Nonlinear modeling method for high-field MRI (Magnetic Resonance Imaging) high-power RF (Radio Frequency) power amplifier

Abstract

The invention discloses a nonlinear modeling method for a high-field MRI (Magnetic Resonance Imaging) high-power RF (Radio Frequency) power amplifier. The nonlinear modeling method comprises the steps of: segmenting an acquired original baseband data sequence and distorted baseband data sequence, training a first nonlinear model by using a first segment of original baseband data sequence as input data and using a first segment of distorted baseband data sequence as output data, obtaining model parameters of the first nonlinear model, training a second nonlinear model by using a second segment of original baseband data sequence as input data and using a second segment of distorted baseband data sequence as output data, obtaining model parameters of the second nonlinear model, and giving the model parameters of the first nonlinear model to the first nonlinear model to obtain a first sub-model; giving the model parameters of the second nonlinear model to the second nonlinear model to obtain a second sub-model; and verifying accuracy of the first sub-model and the second sub-model. The nonlinear modeling method has the advantages that a nonlinear model of the high-field MRI high-power RF (Radio Frequency) power amplifier can be accurately established, and nonlinear characteristics of the high-field MRI high-power RF (Radio Frequency) power amplifier are accurately tracked.

Description

technical field [0001] The invention relates to a nonlinear modeling method of a power amplifier, in particular to a nonlinear modeling method of a high-field MRI high-power radio frequency power amplifier. Background technique [0002] High-power RF power amplifiers for high-field MRI, under the action of high-power dynamic range Singer pulse signals, show bifurcations on the AM / AM and AM / PM curves, that is, high-power RF power amplifiers for high-field MRI have large dynamic range bifurcations. linear. Traditional digital predistortion is only suitable for low-power RF power amplifiers in communication systems, and it is difficult to directly apply bifurcation dynamic nonlinear suppression of high-field MRI high-power RF power amplifiers with power up to tens of kilowatts and dynamic range of excitation signal power up to 65dB. In view of this, it is important to design a nonlinear modeling method for high-field MRI high-power RF power amplifiers that can accurately estab...

AI Technical Summary

Problems solved by technology

Traditional digital predistortion is only suitable for low-power RF power amplifiers in communication systems, and it is difficult to directly apply bifurcation dynamic nonlinear suppression of high-field MRI high-power RF power amplifiers with power up to tens of kilowatts and dynamic range of excitation signal power up to 65dB.

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