Accurate large-signal GaAs MESFET and HEMT modeling for power MMIC amplifier design

This article describes, from an industrial user's point of view, how large-signal GaAs MESFET and HEMT modeling can be done accurately and efficiently for power MMIC amplifier design. The method is based on commercially available CAD tools enhanced by in-house software (e.g., small-signal parameter extraction, generation of load-pull contours). The Materka model is shown to predict accurately the large-signal characteristics of GaAs MESFETs, but not of pseudomorphic HEMTs. For these devices, a modified Angelov model is found to be adequate. A method for determining the numerous large-signal model parameters is presented. Model verification is achieved by comparing simulated and on-wafer measured data like static I(V)-characteristics, multiple bias S-parameters, gain compression characteristics, and load-pull contours. Results of device scaling and calculations of optimum load impedances are discussed. The close fit to the measured data proves that an excellent basis for large-signal power MMIC design has been established.     

The AB‐C Doherty power amplifier. Part I: Theory

In this article, the complete theoretical analysis of a Doherty amplifier employing a Class AB bias condition for the Main and a Class C one for the Auxiliary devices, respectively, is presented. Starting from the simplified model of an active device, the analysis of the AB‐C Doherty behavior is carried out as a function of the input signal. In particular, the proposed approach is based on the analysis of the output drain current waveforms generated by the two active devices, while assuming a Tuned Load configuration (i.e., short circuit condition) for higher harmonic terminations. A closed form formulation is derived in order to directly design an AB‐C Doherty amplifier, while fully understanding the basis of its physical behavior. Finally, which Doherty parameters can be chosen by the designer or have to be implicitly fixed are discussed and clarified. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.     

基于ATM89C52的GPS实验装置研制

GPS是具有三维导航与定位能力的卫星导航与定位系统,该文介绍一个以ATM89C52微处理器、GM611鼠标式GPS接收机和液晶模块MGLS-12032A为核心的GPS实验装置,介绍GPS的工作原理及实验装置的硬件组成和软件结构等,此实验装置能满足GPS相关课程的实验教学要求及一般工业项目的需要。     

Dependences in Strategy Logic

Strategy Logic (SL) is a very expressive temporal logic for specifying and verifying properties of multi-agent systems: in SL, one can quantify over strategies, assign them to agents, and express LTL properties of the resulting plays. Such a powerful framework has two drawbacks: first, model checking SL has non-elementary complexity; second, the exact semantics of SL is rather intricate, and may not correspond to what is expected. In this paper, we focus on strategy dependences in SL, by tracking how existentially-quantified strategies in a formula may (or may not) depend on other strategies selected in the formula, revisiting the approach of [Mogavero et al., Reasoning about strategies: On the model-checking problem, 2014]. We explain why elementary dependences, as defined by Mogavero et al., do not exactly capture the intended concept of behavioral strategies. We address this discrepancy by introducing timeline dependences, and exhibit a large fragment of SL for which model checking can be performed in 2-EXPTIME under this new semantics.     

基于SL811HS的数据采集系统的USB主从机双角色设计

介绍USB在数据采集系统中的应用，基于当前USB数据采集系统的一些不足，提出一种同时实现USB主机和设备双角色（DRD）的方案。详细讲述了利用C8051F020和USB双角色器件SL811HS设计USB主机／设备接口，重点分析了如何实现主机／设备模式的转换的方法，并给出了硬件的关键电路和软件结构。     

基于H.26L关键算法模块软件编码器的设计与实现

继制定了H.261、H.263、H.263+等视频压缩标准后,ITU—T正在制定新的视频压缩标准H.26L,目的是为了取得更加有效的图像压缩效果和提供理想的传输接口。文章首先分析了H.26L的各个关键算法模块的原理,与H.263、H.263+进行比较分析,得出其优点;然后阐述如何用VisualC++6.0实现这些算法模块;最后通过实验证明,该文设计的软件编码器能达到更高效的压缩比、信噪比和编码速度,具有一定的实用价值。     

