新型Hammerstein动态非线性功放模型及其预失真应用

New Hammerstein Dynamic Nonlinear Model of Power Amplifier and Its Pre-distortion Application

针对宽带功放以及高效率功放出现的记忆效应,提出一种改进的Hammerstein动态非线性模型。为提高建模精度,通过主路径和附加路径构建改进的Hammerstein动态非线性模型。主路径使用有限冲激响应滤波器分别构建弱记忆效应子系统和强记忆效应子系统,对这2个子系统分别建模,使用查找表构建无记忆非线性模型。对附加路径建模时,仍采用将记忆线性系统和无记忆非线性系统分别建模的思想。仿真结果表明,改进的Hammerstein模型不仅能补偿短时记忆产生的带内失真,而且抑制了由于长时记忆产生的带外频谱再生,建模精度有了较大程度的提高。

For memory effects occurring in broadband amplifiers and high-efficiency power amplifier,an improved dynamic nonlinear Hammerstein model is presented.In order to improve modeling accuracy,improved dynamic nonlinear Hammerstein model is built by using primary path and additional path.The model uses a Finite Impulse Response（FIR）filters to construct weak and strong memory effects subsystems respectively,and memory effects of the two subsystems are modeled respectively,and using a Lookup Table（LUT）to build nonlinear model without memory effects.The additional path modeling is still using the modeling idea that is modeling linear system memory and non-memory systems respectively.By simulating the test,the improved Hammerstein model not only can compensate dispersion in-band frequency generated by Short Term Memory（STM）,but also can restrain the dispersion out-band low-frequency generated by Long Term Memory（LTM）.Modeling accuracy is greatly improved,and it has very important significance to apply this model to pre-distortion technology.