基于半实物仿真的复杂信号生成设计

针对卫星导航系统干扰模拟与抗干扰测试需求,基于半实物仿真原理,提出了一种利用ADS软件和矢量信号发生器产生自定义波形复杂信号的方法。对半实物仿真系统的硬件平台的搭建要点进行了介绍,完成了复杂信号在ADS系统平台下的建模与仿真,阐述了半实物仿真流程。利用矢量信号分析仪89600S对生成的复杂信号进行了测试,并通过与ADS仿真结果的对比分析,验证该方法的可行性。     

多粒度建模方法分析及实例研究

多粒度建模技术己经成为当前分布式仿真技术、基于仿真的采办及动态数据驱动的应用仿真等众多先进仿真技术的理论和应用基础,因此开展多粒度建模的研究对于仿真技术的发展具有重要意义.多粒度建模方法是目前多粒度建模领域的重点研究内容.首先分析比较了三种典型的多粒度建模方法,提出适合复杂系统仿真应用的多粒度建模方法--动态聚合解聚法...     

基于COSIM的定性定量集成建模方法

定性建模技术相比定量建模技术能更加准确地描述复杂系统中的混沌性、不确定性和不可预测性。为全面系统地描述定性定量复杂系统,将定性建模技术跟定量建模技术相结合,提出一种基于多学科虚拟样机建模仿真理论(COSIM)的集成建模方法。在此基础上引入基于置信规则的定性知识和定性接口的描述,提出了集成建模的层次化模型结构的形式化表示方法;同时,基于对仿真系统中定性推理和定量解算的统一调度,给出了一种定性定量协同求解方法,最后,通过对UMl建模语言的扩展,提出了集成建模语言。通过设计并实现鱼雷规避仿真系统,验证了该建模方法的有效性。     

Simulation model framework design for complex communication network of satellite navigation system based on SMP2.0

The complex communication network of satellite navigation system (SNS‐CCN) possesses the characteristics such as large scale, complicated architecture, and integrated satellite earth. Composite modeling and simulation take significant roles in solving large‐scale system simulation issues, as far as one concerned, the solution has not been proposed in the field of SNS‐CCN yet. According to the simulation of information flow for SNS‐CCN, this paper proposes a composite framework of simulation model based on SMP2.0 while applied with combination modeling methods, and then proposes a development and integration method for component structure and simulation service structure, which can support the composite modeling and make appropriate simulation service extensions according to the request. Then, we develop an information flow verification simulation system for SNS‐CCN with the proposed development and integration method of simulation model.     

Practical aspects of complex permittivity reconstruction with neural-network-controlled FDTD modeling of a two-port fixture.

The paper discusses characteristics of a new modeling-based technique for determining dielectric properties of materials. Complex permittivity is found with an optimization algorithm designed to match complex S-parameters obtained from measurements and from 3D FDTD simulation. The method is developed on a two-port (waveguide-type) fixture and deals with complex reflection and transmission characteristics at the frequency of interest. A computational part is constructed as an inverse-RBF-network-based procedure that reconstructs dielectric constant and the loss factor of the sample from the FDTD modeling data sets and the measured reflection and transmission coefficients.As such, it is applicable to samples and cavities of arbitrary configurations provided that the geometry of the experimental setup is adequately represented by the FDTD model. The practical implementation of the method considered in this paper is a section of a WR975 waveguide containing a sample of a liquid in a cylindrical cutout of a rectangular Teflon cup. The method is run in two stages and employs two databases--first, built for a sparse grid on the complex permittivity plane, in order to locate a domain with an anticipated solution and, second, made as a denser grid covering the determined domain, for finding an exact location of the complex permittivity point. Numerical tests demonstrate that the computational part of the method is highly accurate even when the modeling data is represented by relatively small data sets. When working with reflection and transmission coefficients measured in an actual experimental fixture and reconstructing a low dielectric constant and the loss factor the technique may be less accurate. It is shown that the employed neural network is capable of finding complex permittivity of the sample when experimental data on the reflection and transmission coefficients are numerically dispersive (noise-contaminated). A special modeling test is proposed for validating the results; it confirms that the values of complex permittivity for several liquids (including salt water acetone and three types of alcohol) at 915 MHz are reconstructed with satisfactory accuracy.     

