SILAS: a knowledge-based simulation assistant

A knowledge-based shell for circuit simulation has been developed as a part of a design environment for analog circuits. This shell offers circuit-specific simulation support exploiting expert knowledge for dealing with problems like test function generation and simulation clustering. Furthermore, it provides worst-case analysis capabilities as well as automatic documentation facilities like data sheet generation and a design database. The prototype implementation, SILAS, has been realized as an expert system with blackboard architecture. Knowledge and knowledge execution are strictly separated to allow an easy extension of the incorporated knowledge bases. SILAS is organized as a simulation assistant, which means the user may specify a specific task by a work plan while the task organization and control are taken over by the system. Application areas are all domains which require automated circuit characterization such as synthesis or cell library maintenance     

A Fast Windowing-Based Technique Exploiting Spline Functions for Designing Modulated Filter Banks

A very fast technique to design prototype filters for modulated filter banks without using time-consuming multivariable optimization is introduced. In the proposed method, the prototype filter is optimized by using the windowing technique, with the novelty of exploiting spline functions in the transition band of the ideal filter, instead of using the conventional brick-wall filter. A study of the optimization techniques and three different objective functions existing in the literature has been carried out, and more suitable redefinitions of these objective functions are employed to achieve as optimized prototype filters as possible. The resulting filter banks closely satisfy the perfect reconstruction property, as is illustrated by means of examples.      

An Investigation on Design and Switching Dynamics of a Voltage Source Inverter to Compensate Unbalanced and Nonlinear Loads

In this paper, design aspects of various passive components and switching dynamics of a voltage source inverter (VSI) for compensating unbalanced and nonlinear load are presented. The design method for VSI to track desired reference currents smoothly, is illustrated. By using the proposed method, it is possible to design the passive components of different VSI topologies used for load compensation. The results are supported by detailed simulation studies on a three-phase four-wire compensated system using PSCAD 4.2.1. The design steps are also verified by conducting experiments using a prototype model developed in the laboratory.      

虚拟样机在电子结构设计中的应用

本文介绍了虚拟样机在电子结构设计中的应用,通过对某型号产品的外观仿真、人体工程仿真、热设计仿真,提供了虚拟样机技术在产品设计中的实例,为实现同类电子结构的虚拟样机提供了完整思路.     

基于QPSO优化算法的余弦调制滤波器组设计

提出了一种新的余弦调制滤波器组设计方法,此方法以原型滤波器的阻带衰减作为目标函数,用改进型量子粒子群算法(QPSO)设计最接近满足重构条件的原型低通滤波器,然后在此基础上通过余弦调制得到分析滤波器组和综合滤波器组.实验仿真结果表明,用此方法设计的余弦调制滤波器组(CMFB)具有良好的阻带衰减特性和精确重构性能,在满足性...     

Design verification and testing of power supply system by using virtual prototype

This paper proposes a simulation approach to verify and test power supply system by using a virtual prototype before the hardware prototyping in a single simulation environment. By applying the proposed methodology, the designer can use the virtual prototype effectively by keeping a short simulation CPU time as well as catching most of the design problems.     

Numerical and experimental study of the region of period-oneoperation of a PWM boost converter

A study is presented of a DC-DC boost converter whose output voltage is controlled by naturally sampled constant-frequency PWM operating in both continuous and discontinuous mode. For certain values of the circuit parameters, instability occurs. Moreover, nonlinearities may produce bifurcations and chaos when parameters are varied. The goal of this paper is to delimit in the parameter space the region of period-one operation of the converter which is of practical interest for engineering design. Linear analysis and other conventional methods are sometimes not strong enough to delimit this region, and one must rely on experimental results and careful numerical simulation. The regions are located using two different methods: a prototype which allows variation of all circuit parameters is built up and the results are checked by means of special-purpose C-code simulations, resulting in a good agreement with the experiments. Some families of curves characterize the operational regions, which border on quasiperiodic and subharmonic behavior; these bifurcation phenomena may be related to resonances and to the change of conduction mode     

网络变换在滤波器设计中的应用

介绍了基于耦合原型参数的滤波器设计方法,并以双谐振子为例讲述了网络变换在滤波电路设计中的应用.最终通过引入有限感值变压器模型对整个电路进行了CAD仿真及优化设计,完成了电路制作并给出了结果.     

