微分方程的VHDL-AMS建模和仿真

讨论了VHDL-AMS的基本语法,给出了其建模仿真微分方程的方法,结合传输线的模型,重点分析了VHDL-AMS不直接支持的偏微分方程转化成常微分方程的建模仿真方法。     

Theoretical design for 120 GHz semiconductor junction circulators: effects of different numbers of terms in the Green's function

A theoretical analysis of the predicted performance and field distributions for semiconductor junction circulators is based on Bosma's Green's function approach which involves a summation of infinite series in the mathematical derivation. The effects are considered of taking a different number of terms in the series, looking at three different circulators centred at 120 GHz. The narrowband semiconductor circulators show a similar effect to the ferrite junction circulator because the field distributions inside the semiconductor discs can be approximated by only considering the dominant modes. However, there is no dominant mode in the broadband circulator and the higher order modes play an important role in the operation of this circulator. In order to obtain a precise representation of the circulation effects inside both narrowband and broadband circulators, at least up to the 6th term, or 18 terms in all, are required to be added in the summation of Green's functions.     

∑-△ A/D转换器混合电路建模方法研究

由于具有转换精度高和其他一系列优点，∑-△过采样A／D转换技术近年来颇受重视，而模拟和混合信号系统的硬件描述语言VHDL-AMS为其提供了一种良好的设计方法。本文根据∑-△ A／D转换器的原理，建立了一个包括二阶∑-△调制器和抽取滤波器的转换器VHDL-AMS模型，同时结合Szermer提出的模型，对两种结构进行了仿真、比较和分析。     

A New Synchronization Algorithm for VHDL-AMS Simulation

VHDL－AMS is the Analog and Mixed-Signal Extensions to VHDL.The paper gives a brief overview of the added features to VHDL.A mixed-signal simulator has been developed based on VHDL-AMS.A new synchronization algorithm is adopted in the simulator.Using the new algorithm the analog kernel does not need to synchronize the digital kernel at each digital event time point.The effciency of the new synchronization algorthm is tested by examples.Simulation results show the newly developed algorithm can speed up the simulation.     

汽车电子点火系统的VHDL-AMS模型

以一个基本的汽车电子点火系统为基础，在研究其工作原理的基础上，对各模块进行行为特征提取，用IEEE标准的数／模混合信号硬件描述语言VHDL－AMS为其建立了行为级模型，仿真结果表明，该系统模型经充实后可以作为研究汽车电子点火系统的仿真模型。     

Polymer Electrolyte Fuel Cell Stack Modelling in VHDL-AMS Language with Temporal and EIS Experimental Validations

This paper deals with two basic issues of fuel cell research： modelling and experimental validation. In particular, the EIS （electrochemical impedance spectroscopy） technique is applied to a PEMFC （proton exchange membrane fuel cell）. Experiments have been performed using a low-cost test bench and instrumentation developed around a 1,200 W Ballard Nexa fuel cell system. An electrical and dynamic model in VHDL-AMS language for PEM fuel cell stack is described. The privileged approach in this paper is an electrical method. Few papers deal with the modelling of a fuel cell in VHDL-AMS language with an electric approach. The fuel cell is characterised cell wise in VHDL-AMS; AC and DC measurements show the good agreement between the simulation results of the model and those measured in experiments. The model is capable to predict accurate stack profiles. The model is validated using temporal and impedance spectroscopy method; the impedance spectroscopy is performed at low and high frequencies. The experimental and simulated Nyquist plots show that the frequency response of the fuel cell stack can be predicted by the proposed fuel cell stack model. At high frequencies, comparisons between experimental and model impedance results are performed and show some similarities between the two Nyquist. Error between the two approaches is below 1.5%.     

模拟／混合信号硬件描述语言VHDL—AMS综述

介绍了VHDL-AMS（VHDL1076.1)——一种完全集成的混合信号设计语言,针对该语言的要素进行了探讨,通过描述该语言的理论基础、混合建模语言和应用范围等,阐述了VHDL-AMS硬件描述语言在模拟和数字混合信号领域应用中的必要性及其优点等。