CN-122001308-A - Predistortion-based broadband power amplifier linearization method and system

CN122001308ACN 122001308 ACN122001308 ACN 122001308ACN-122001308-A

Abstract

The invention belongs to the technical field of data processing of computer information subjects, and relates to a broadband power amplifier linearization method and system based on predistortion, wherein the method comprises the steps of collecting and preprocessing radio frequency input baseband signals, actual output baseband signals and tube core heat flow data of the broadband power amplifier to obtain an initial data set; the method comprises the steps of calculating transient heat dissipation gradients at each sampling moment based on signal energy difference and die temperature change rate, combining broadband distribution characteristics of radio frequency input baseband signals to obtain broadband thermal distortion factors at each sampling moment, dynamically tracking and compensating cross term coefficients of a generalized memory polynomial based on the distortion factors to obtain update coefficients, and reconstructing predistortion signals by using the update coefficients to realize high-linearity output of a broadband power amplifier. The dynamic response speed of coefficient updating can be improved, nonlinear distortion caused by power and heat release can be effectively counteracted, and the linearity and stability of high-power broadband radio frequency test are improved.

Inventors

CHENG XIAONING
LIU MING
HUA LEI

Assignees

西安安泰测试科技有限公司

Dates

Publication Date: 20260508
Application Date: 20260410

Claims (10)