一种生物机器人遥控导航系统

给出了一种生物机器人遥控导航系统,通过刺激大鼠脑部特定部位实现对大鼠的导航控制.系统主要包括:无线参数发射装置和植入式神经刺激系统两部分.发射装置主要由单片机(C8051F330)、无线调频发射芯片(QN8027)和功率放大电路组成,神经刺激系统由单片机(C8051F330)、无线调频接收芯片(QN8025)、模拟开关和植入式电极组成.植入式刺激系统采用表贴原件焊接,体积为20mm×15mm×3mm,质量为6g(含可充电锂电池3g).大鼠内侧前脑束(MFB)区单侧和丘脑腹后外侧核(VPL)左右双侧被选中作为刺激神经位点,每个神经位点植入1对电极.每对电极作为1个通道与神经刺激系统相连,可以通过无线发射装置实时调节每个通道的电流刺激参数.实验结果表明:适当的电流刺激大鼠MFB区可以实现对大鼠的虚拟奖励使之向前行走,适当的电流刺激VPL区可以控制大鼠左转或右转.     

A novel parametric-effect MEMS amplifier

This paper presents the theory and measurements of a mechanical parametric-effect amplifier with a 200-kHz input signal and a 1.84-MHz output signal. The device used is a MEMS time-varying capacitor which is composed of an array of low-stress metallized silicon-nitride diaphragms, and is pumped by a large-signal voltage at 1.64 MHz. This induces a large change in the capacitance, and results in parametric amplification of an input signal at 200 kHz. The parametric amplifier capacitance is 500 pF, resulting in an output impedance of 140 Ω. A higher impedance can also be achieved with a lower capacitance. To our knowledge, this device is the first-ever MEMS mechanical up-converter parametric-effect amplifier developed with an up-conversion ratio of 9:1. The measurements agree very well with theory, including the effect the series resistance and the and of the MEMS time-varying capacitor. The application areas are in amplifiers which operate at very high temperatures (200°C-600°C), under high particle bombardment (nuclear applications), in non-semiconductor-based amplification, and in low-noise systems, since parametric amplifiers do not suffer from thermal, shot, or 1/f noise problems     

Practical optoelectronic neural network realizations based on thefault tolerance of the backpropagation algorithm

This paper describes how the fault tolerance of the backpropagation algorithm can be used to accommodate the realistic (nonideal) transfer characteristics of the optical communication links used, between neural layers, in optoelectronic neural networks. In particular the authors demonstrate that networks, utilizing MSM (metal-semiconductor-metal) photodiodes (PDs) and either LED (light emitting diode) or MQW (multiple quantum well) laser transmitters within these intraneural links, are capable of performing satisfactorily even in the presence of such nonideal device phenomena as: 60% optical crosstalk, 50% optoelectronic device variation, or a thresholded (I(th)=0.5*I(max)) laser output characteristic. Subsequent to this, the authors then show how it is possible to use this fault tolerance to simplify the neuron architecture, to the extent that it consists only of MSM PDs a current amplifier, and an MQW laser. The overall neuron transfer function is then a first-order approximation to the original sigmoidal function.     

ADV611在实时远程监控系统中的应用

介绍了ADV 611芯片的基本原理和功能,探讨了应用ADV 611芯片设计和实现实时远程监控系统的方法。由于ADV 611芯片是基于小波变换理论设计生产的一种视频解压缩芯片,具有大压缩率、高质量的视频压缩率,因此该远程监控系统能够利用低带宽信道进行传输并实现对机房等重点部位的实时监视。     

The AB‐C Doherty power amplifier. Part II: Validation

In part I, the complete theoretical (and nonlinear) analysis of a Doherty amplifier employing a Class AB bias condition for the Main Amplifier and a Class C one for the Auxiliary device has been presented. In this article, the experimental validation of the proposed theory is presented, describing the step‐by‐step procedure to be adopted when designing an AB‐C Doherty. The amplifier was realized at 2.14 GHz in hybrid form using two (0.5 μm, 1 mm gate periphery) GaN HEMTs. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.     

