, a distortion compensation coefficient that is used to compensate nonlinear distortion generated in the amplifier.
Abstract:
A single or multistage signal predistorter includes an input coupled to receive an information signal comprising input samples and an output coupled to the high power amplifier, the signal predistorter configured to receive an input sample, generate a distortion sample based on an estimate of nonlinearity of the high power amplifier at an operating saturation level, modify the input sample with a correction term to generate a predistortion signal, wherein the correction term is proportional to the distortion sample, and further wherein the predistortion signal comprises the information signal modified to account for nonlinearities in the high power amplifier.
Abstract:
The present invention implements a series of analog gain and phase correction circuits in each leg of the N-way Doherty to significantly reduce amplitude modulation to amplitude modulation (AM-AM) and amplitude modulation to phase modulation (AM-PM), distortion. The correction blocks comprise gain and phase corrections and optionally an additional gain block. The phase corrections include at least a phase offset and may include an optional non-linear element such as a diode pre-distorter. The pre-distortion circuitry is intended to reduce the necessary complexity of the DPD and reduce the DPD cost and power consumption. The gain and phase corrections can be calculated from computational optimization to minimize the AM-AM and AM-PM distortion. The gain and phase corrections can also be calculated from the AM-AM and AM-PM data which can be output from common DPD systems and laboratory characterization equipment.
Abstract:
A distortion compensation apparatus includes a pre-distorter, a gain control unit, and a learning unit. The pre-distorter adds distortion according to compensation coefficients to individual input signals prior to the input signals being input to a power amplifier. The gain control unit applies gain control to individual feedback signals fed back from the power amplifier according to a maximum level of the feedback signals within a time frame. The learning unit updates the compensation coefficients used by the pre-distorter, using the feedback signals subjected to the gain control by the gain control unit.
Abstract:
A phase noise correction device having a function for accurately detecting a phase noise component and capable of reducing a load on a reception device is provided. A phase noise correction device for correcting a phase noise generated in a local oscillator includes: a division section that divides a signal generated in the local oscillator; a reference signal generation section that generates a signal of the same frequency as that of the divided signal; a phase difference detection section that detects a phase difference between the divided signal and the generated reference signal; and a phase noise correction section that gives a phase rotation to a baseband signal in the direction that cancels the phase noise according to the detected phase difference as a phase noise component.
Abstract:
A radio frequency (RF) power amplifier system is provided, in which a distortion of the RF output signal from the power amplifier is estimated by comparing the RF output signal with reference modulation information. The supply voltage to the power amplifier is adjusted so that the estimated distortion of the RF output signal corresponds to a predetermined distortion level. The predetermined distortion level is set to represent an acceptable distortion level at the RF output signal.
Abstract:
Systems, circuitries, and methods for predistorting a digital signal in a transmit chain based on a predistortion function are provided. A method includes shifting a center frequency of an input signal by an offset to generate an adapted signal; predistorting the adapted signal based on a predistortion function to generate a predistorted adapted signal; reverting the shifting of the center frequency of the predistorted adapted signal by the offset to generate a predistorted signal; and causing transmission of the predistorted signal by a transmit chain.