1. A predistortion-based wideband power amplifier linearization method, comprising: Acquiring a radio frequency input baseband signal, an actual output baseband signal and die heat flow data of a broadband power amplifier, and preprocessing the radio frequency input baseband signal, the actual output baseband signal and the die heat flow data to obtain an initial data set; Based on the energy difference between the radio frequency input baseband signal and the actual output baseband signal in the initial data set and the change rate of the tube core heat flow data in unit time, obtaining a transient heat dissipation gradient corresponding to each sampling moment; based on the transient heat dissipation gradients corresponding to the sampling moments, and combining the broadband distribution characteristics of the radio frequency input baseband signals corresponding to the sampling moments, calculating and obtaining broadband thermal distortion factors corresponding to the sampling moments; Based on broadband thermal distortion factors corresponding to each sampling time, dynamically tracking and compensating the cross term coefficients of the generalized memory polynomial to obtain updated coefficients of the generalized memory polynomial after dynamic tracking and compensation; and reconstructing the predistortion signal based on the update coefficient after dynamic tracking compensation corresponding to each sampling time, and realizing the high linearity output of the broadband power amplifier.
2. The linearization method of broadband power amplifier based on predistortion according to claim 1, wherein the obtaining of the initial data set comprises mapping the radio frequency input baseband signal, the actual output baseband signal and the die heat flow data to the same time domain index to finish high-precision time stamp alignment, then sequentially performing outlier rejection, noise filtering and missing value interpolation processing, introducing a sliding window-based data interception mechanism, setting a fixed preset length as the length of the sliding window, setting a sliding step length for controlling the movement of the sliding window, wherein the sliding step length is half of the preset length, intercepting the preprocessed data flow into a plurality of effective data fragments through the sliding window, and forming the initial data set by the effective data fragments.
3. A method for linearizing a wideband power amplifier based on predistortion according to claim 2, wherein said obtaining transient heat dissipation gradients corresponding to each sampling instant comprises: ; in the formula, Is the first Transient heat dissipation gradients at each sampling instant; Is an index of the sampling instant; 、 Respectively the first in the sliding window A radio frequency input baseband signal of each sampling point and a radio frequency input baseband signal envelope; 、 Respectively the first in the sliding window Actual output baseband signals of the sampling points and actual output baseband signal envelopes; Is the index of the sampling point in the sliding window; Is the theoretical linear gain of the wideband power amplifier; Is the first Die heat flow data for each sampling instant; Is the first Die heat flow data for each sampling instant; is the sampling time interval; Is the preset length of the set sliding window; is a constant that prevents the denominator from being 0.
4. A method for linearizing a wideband power amplifier based on predistortion according to claim 3, wherein the method for obtaining the theoretical linear gain of the wideband power amplifier comprises: when the broadband power amplifier is in a low-power linear working range, a group of standard test baseband signals with known amplitude are input into the broadband power amplifier through a baseband processing unit of a test instrument, standard test output baseband signals output by the broadband power amplifier are synchronously collected, the ratio of the envelope amplitude of the standard test output baseband signals to the envelope amplitude of the standard test baseband signals is calculated, and the average value of multiple test results is taken to obtain theoretical linear gain.
5. The method for linearizing a wideband power amplifier based on predistortion according to claim 2, wherein the wideband distribution characteristics of the radio frequency input baseband signal corresponding to each sampling time include a statistical variance of an envelope of the radio frequency input baseband signal in a sliding window to which each sampling time belongs, a physical cross-band bandwidth limit set by a test system, and a preset environmental reference normal temperature.
6. The method for linearizing a wideband power amplifier based on predistortion according to claim 2, wherein obtaining the wideband thermal distortion factor for each sampling instant comprises: ; in the formula, Is the first Broadband thermal distortion factors corresponding to the sampling moments; Is of dimension Is used for normalizing the total coefficient of the (a); Is the first Transient heat dissipation gradients at each sampling instant; Is the first Statistical variance of the envelope of the radio frequency input baseband signal in the sliding window to which the sampling time belongs; is a physical cross-band bandwidth limit; is an environmental standard normal temperature; Is made of natural constant As a logarithmic function of the base; Is an index of the sampling instant; Is an absolute value symbol.
7. The predistortion-based wideband power amplifier linearization method as set out in claim 1, wherein said dynamically tracking and compensating the cross term coefficients of the generalized memory polynomial to obtain updated coefficients of the generalized memory polynomial after dynamically tracking and compensating comprises: ; in the formula, Is the update coefficient of generalized memory polynomial after dynamic tracking compensation; The generalized memory polynomial original cross term coefficient is obtained after the last long-period full matrix coefficient is updated; Is an index of the signal envelope delay memory depth; Is an index of the advanced memory depth of the signal envelope; Nonlinear order of generalized memory polynomial; Is an index of the sampling instant; Is the memory time span corresponding to the current cross item; Is the first Broadband thermal distortion factors corresponding to the sampling moments; is the maximum distortion tolerance constant; Is a hyperbolic tangent function.
8. The predistortion-based wideband power amplifier linearization method as set out in claim 7, wherein the signal envelope delay memorizes the index of the depth Index of advanced memory depth of signal envelope Nonlinear order of generalized memory polynomial Memory time span The setting method of (2) comprises the following steps: Index of signal envelope delay memory depth The value range is 0 to 32 according to the memory effect depth determination of the broadband power amplifier And (3) with Matching memory span range of memory polynomials, the value range is 0-16, the said Presetting a value of 3 to 5 according to nonlinear characteristics of the broadband power amplifier and compensation accuracy requirements, wherein the value is 3 to 5 From the following components And (3) with Taking absolute value after making difference value.
9. The predistortion-based wideband power amplifier linearization method as set out in claim 1, wherein said reconstructing the predistortion signal achieves a high linearity output of the wideband power amplifier, comprising: the method comprises the steps of dynamically tracking and compensating a wide memory polynomial, substituting an updating coefficient set of the wide memory polynomial after compensation into a wide memory polynomial operation engine of a test instrument one by one, calling the updating coefficient set, performing inner product operation on the updating coefficient set and a wide frequency band radio frequency input baseband signal acquired in real time to generate a predistortion offset signal, keeping the signal format and the bandwidth range of the predistortion offset signal consistent with those of the radio frequency input baseband signal, sending the predistortion offset signal into a radio frequency analog link of the test instrument, preprocessing the radio frequency analog link, and inputting the predistortion offset signal into a wide frequency band power amplifier for high-power amplification, thereby realizing high-linearity output of the wide frequency band power amplifier.
10. A predistortion-based broadband power amplifier linearization system comprising a processor and a memory, the memory storing computer program instructions that, when executed by the processor, implement a predistortion-based broadband power amplifier linearization method in accordance with any of claims 1-9.