逐次截尾样本下电子元件混联系统可靠性指标的EB估计

在逐次截尾样本下,研究电子元件混联系统可靠性指标的估计问题。将Bayes方法和极大似然法相结合,在平方损失下,获得部件失效率、系统可靠度和平均寿命的经验Bayes估计。最后给出随机模拟例子,说明该方法的正确性。结果表明可靠性指标的经验Bayes估计值精度较高。     

Multisim中磁耦合线圈的建模

EDA技术已经广泛地用于电路仿真和设计,Multisim软件因其丰富形象的虚拟器件得到实验仿真使用者的一致青睐。本文针对Multisim9．0以下版本缺少磁耦合线圈元件的缺陷,提出一种建立虚拟磁耦合线圈分析模型的方法,推导了该虚拟器件模型参数与磁耦合线圈参数之问的对应关系,通过与实测数据、PSpicc和Multisim10．0仿真结果进行比较,验证了该模型的正确性。还可以利用该虚拟器件实现基于磁耦合线圈的耦合谐振以及无接触电能传输的实验仿真研究。     

基于传播图论的多链路信道仿真及其在TDOA定位系统性能评估中的应用

为了解决在真实环境下到达时间差(time difference of arrival, TDOA)定位性能评估所面临的测量成本高、不可控干扰因素较多等问题,提出了一种利用传播图论多链路信道仿真来评估TDOA定位系统性能的方法. 即采用传播图论的方法生成不同的信道冲激响应,并通过软件无线电装置产生经信道畸变的射频信号,作为多个TDOA传感器的输入,形成一种新型的TDOA定位检测方法. 首次将复杂外场采用射频仿真的方式,针对城市环境中的TDOA系统构建4个测试场景,对TDOA系统的定位精度进行检验. 仿真结果表明,被测的多链路定位系统在信号带宽不小于200 kHz条件下表现出良好且稳定的性能. 此外,本文提出的嵌入衍射机制的图论建模方法,相比传统图论更为有效地提升了TDOA定位误差的仿真准确度.     

Modeling and analysis of multiconverter DC power electronic systems using the generalized state-space averaging method

This paper presents a modular approach for the modeling and simulation of multiconverter DC power electronic systems based on the generalized state-space averaging method. These systems may consist of many individual converters connected together to form large and complex systems. In addition to simplifying the analysis procedure, by using the proposed method, the time step for analysis of the system can be increased. Therefore, the required computation time and computer memory for complex systems can be reduced considerably. In this paper, after introducing the proposed approach, results of applying the method to a representative system are presented.     

Behavioral Modeling Methods for Switched-Capacitor Σ∆ Modulators

Sigma-delta Modulators (SigmaDeltaMs) are cornerstone elements in oversampled analog-to-digital converters and digital-to-analog converters (DAC). Although transistor-level simulation is the most accurate approach known for these components, this method becomes impractical for complex systems due to its long computational time requirements. Behavioral modeling has become a viable solution to this problem. In this paper, we study styles and issues in the accurate modeling of low-power, high-speed SigmaDeltaMs and introduce two new behavioral models for switched-capacitor (SC) integrators. The first model is based on the SC integrator transient response, including the effects of the amplifier transconductance, output conductance, and the dynamic capacitive loading effect on the settling time. The second model is based on a symbolic node admittance matrix representation of the system. Nonidealities such as jitter, thermal noise, and DAC mismatch are also addressed and included in a dual-band, GSM/WCDMA, second-order, multibit SigmaDeltaM model with individual level averaging. VHDL-AMS and MATLAB Simulink were used as modeling languages. Both models are validated against experimental data, showing competitive results in the signal-to-noise-plus-distortion ratio. A comparative analysis between the proposed and a traditional model is presented, with emphasis on the degrading effects due to the integrator dynamics. Moreover, a general simulation speed analysis of the proposed models is addressed.     

HSpice在电路内部参数容差统计分析中的应用

提出一种基于HSpice的器件内部参数蒙特卡罗统计分析方法对电子电路进行仿真设计。针对PSpice软件只能采用特定库元件进行统计分析的局限性,研究HSpice蒙特卡罗分析的技巧、程序语句参数的设置、输出结果的判读等,解决基于高精度内部参数器件模型的电路性能仿真,给出应用该方法实现电路内部参数蒙特卡罗统计分析的仿真过程。可以有效地提高电路设计的准确性、可靠性和电子产品生产的合格率。实验表明这种方法可以对组成电路器件的任意参数进行蒙特卡罗统计分析,包括MOS管、运放等的模型内部参数,在优化电路设计中具有很高的实用性。     

两维转镜的等效动态控制误差模型辨识

两维转镜的动态控制误差是影响激光制导武器对抗闭环半实物仿真试验精度的重要误差源,建立准确的控制误差模型是系统精度分析的基础。对于转镜的动态控制误差分析建模问题,常采用经典的频域设计法建立控制系统的传递函数来分析其控制误差,建模过程复杂且难以建立准确的模型,提出了一种过程辨识的方法,分析了辨识原理、辨识输入信号设计、模型阶次及模型参数的辨识方法等,在使用行列式比定阶法确定模型阶次的基础上,采用递推最小二乘法建立了转镜的等效动态控制误差模型。然后,根据转镜控制系统指标设计等效正弦信号对该模型进行了验证,结果表明:动态控制误差模型估计输出与实际仿真输出基本相同,估计误差均值为0,最大值仅为13,说明了建模的准确性,同时也为激光制导武器对抗闭环半实物仿真试验系统中其他仿真设备的建模提供了方法支持。     

