85results about "Amplitude adaptive predistortion" patented technology

A RF-digital hybrid mode power amplifier system for achieving high efficiency and high linearity in wideband communication systems is disclosed. The present invention is based on the method of adaptive digital predistortion to linearize a power amplifier in the RF domain. The power amplifier characteristics such as variation of linearity and asymmetric distortion of the amplifier output signal are monitored by the narrowband feedback path and controlled by the adaptation algorithm in a digital module. Therefore, the present invention could compensate the nonlinearities as well as memory effects of the power amplifier systems and also improve performances, in terms of power added efficiency, adjacent channel leakage ratio and peak-to-average power ratio. The present disclosure enables a power amplifier system to be field reconfigurable and support multi-modulation schemes (modulation agnostic), multi-carriers and multi-channels. As a result, the digital hybrid mode power amplifier system is particularly suitable for wireless transmission systems, such as base-stations, repeaters, and indoor signal coverage systems, where baseband I-Q signal information is not readily available.

An adaptive predistortion linearized amplifier system employing selective sampling is disclosed. Two selective sampling methods of identifying valid measurements using information from the input signal are disclosed. The selective sampling process improves the convergence properties of tuning algorithms based on minimizing the gain error variance. It also reduces the number of data samples processed by the estimator used in the tuning process.

Apparatus for amplifying an input signal having an input signal power includes a power amplifier, which is adapted to amplify an intermediate signal so as to generate an output signal, and which is characterized by a non-linearity. A non-linear filter is coupled to decompose the input signal into a series of input signal components, each such component proportional to a product of the input signal by a respective integer power of the input signal power, and is adapted to filter the signal components responsively to the non-linearity so as to generate the intermediate signal for input to the power amplifier.

A transmitter circuit (200, 400, 510) and method reduces amplitude modulation distortion in an amplifier (210). The transmitter circuit (200, 400, 510) includes a power control error data generator (230), a feedforward predistortion data generator (240), feedforward adder logic (250) and the amplifier (210). The power control error data generator (230) receives amplitude modulation data (252) and an RF coupled output signal (254) and, in response, produces power control error data (256). The feedforward predistortion data generator (240) receives the amplitude modulation data (252) and, in response, produces feedforward predistortion data (258). The feedforward adder logic (250) receives the power control error data (256) and the feedforward predistortion data (258) and, in response, produces power control data (260). The amplifier (210) receives the power control data (260) and an RF input signal (261) and, in response, produces an RF output signal (262), such that the power control data (260) reduces amplitude modulation distortion in the RF output signal (262).

A method, apparatus, and computer program for modeling mathematically an effect of a plurality of factors on signal distortion caused by a non-linear amplifier are provided. First, there is computed a global model which incorporates a combined effect of the plurality of factors on signal distortion caused by the non-linear amplifier. Before applying the pre-distorted transmission signal to the non-linear amplifier, a transmission signal is pre-distorted with coefficients derived from the global model thus compensating for the signal distortion caused by the non-linear 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.

Disclosed is a distortion compensating amplifier having a distortion compensator for compensating for distortion of an amplifier by updating distortion compensation coefficients so as to null a difference between a transmit signal and a feedback signal, and subjecting the transmit signal to distortion compensation processing using the distortion compensation coefficients, an amplifier for amplifying the transmit signal, which has undergone distortion compensation, in order to transmit the signal from an antenna, and a feedback unit for inputting an output signal from the amplifier to a distortion compensation coefficient updater in the distortion compensator as the feedback signal. Whether the level of an unwanted-wave signal that penetrates the amplifier from space via an antenna is greater than a set level is monitored. If the level of the unwanted-wave signal is above the set level, processing for updating distortion compensation coefficients is suspended. If the level of the unwanted-wave signal is below the set level, then processing for updating distortion compensation coefficients is resumed.

There is disclosed an amplifier arrangement comprising a plurality of amplifiers each arranged to amplify one of a plurality of different input signals, the arrangement comprising an envelope tracking modulator for generating a common power supply voltage for the power amplifiers, and further comprising an envelope selector adapted to receive a plurality of signals representing the envelopes of the plurality of input signals, and adapted to generate an output envelope signal representing the one of the plurality of envelopes having the highest level at a particular time instant as the input signal for the envelope tracking modulator.

A power amplifier cell includes a first input arranged to receive an in-phase control signal, a second input arranged to receive a quadrature control signal, an input stage arranged to output a drive signal based at least partly on the received in-phase and quadrature control signals, and an output stage arranged to receive at an input thereof the drive signal output by the input stage, and to generate an output signal for the power amplifier cell in response to the received drive signal.

The invention discloses a calculating method of digital pre-distortion parameters and a pre-distortion system and relates to the field of digital pre-distortion processing. The calculating method of digital pre-distortion parameters and the pre-distortion system are used for achieving a good signal processing effect and simplifying calculating complexity of models. The calculating method of digital pre-distortion parameters includes: acquiring pre-distortion signals already subjected to pre-distortion processing and first feedback signals already subjected to power amplifying processing after periodic processing starts; performing rated linear gain eliminating on the first feedback signals to obtain second feedback signals; determining pre-distortion parameters according to a matrix formed by the second feedback signals and a matrix formed by the pre-distortion signals; updating a pre-distortion parameter index table according to the determined pre-distortion parameters.

An exemplary system comprises a linearizer, a power amplifier, and a feedback block. The linearizer may be configured to use a predistortion control signal to add predistortion to a receive signal to generate a predistorted signal. The power amplifier may be configured to amplify power of the predistorted signal to generate a first amplified signal. The power amplifier may also add high side and low side amplifier distortion to the predistorted signal. The high side and low side amplifier distortion may cancel at least a portion of the predistortion. The feedback block may be configured to capture a feedback signal based on a previous amplified signal from the power amplifier, to determine high side and low side distortion of the captured feedback signal, and to generate the predistortion control signal based on the determined high side and low side distortion.

A pre-distortion method includes: receiving an input data; and obtaining a pre-distorted output by inputting the input data into a pre-distortion function, wherein the pre-distortion function is determined according to a power amplifier. A pre-distortion apparatus includes a receiver and a pre-distortion unit. The receiver is utilized for receiving an input data. The pre-distortion unit is utilized for obtaining a pre-distorted output by inputting the input data into a pre-distortion function, wherein the pre-distortion function is determined according to a following power amplifier. A non-transitory machine readable medium stores a program code executed for performing steps of the proposed pre-distortion method.