An RF generator in a dual frequency RF generation system. The RF generator detects IMD components resulting from interaction of the two frequencies. The IMD is reduced by adjusting the phase of the RF signal output by the RF generator. In various configurations, the IMD may also be reduced by applying a power adjustment value.

An apparatus for controlling the gain and phase of an input signal input to a power amplifier comprises a gain control loop configured to control the gain of the input signal based on power levels of the input signal and an amplified signal output by the power amplifier, to obtain a predetermined gain of the amplified signal, and a phase control loop configured to obtain an error signal related to a phase difference between a first signal derived from the input and a second signal derived from the amplified signal, and control the phase based on the error signal, to obtain a predetermined phase of the amplified signal. The phase control loop delays the first signal such that the delayed first signal and the second signal used to obtain the error signal correspond to the same part of the input signal. The apparatus may be included in a satellite.

An apparatus for controlling the gain and phase of an input signal input to a power amplifier comprises a gain control loop configured to control the gain of the input signal based on power levels of the input signal and an amplified signal output by the power amplifier, to obtain a predetermined gain of the amplified signal, and a phase control loop configured to obtain an error signal related to a phase difference between a first signal derived from the input and a second signal derived from the amplified signal, and control the phase based on the error signal, to obtain a predetermined phase of the amplified signal. The phase control loop delays the first signal such that the delayed first signal and the second signal used to obtain the error signal correspond to the same part of the input signal. The apparatus may be included in a satellite.

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.

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.

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.

An apparatus for controlling the gain and phase of an input signal input to a power amplifier comprises a gain control loop configured to control the gain of the input signal based on power levels of the input signal and an amplified signal output by the power amplifier, to obtain a predetermined gain of the amplified signal, and a phase control loop configured to obtain an error signal related to a phase difference between a first signal derived from the input and a second signal derived from the amplified signal, and control the phase based on the error signal, to obtain a predetermined phase of the amplified signal. The phase control loop delays the first signal such that the delayed first signal and the second signal used to obtain the error signal correspond to the same part of the input signal. The apparatus may be included in a satellite.

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.

An apparatus for controlling the gain and phase of an input signal input to a power amplifier comprises a gain control loop configured to control the gain of the input signal based on power levels of the input signal and an amplified signal output by the power amplifier, to obtain a predetermined gain of the amplified signal, and a phase control loop configured to obtain an error signal related to a phase difference between a first signal derived from the input and a second signal derived from the amplified signal, and control the phase based on the error signal, to obtain a predetermined phase of the amplified signal. The phase control loop delays the first signal, such that the delayed first signal and the second signal used to obtain the error signal correspond to the same part of the input signal. The apparatus may be included in a satellite.

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.