Parameter optimization and simulated performance of a DVB-T digitaltelevision broadcasting system

A prototype of a digital television terrestrial broadcasting system has been implemented according to the European DVB-T standard. The first step in the construction of this prototype involved parameter optimization via simulation. This paper presents the optimization process of the system parameters and the final achieved BER performance. Important design aspects such as interleaving, convolutional puncturing codes, Viterbi decoding, pilot-based channel correction and optimal pilot power are considered. The DVB-T standard offers some suggested values of the C/N ratio needed to achieve the desired BER requirements in the receiver. However, they have been obtained assuming ideal channel correction and synchronization. Simulation results are provided here in non-ideal conditions     

Electrical design inspection: a methodology for using circuitsimulation in the design and development of electronic power supplies

The authors present an electrical design inspection (EDI) methodology that combines advanced power circuit simulation techniques and RISC (reduced instruction set computing) workstation hardware to use simulation in the day-to-day design of electronic power supplies. This methodology makes use of circuit simulation to detect design faults in electronic power supplies and prevent them from propagating further in the product realization process. A hierarchy of inspections which form the basis of EDI methodology, is introduced. The methodology has been embedded in a prototype electrical design inspection system which has been tested on a Sun Sparcserver 4/490 dedicated to circuit simulation. The power of this methodology has been illustrated by its application to a self-oscillating variable-frequency DC-DC power converter with peak current control. It is demonstrated that EDIS can automatically execute inspections requiring an accurate determination of the steady-state solution of the circuit, and process these results. The steady-state accelerator capability within the SIMPLIS circuit simulator has made it possible to achieve this in an unprecedentedly short CPU time     

雷达电讯虚拟样机构建与仿真技术研究

基于模型的系统工程(MBSE)是工业4. 0 的核心特征之一。借鉴MBSE 的思想,给出了雷达研发全流程中不同形态的电讯虚拟样机的内涵、作用和模型。提出了支持概念样机、功能样机和工程样机的协同仿真平台架构,研究了多领域专业仿真方法以及模型开发和管理两项关键技术。以机载火控雷达功能样机为例,形象展示了虚拟样机的建模、仿真与评估方法。基于虚拟样机的建模、仿真与虚拟验证手段将是复杂电子系统研制的新模式。     

A design of a simple structure switched-capacitor filter based on the concept of the bilinear transformation

A design procedure of the SCF based on the concept of the bilinear transformation is proposed. The final SCF structure is the same as that obtained by the LDI transformation, which means a structure simpler than the usual SCF obtained by the bilinear transformation and which requires no sample-and-hold circuits at the front and back of it when it is employed with the prefilter and the postfilter as the analog filter. The filter response does not suffer from the effect of the inexact simulation of the terminated resistance of the prototype LC filter which appears in the SCF realization based on the LDI transformation and the aperture effect is compensated. The filter performance realized by the proposed design procedure is tested by an experimental circuit with discrete elements.     

基于快速控制原型的ABS实验台控制系统

针对ABS实验台控制器的设计与开发，利用Matlab/Simulink建立ABS实验台控制模型，并进行离线仿真得到理论制动曲线。基于dSPACE的快速控制原型半实物仿真实验设计，在RTI实时接口中将控制模型下载到Autobox中，并在实验管理软件Controldesk中设定数据及进行实验。实验结果表明，所设计的ABS控制器得到的控制效果和离线仿真结果基本一致，验证了控制器的可行性。快速控制原型的方法为控制器的开发提供了一种新思路，减少了开发周期，节约了开发成本。     

Quick simulation: a review of importance sampling techniques incommunications systems

Importance sampling (IS) is a simulation technique which aims to reduce the variance (or other cost function) of a given simulation estimator. In communication systems, this usually, but not always, means attempting to reduce the variance of the bit error rate (BER) estimator. By reducing the variance, IS estimators can achieve a given precision from shorter simulation runs; hence the term “quick simulation.” The idea behind IS is that certain values of the input random variables in a simulation have more impact on the parameter being estimated than others. If these “important” values are emphasized by sampling more frequently, then the estimator variance can be reduced. Hence, the basic methodology in IS is to choose a distribution which encourages the important values. This use of a “biased” distribution will, of course, result in a biased estimator if applied directly in the simulation. However, there is a simple procedure whereby the simulation outputs are weighted to correct for the use of the biased distribution, and this ensures that the new IS estimator is unbiased. Hence, the “art” of designing quick simulations via IS is entirely dependent on the choice of biased distribution. Over the last 50 years, IS techniques have flourished, but it is only in the last decade that coherent design methods have emerged. The outcome of these developments is that at the expense of increasing technical content, modern techniques can offer substantial run-time saving for a very broad range of problems. We present a comprehensive history and survey of IS methods. In addition, we offer a guide to the strengths and weaknesses of the techniques, and hence indicate which techniques are suitable for various types of communications systems. We stress that simple approaches can still yield useful savings, and so the simulation practitioner as well as the technical researcher should consider IS as a possible simulation tool     

