CAJ | 학술논문

针对调制气流声源存在较强的谐波畸变，将声源系统等效为 Hammerstein 非线性模型，利用该模型下的预失真技术对声源进行非线性补偿研究。根据辨识的 Hammerstein 模型中静态非线性部分带有直流分量的特点，给出了考虑直流分量补偿的预失真算法，并用数值仿真验证了算法的准确性和直流分量补偿的必要性。在非线性补偿实验中，根据单频信号辨识得到 Hammerstein 模型参数，采用 NFxPEM算法求得对应的预失真 Wiener 模型参数和预失真波形。实验结果表明，与直接发射相比，补偿发射后声波的功率谱中谐波能量有所下降，而基频能量有小幅度的上升，说明了研究思路的正确性。
침대조제기류성원존재교강적해파기변，장성원계통등효위 Hammerstein 비선성모형，이용해모형하적예실진기술대성원진행비선성보상연구。근거변식적 Hammerstein 모형중정태비선성부분대유직류분량적특점，급출료고필직류분량보상적예실진산법，병용수치방진험증료산법적준학성화직류분량보상적필요성。재비선성보상실험중，근거단빈신호변식득도 Hammerstein 모형삼수，채용 NFxPEM산법구득대응적예실진 Wiener 모형삼수화예실진파형。실험결과표명，여직접발사상비，보상발사후성파적공솔보중해파능량유소하강，이기빈능량유소폭도적상승，설명료연구사로적정학성。
Aimed at the harmonic distortion problem in the air-modulated speaker(AMS),the AMS behavioral model was represented by a Hammerstein structure,and the research on predistortion of AMS based on this model was made.As the DC offset exists in the nonlinearity of the Hammerstein model,a predistortion algorithm considering the DC offset compensation was developed.The validity of the algorithm and the necessity of the DC offset compensation were verified by computer simulation.In the experiment,a single sinusoidal excitation signal was first used to identify the Hammerstein model.Then,using the identified system parameters,the NFxPEMalgorithm was performed to obtain the parameters of Wiener predistorter and to predistort the excitation signal.From the experiment results,it is found that our approach is effective in reducing the harmonic power with a relatively small upgrade in the fundamental frequency power.