Boost变换器跨周期调制(PSM)的状态空间平均模型

基于Boost变换器,利用状态空间平均法对跨周调制(Pulse Skipping Modulation,PSM)进行建模和特性分析,推导出电感电流连续(CCM)和电感电流断续(DCM)时系统变压比,调制度M与负载的关系及系统转换效率的理想化公式,得到PSM具有轻载下高转换效率的结论,并设计具有PSM调制特性的控制电路,给出仿真结果。     

变频和脉冲跳变双模式控制电荷泵的建模和实现

提出了一种高性能电荷泵的建模和设计实现方法.为了实现在大的负载电流变化范围内具有高转换效率和低输出电压纹波,提出了变频模式(VFM)和脉冲跳变模式(PSM)双模式控制的电荷泵,并建立了相应的数学模型以方便设计参数的分析和选取.芯片采用TSMC0.35 μm标准CMOS数模混合工艺进行设计制造,总面积约为1.4 mm×1.5 mm.测试结果表明,所设计的电荷泵在全负载电流范围内(5 ～ 100 mA)能够实现双模式的自动切换,取得较低电压纹波和较高效率,达到了设计预期,从而验证了变频和脉冲跳变双模式控制电荷泵的可行性.     

车载数据总线的仿真与建模

文章给出了车载数据总线的模型,车载系统内部广义总线进行了分类研究．并对几种常用数据总线的物理特性及传输特性进行了详细分析。分析了车载数据总线的组成,对多种商用电场仿真软件作比较。最后利用FEKO软件对数据总线进行仿真计算,结合总线特征及软件的应用特点对总线进行了合理的建模简化,分析不同线长,线间距,距地高度的干扰情况,得出了实用的结论。     

高斯白噪声信道中MQAM误码性能——移动通信中多电平正交振幅调制方案的优化考虑(一)

对白噪声信道中MPSK、矩形星座图MQAM与圆形星座图MQAM的传输误码性能作了详细的分析比较,给出相应的误码率计算公式与计算机数值分析结果,为MQAM调制方案的选择提供了理论分析依据。     

脉冲序列的快速搜索法及可信度分析

对于周期脉冲序列的信号分选识别，可采用序列搜索的时域方法[1，2]。本文将大周期内完全重复的脉冲序列分解为多个“单周期信号”．并把它们均定义为周期性信号．同时，提出了序列搜索的一种软件实现方法及密集视频脉冲信号分选的变步长、信步长快速搜索法．在此基础上，本文针对序列搜索分选法的可信度计算公式进行了推导和分析，证实了这种方法的可行性和有效性．     

Modeling and experimental analysis of an antagonistic energy conversion using dielectric electro-active polymers

Dielectric Electro Active Polymers (DEAP) have shown potential features to be applied into the wave energy harvesting purpose. However, current studies of DEAP in generator mode have not sufficiently provided perfect solutions for practical applications. This paper gives a detailed analysis on an antagonistic energy converter (AEC) using two DEAP generators for wave energy application. Firstly, an accurate model of conventional DEAP generator is investigated and compared with that of Neo-Hookean model. Then, the new AEC structure, which consists of two DEAPs in antagonistic connection mode to increase the harvested energy, is introduced. Elastic forces in relaxation phase of one DEAPs are employed to stretch the remained DEAP. Consequently, the required input mechanical energy for each DEAP in AEC is lower than one of conventional DEAP generator. A physical model DEAP generator is also developed for practical operating conditions. Here, electromechanical model of proposed structure is investigated to analyze the performance of the proposed structure. Finally, experiments have been carried out to investigate the performance of the AEC and energy conversion processes. Favorable results e.g. the good agreement between experiments and the modeling results, significant higher energy harvesting efficiency, compact design, and smoother output energy waveforms show great potential to apply the new AEC in real wave energy application.     

行波管放大器相位噪声的分析及其抑制

主要分析规则调相信号对行波管放大器频谱纯度的影响,并且根据行波管放大器相位噪声产生的过程和原因,提出两种抑制相位噪声的方法.     

布里渊光时域反射计中电光调制器的调制特性与控制

在布里渊光时域反射计（BOTDR）中,电光调制器（EOM）的工作点会随着外部环境变化而发生漂移,这将影响BOTDR系统的测量精度及测量稳定性。本文在分析BOTDR系统中EOM调制特性的基础上,提出了一种控制EOM工作点的方法,使用数字信号处理器作为控制核心,采用＂步进跟随＂的算法。实验结果表明,本文方法可以使EOM长期稳定在高微波调制效率的工作点上。将这种方法应用于BOTDR系统中,可以使BOTDR系统的测量精度以及测量稳定性得到提升。     

砷化镓衬底上螺旋电感的建模和分析

针对砷化镓(GaAs)衬底上螺旋电感提出了一种改进形式的集总参数等效电路模型,该等效电路模型能很好地表征螺旋电感的高频效应.同时,应用电磁场全波分析方法对螺旋电感进行仿真,并分析各参数对电感性能的影响.从得到的散射参数中提取出有效电感、Q值和自谐振频率.基于参数优化方法提取等效电路模型中各元件值,并利用曲线拟合技术给出其相应的闭合表达式.这些表达式可用于射频和微波集成电路的设计,从而提高电路设计的性能和效率.     

Analytical modelling and software implementation of synthetic aperture radars

Synthetic aperture radar (SAR) imaging systems are a complement to passive remote sensing. However, the process of image formation is so complex that the final image in the system is formed only after three basic steps: raw data acquisition, forming the signal and the image space. In addition, there are various factors that are involved in the information recorded by SAR within the system and outside the system, such as radar, platform, processing algorithm, imaging region and channel. Each of these factors has been formed by many parameters and this issue adds to the complexity of the behaviour of SAR. Therefore, due to the complexity, providing a model that describes how the SAR imaging system works is highly important. In this paper, the performance of SAR in the image formation section is analytically modelled at first, and then implemented as software. Raw data acquisition is performed in CST software and the signal and image formation are performed in MATLAB software. This implementation provides many abilities, such as better interpretation of SAR images, simulating the effect of the important parameters in SAR images, etc.