The Open-Ring Line: A Low-Loss Surface Waveguide

This paper presents the theoretical analysis of the electromagnetic properties of the open-ring line by means of the Hankel transform. Fields components, stored energy, power flow, dispersion relation, and energy distribution are calculated. Measurements have corroborated our theoretical results. These results help in the design of low-loss line operating in the fundamental dipolar hybrid mode. The measured attenuation on a prototype line consisting of equally spaced aluminum rings held by a metal rod is less than 5 dB/km below 1.8 GHz. Among the possible applications are railway traffic control and railway obstacle detection.     

多路宽带带状线功率分配器设计分析

宽带功率分配器是电子系统的重要部件。提出了宽带带状线功率分配器的设计方案,详细论述了二功分器、八功分器的设计方法,研究了该方法在工程中存在的问题及解决办法。应用电路与电磁场仿真软件进行了仿真,制作了一个3～10 GHz的功率分配器样件,对样件进行了指标测试,详细分析了测试结果与仿真结果存在差异的原因。     

The PAPIA system

In 1983 an Italian research program was begun for the design, simulation and construction of a multiprocessor image processing system. After a first phase devoted to the comparison of suggested and existing systems and to the definition of a set of benchmarks, a new system was defined. The structure of this new system is introduced here: it is based on a fine-grained pyramid of processors built up by means of a pyramidal cell implemented on a VLSI multiprocessor chip. The peculiarities and the capabilities of the processing element are highlighted. The complete hardware and software system has been fully designed and is described. A first working prototype has been built and is now operational.     

The PAPIA system

In 1983 an Italian research program was begun for the design, simulation and construction of a multiprocessor image processing system. After a first phase devoted to the comparison of suggested and existing systems and to the definition of a set of benchmarks, a new system was defined. The structure of this new system is introduced here: it is based on a fine-grained pyramid of processors built up by means of a pyramidal cell implemented on a VLSI multiprocessor chip. The peculiarities and the capabilities of the processing element are highlighted. The complete hardware and software system has been fully designed and is described. A first working prototype has been built and is now operational.     

A simulation-optimization system for the optimal design of amultilevel inverter

In this paper, a simulation-optimization system for the optimal design of a multilevel inverter is presented. This system is a combination of an optimization tool and a simulation program. The optimization tool is used as a powerful procedure for the resolution of the design problem formulated in terms of objective function and constraints. The simulation program is with knowledge of the sequences of operation and is used to compute the inverter steady-state characteristics. An optimal design of the multilevel inverter is performed with the simulation-optimization system. The design constraints include the maximum current ripple in the inductors, maximum voltage ripple in the capacitors, output power and required efficiency of the inverter. The total weight of the capacitors and the inductors is taken as an objective function to be optimized. The optimal design results of the multilevel inverter are verified by an experimental prototype. The inverter is designed and implemented for a UPS application     

Evolutionary Design of Digital Filters With Application to Subband Coding and Data Transmission

In this paper, two evolutionary programming (EP) algorithms (classical EP and fast EP) are applied to design prototype lowpass Finite Impulse Response filters for use in a modulated filterbank. The chosen filter design technique is based on frequency-sampling (where the Fourier transform magnitudes of the filter are the objective variables). Design is simplified by constraining most of these values, leaving only a small number of values in the filter transition band to be optimized. The EP algorithms were used to determine the optimum values for this subset of values. Since there is an additional monotonic constraint on the transition band values, a modification to the EP algorithms was developed called variable limits evolutionary programming. Results indicate that a) both EP algorithms were insensitive to initial conditions, and reliably found the minimum values of the chosen objective functions, and b) the designed prototype filters are suitable to obtain near-perfect reconstruction filter banks, offering quality parameters comparable or better than systems obtained using other techniques