Finite-Point-Based Transistor Model: A New Approach to Fast Circuit Simulation

In this paper, a new approach of transistor modeling is developed for fast statistical circuit simulation in the presence of variations. For both the I-V and C-V characteristics of a transistor, finite data points are identified based on their physical meanings and their importance in circuit operation. The impact of process and design variations is embedded into these key points using analytical expressions. During the simulation, the entire I -V and C -V curves are interpolated from these points with simple polynomial formulas. This novel approach significantly enhances the simulation speed with sufficient accuracy. The model is implemented in Verilog-A to support generic circuit simulators. The accuracy and convergence of the proposed model are comprehensively evaluated through a set of benchmark circuits, including nand, a pass-gate, latches, AOI, ring oscillators, and an adder. Compared to SPICE simulations with the BSIM models, the simulation time can be reduced by 7 times in transient analysis and more than 9 times in Monte-Carlo simulations.     

Modeling of Irregular Structures in Scene Simulation Based on Creator and 3dsmax

Creating proper 3D models plays an important pole in the development of scene simulation system based on multigen creator and Vega software. However, it is very difficult to construct complex structures by multigen creator. In this paper, an approach is proposed which is utilizing 3dsmax as assistant modeling software. 3D models developed in 3dsmax could be saved in 3ds format and then imported into multigen creator software. The models are revised and then saved in fit format by creator. For reducing model＇s data, simplification strategy is proposed. The problem of constructing complex models in creator is solved smoothly. In the development of digital rocket simulation project, the models constructed by this method have good visual effect, small size, and could be driven by Vega correctly.     

Adaptive Modeling of Analog/RF Circuits for Efficient Fault Response Evaluation

In this paper, we propose a methodology for adaptive modeling of analog/RF circuits. This modeling technique is specifically geared towards evaluating the response of a faulty circuit in terms of its specifications and/or measurements. The goal of this modeling approach is to compute important test metrics, such as fail probability, fault coverage, and/or yield coverage of a given measurement under process variations. Once the models for the faulty and fault-free circuit are generated, we can simply use Monte-Carlo sampling (as opposed to Monte-Carlo simulations) to compute these statistical parameters with high accuracy. We use the error budget that is defined in terms of computing the statistical metrics and the position of the threshold(s) to decide how precisely we need to extract the necessary models. Experiments on LNA and Mixer confirm that the proposed techniques can reduce the number of necessary simulations by factor of 7 respectively, in the computation of the fail probability.     

基于PSPICE进行模拟电路故障建模的方法

文章研究了基于PSPICE的模拟电路故障仿真中的故障建模问题。提出了用故障字典法诊断模拟电路硬故障时,基本元件的物理故障和集成电路的功能故障进行故障建模的方法。在直流诊断和交流诊断中，故障建模的方法有所不同。最后用例子说明了这种方法的可行性。     

Automatic nonlinear auto-tuning method for Hammerstein modeling ofelectrical drives

Accurate modeling of electrical drives for online testing is a relevant problem, because of their nonlinear behavior. Efficient modeling for simulation, performance evaluation, and testing must consider accurate as well as simple models. This paper proposes the application of auto-tune methods to identify equivalent Hammerstein models, where the nonlinear process is approximated by a static nonlinear element followed by a linear dynamic second or third-order model. The effectiveness of the presented procedure is first verified by simulation results, showing that Hammerstein models overcome the limitations inherent to small-signal linearizations. A standard implementation of such technique considers a relay adjustment for attempts in a heuristic way. In this paper, two innovations are proposed: the relay adjustment is automatically shifted and the method is applied for complex electric drives. Experimental results are shown in the case of a drive constituted by a DC/AC inverter supplying a single-phase induction motor and of a step-down chopper     

无刷直流电机双闭环串级控制系统仿真研究

为了有效地分析和设计BLDCM控制系统,基于Matlab提出了一种新型的模块化的BLDCM控制系统仿真建模的方法。对各个模块进行了详细说明。最后,采用经典的速度、电流双闭环控制方法对该建模方法进行了仿真测试。结果表明仿真波形符合理论分析。转速环引入了积分分离的PI调节器使超调量为零,系统特性稳定,它为实际系统设计和调试...