Description

Predistortion-based broadband power amplifier linearization method and system Technical Field The invention belongs to the technical field of data processing of computer information subjects, and relates to a broadband power amplifier linearization method and system based on predistortion, which are used for correcting or eliminating distortion signals output by a power amplifier. Background In the field of precision test and measurement, a broadband power amplifier is a core device for high-power output of a radio frequency test instrument, such as a signal generator, a network analyzer and the like, and in order to eliminate nonlinear distortion generated when the broadband power amplifier works at high power, the industry widely adopts a digital predistortion technology to reversely compensate an input signal, so that the linearity of test output is improved. The generalized memory polynomial algorithm is used as a core technical means of the current industry mainstream, and the fitting and compensation precision of the strong memory effect of the broadband signal can be greatly improved by introducing the lead and lag intersection terms of the signal envelope. Aiming at the influence of the heat effect on linearity, some improvements are also proposed in the prior art. For example, patent application document 1 (CN 117040450B) proposes a piecewise linear digital predistortion system and method for temperature compensation of a power amplifier, which test the power amplifier characteristics at different temperature points, fit a relation function between piecewise linear model parameters and temperature, and calculate updated model parameters according to real-time temperature in an actual operation stage, so as to compensate the influence of temperature variation on the power amplifier characteristics. However, the scheme still belongs to a quasi-static temperature compensation mode essentially, the parameter updating depends on a pre-fitted temperature-parameter function relation, a dynamic thermal memory effect caused by rapid transient fluctuation of the chip temperature under a high-power continuous or pulse output working condition cannot be tracked in real time, when the temperature is changed severely, deviation is easy to occur between the pre-fitted relation and the actual nonlinear characteristic of the power amplifier, and a digital predistortion system and a method for a high-efficiency transmitter are disclosed in a patent application document 2 (US 7577211B 2), which adopt a three-way parallel architecture of a linear path, a memoryless predistortion path and a memory-based predistortion path and utilize an IIR filter bank to compensate the higher-order reactive memory effect and the thermal memory effect. However, the model structure of the scheme is fixed, the parameter self-adaptive updating period is long, and when the nonlinear characteristic fast transient drift caused by instantaneous heating of the broadband high-power amplifier is faced, the real-time tracking and the fast parameter updating are difficult to realize. At present, when facing a high-power precise measurement scene, the conventional generalized memory polynomial algorithm has obvious limitations, when a high-power radio-frequency power amplifier outputs continuously or in a burst mode, the chip temperature can quickly rise and severely fluctuate, a strong dynamic thermal memory effect is caused, a nonlinear characteristic curve of the power amplifier can quickly drift along with the temperature, and as the generalized memory polynomial algorithm is required to depend on a huge mathematical model with high-order and deep memory dimensions when fitting broadband cross characteristics, the dimension of an autocorrelation matrix is extremely high, massive high-dimensional matrix inversion operation is required to be performed when predistortion parameters are updated, the extremely high calculation load leads the period of updating the predistortion coefficients of the system to be long, the response speed of the algorithm is far delayed from the speed of temperature drift, the nonlinear mutation caused by instantaneous heating can not be tracked in real time by the quasi-static huge calculation mode, the model weight can not be adjusted in time in the middle and later period of the algorithm, finally the linearization lock loss phenomenon is caused, and the stability and the measurement precision required by a test instrument are extremely high are seriously damaged. Disclosure of Invention The invention aims to overcome the defects of the prior art, and aims to solve the technical problem of slow tracking of dynamic thermal memory effect caused by high calculation load, and provides a broadband power amplifier linearization method based on predistortion. The invention provides a broadband power amplifier linearization method based on predistortion, which comprises the specific process steps of collecting radio frequenc