设计并仿真实现了一款高线性、高效率Doherty功率放大器,该功率放大器工作频率为3.35 GHz。为了提高Doherty功率放大器的线性度,本文所设计Doherty功率放大器充分利用了载波功放和峰值功放的三阶交调分量(IM3)相互抵消的原理来提高功率...设计并仿真实现了一款高线性、高效率Doherty功率放大器,该功率放大器工作频率为3.35 GHz。为了提高Doherty功率放大器的线性度,本文所设计Doherty功率放大器充分利用了载波功放和峰值功放的三阶交调分量(IM3)相互抵消的原理来提高功率放大器的线性度。本文设计采用两枚Cree公司生产的6 W Ga N HEMT晶体管CGH40006P进行仿真验证,仿真结果证明:在所设计频率点3.35 GHz,IM3<-30 d Bc。展开更多
随着通信技术的发展,行波管预失真电路的研究变得越来越重要。该文针对基于肖特基二极管的非线性发生器,首次分析了二极管SPICE(Simulation Program with Integrated Circuit Emphasis)模型参数中零偏压结电容和串联电阻对预失真扩张曲...随着通信技术的发展,行波管预失真电路的研究变得越来越重要。该文针对基于肖特基二极管的非线性发生器,首次分析了二极管SPICE(Simulation Program with Integrated Circuit Emphasis)模型参数中零偏压结电容和串联电阻对预失真扩张曲线的影响。对目前的微带预失真电路工作在K波段以下,绝对或相对带宽一般不超过1.8 GHz和4%,需在输入及输出端加隔离器等不足,基于ADS(Advanced Design System)软件设计并加工了一种用于中心频率30 GHz,绝对和相对带宽为2 GHz和6.67%的毫米波行波管的微带预失真电路。分别测试行波管和级联线性化器后的行波管,29 GHz,30 GHz和31 GHz的增益和相位压缩量分别可以从7.5 d B和40?,7.3 d B和50?,7.1 d B和59?改善到3.8 d B和10?,3.7 d B和12?,2.4 d B和15?以内。双音测试结果表明,为了达到通信中载波与三阶交叉调制分量抑制比(C/IM3)25 d Bc的要求,单独行波管在29 GHz,30 GHz和31 GHz时需分别回退17 d B,18 d B和18 d B,而加入线性化器后的行波管,只需分别回退12 d B,9 d B和8 d B,也即加线性化器可改善5 d B,9 d B和10 d B,极大地提升了行波管的线性度,具有重要工程应用价值。展开更多
A new method of 360° turning 3D shape measurement in which light sectioning and phase shifting techniques are both used is presented in this paper.A sine light field is applied in the projected light stripe,meanw...A new method of 360° turning 3D shape measurement in which light sectioning and phase shifting techniques are both used is presented in this paper.A sine light field is applied in the projected light stripe,meanwhile phase shifting technique is used to calculate phase of the light slit.Thereafter wrapped phase distribution of the slit is formed and the unwrapping process will be made by means of the height information based on the light sectioning method.Therefore phase measuring results with better precision can be obtained.At last the target 3D shape data can be produced according to geometric relationships between phases and the object heights.The principles of this method are discussed in detail and experimental results are shown in this paper.展开更多
We investigate some probabilistic properties of a new class of nonlinear time series models. A sufficient condition for the existence of a unique causal, strictly and weakly stationary solution is derived. To understa...We investigate some probabilistic properties of a new class of nonlinear time series models. A sufficient condition for the existence of a unique causal, strictly and weakly stationary solution is derived. To understand the proposed models better, we further discuss the moment structure and obtain some Yule-Walker difference equations for the second and third order cumulants, which can also be used for identification purpose. A sufficient condition for invertibility is also provided.展开更多
文摘设计并仿真实现了一款高线性、高效率Doherty功率放大器,该功率放大器工作频率为3.35 GHz。为了提高Doherty功率放大器的线性度,本文所设计Doherty功率放大器充分利用了载波功放和峰值功放的三阶交调分量(IM3)相互抵消的原理来提高功率放大器的线性度。本文设计采用两枚Cree公司生产的6 W Ga N HEMT晶体管CGH40006P进行仿真验证,仿真结果证明:在所设计频率点3.35 GHz,IM3<-30 d Bc。
文摘随着通信技术的发展,行波管预失真电路的研究变得越来越重要。该文针对基于肖特基二极管的非线性发生器,首次分析了二极管SPICE(Simulation Program with Integrated Circuit Emphasis)模型参数中零偏压结电容和串联电阻对预失真扩张曲线的影响。对目前的微带预失真电路工作在K波段以下,绝对或相对带宽一般不超过1.8 GHz和4%,需在输入及输出端加隔离器等不足,基于ADS(Advanced Design System)软件设计并加工了一种用于中心频率30 GHz,绝对和相对带宽为2 GHz和6.67%的毫米波行波管的微带预失真电路。分别测试行波管和级联线性化器后的行波管,29 GHz,30 GHz和31 GHz的增益和相位压缩量分别可以从7.5 d B和40?,7.3 d B和50?,7.1 d B和59?改善到3.8 d B和10?,3.7 d B和12?,2.4 d B和15?以内。双音测试结果表明,为了达到通信中载波与三阶交叉调制分量抑制比(C/IM3)25 d Bc的要求,单独行波管在29 GHz,30 GHz和31 GHz时需分别回退17 d B,18 d B和18 d B,而加入线性化器后的行波管,只需分别回退12 d B,9 d B和8 d B,也即加线性化器可改善5 d B,9 d B和10 d B,极大地提升了行波管的线性度,具有重要工程应用价值。
文摘A new method of 360° turning 3D shape measurement in which light sectioning and phase shifting techniques are both used is presented in this paper.A sine light field is applied in the projected light stripe,meanwhile phase shifting technique is used to calculate phase of the light slit.Thereafter wrapped phase distribution of the slit is formed and the unwrapping process will be made by means of the height information based on the light sectioning method.Therefore phase measuring results with better precision can be obtained.At last the target 3D shape data can be produced according to geometric relationships between phases and the object heights.The principles of this method are discussed in detail and experimental results are shown in this paper.
基金supported by the Fundamental Research Funds for the Central Universities of China (Grant No. 2010121005)supported by the Scientific Research and Development Funds for Youth of Fujian University of Technology of China (Grant No. GY-Z09081)
文摘We investigate some probabilistic properties of a new class of nonlinear time series models. A sufficient condition for the existence of a unique causal, strictly and weakly stationary solution is derived. To understand the proposed models better, we further discuss the moment structure and obtain some Yule-Walker difference equations for the second and third order cumulants, which can also be used for identification purpose. A sufficient condition for invertibility is also provided.