基于小信号S参数的MOSFET射频功率放大器设计

介绍了如何利用场效应管的小信号散射(S)参数设计射频功率放大器,并采用此设计方法,选用场效应管,设计了一种工作在160 MHz频段的金属氧化物半导体场效应管(MOSFET)功率放大器.在工作频段内,功率放大器增益大于23 dB,输入端口的匹配网络的回波损耗S11优于-19 dB.实例证明:该设计方法仿真简单,易于实现,具有重要的工程应用价值.     

Data structures in SL5

The procedural approach to data structures used in the SL5 programming language is described. The SL5 procedure mechanism forms the basis for this approach to data structures by treating procedures and their activation records (environments) as data objects and by decomposing the traditionally atomic operation of procedure invocation into more elementary components. The basic idea is that environments, since they are data objects, can also be used as data structures. The result is a single unified linguistic mechanism for constructing both procedures and data structures. Several examples are given.     

基于S3C2410的Windows CE驱动开发

文中阐述了设备驱动程序的概念和结构,介绍了Windows CE.NET环境下开发驱动程序的特点以及开发中一些常用的工具,对不同工具的开发特性进行了介绍。详细阐述了驱动的系统结构,重点研究了Windows CE.NET环境下的本机驱动和流驱动模型。并以华恒科技的基于Samsung S3C2410的HHARM9-EDU开发板的触摸屏驱动程序为例,对Win-dows CE.NET环境下开发具体驱动程序作了解释。     

深亚微米CMOS运算放大器的综合

利用一种计算电路直流工作点的技术，并采用基于BSIM3v3M OS模型的MOS管评估器来提高基于公式法进行电路综合的精度；同时提出一种综合策略，使得综合后得出的运算放大器在工艺波动和工作条件(如电源电压和温度)变化时，仍能满足性能要求．大量的实验结果表明：文中方法可以快速综合出可制造的深亚微米CMOS运算放大器．     

基于SL811HST和S3C4510B的嵌入式USB主机与设备的设计

本文介绍了基于USB接口芯片SL811HST和ARM微处理器S3C4510B的嵌入式USB主机及设备的设计与实现,详细介绍了Linux平台下主机控制器驱动程序和USB设备固件与驱动程序的设计。文中也简要介绍了USB规范及Linux中的USB子系统。     

Bus and Buffer Usage in In-Home Digital Networks: Applying the Dantzig–Wolfe Decomposition

In an in-home digital network several data streams (audio, video) may run simultaneously over a shared communication device, e.g. a bus. The burstiness of a data stream can be reduced by buffering data at the sending and receiving side, thereby allowing a lower bus share allocation for the stream. In this paper we present an algorithm that determines how much of the bus capacity and buffer space should be allocated to each stream, in order to have a feasible transmission schedule for each stream. Furthermore, the algorithm determines a transmission schedule for each stream, indicating how much data is transmitted over time. We model the problem as a linear program and apply a Dantzig–Wolfe decomposition such that the multiple-stream problem can be solved by repeatedly solving single-stream problems. For these single-stream problems we briefly describe efficient algorithms to solve them.     

基于SOC单片机的频率特性测试仪设计

测量仪器正朝着数字化、智能化、虚拟化方向发展,介绍了利用SOC单片机开发DF4812频率特性测试仪;这是一种用来测量诸如低频放大器、声学器件、各种滤波器及其它有源或无源四端网络的"幅度-频率"特性曲线的虚拟仪器,该仪器由下位机(主机)和上位机(PC机)两大部分组成,通过打印机接口进行通信;重点讨论了系统模拟数字混合(SOC)单片机及编程,系统的外围硬件主要包括信号直接数字合成器(DDS)、大规模可编程逻辑电路(CPLD)、对数放大器等电路;系统经过测试,达到了预期的设计目标,系统产品化后,取得了相当好的经济效益。