一种多档位增益滤波器的设计

提出了由AT89C51单片机控制增益和截至频率的低通滤波器设计方案．采用测量放大器和开关电容滤波器构成功能部件，重点讨论了基于开关电容滤波芯片和非易失性数字电位器实现截止频率和增益多档位调节的新方法。     

微机械可变电容制作工艺中的牺牲层释放和残余应力分析

运用高选择比的特别配方来释放MEMS可变电容制作工艺中的牺牲层,以保护上级板金属铝层,同时很好地释放牺牲层磷硅玻璃。探讨了上级板的粘附问题,对工艺中影响成品率的关键因素残余应力进行了模拟,当温度T为350℃时,平面应力P为811.6 MPa;当温度T为500℃时,平面应力P为1 185.9 MPa。分析了残余应力对上级板的影响和对悬臂梁的等效弹性系数的影响。     

电解质对高压(160 V)液体钽电容器电性能的影响

研究了有机物对液钽电容器工作电解质闪火电压及电导率的影响。试验表明,适当的有机物加入工作电解质中,可以吸附在Ta2O5介质膜表面,减少阳极界面处阴离子的有效浓度,使工作电解质闪火电压适当提高。利用所研制的工作电解质浸渍装配成160 V/47μF的液钽电容器,经1 000 h高温负荷实验,测试结果表明电容器电性能良好。     

激光微细熔覆快速原型制备

传统上厚膜电容的制备由于采用了丝网技术、烧结工艺、有限的匹配温度特性材料,使得要实现高容量、低损耗、高频性就必须同时改变材料的成分、制备工艺和技术, 这是无法同时达到的.而采用激光微细熔覆快速原型制造技术,不需要高温烧结和掩模的制备,在不改变电极膜特性的情况下直接制备了适应高容量、低损耗和高频应用的介质膜.同时,消除了原有技术通过多次印刷和增加厚度来减少针孔的弊端,以及高温烧结带来的电极材料和介质材料成分的扩散,利用CAD/CAM系统可灵活地制备所设计的图形和尺寸,实现了元件小型化、轻薄化的制造.     

智能光网络ASON中波长分配算法探讨

WDM网络的高速发展，使得各种路由波长算法（RWA）的研究和应用比较成熟，而随着IP应用的爆炸式增长，ASON技术具有巨大的发展潜力，相对于WDM的RWA算法的研究，ASON中RWA算法的研究有待进一步的细化，本文在WDM网络的波长分配算法的基础上，详细地阐述了波长分配算法在ASON中的要求及改进。     

A Continuous Time Auto-Zero Offset Compensated Switched Capacitor Integrator

A continous mode CMOS switched capacitor integrator with almost zero offset is presented. The offset is compensated using an auto-zero technique and proper circut elements have been used to attenuate disturbances due to charge injection and clock feedthrough. The circuit includes two parallel paths which operate alternately in order to integrate in one path while compensating the offset in the other path. The circuit is capable of removing the offset voltage and its integral, and many other spurious signals at the output. The designed integrator has an initial offset of about –250 V which raises to an amount of about –400 V after one second of integration.     

Influence of electrolyte characteristics on the electrochemical parameters of electrical double layer capacitors

Electrical double layer capacitors based on ideally polarizable nanoporous carbon electrodes in propylene carbonate with the addition of different 1 M Me₃EtNBF₄, Me₂Et₂NBF₄, MeEt₃NBF₄, Et₄NBF₄, Et₃PrNBF₄ and Et₃BuNBF₄ electrolytes have been tested by cyclic voltammetry, chronoamperometry and electrochemical impedance methods. The limits of ideal polarizability, low-frequency limiting capacitance and series resistance, time constant, Ragone plots (energy density vs. power density dependencies) and other characteristics have been discussed. The influence of the electrolyte molar mass on the electrochemical characteristics of the nanoporous carbon electrode cells has been established. The applicability limits of the Srinivasan and Weidner model have been tested.     

A Switched Opamp-Based Bandpass Filter: Design and Implementation in a 0.35 μm CMOS Technology

A fully differential SC bandpass filter (central frequency, 58 kHz; Q = 15; and voltage gain, 8) based on the switched-opamp approach is designed and implemented in this work. The filter operates from a single 1 V supply voltage and is realized in a 0.35 m CMOS technology. It has been characterized with a sampling frequency of 1 MHz and its power consumption is about 230 W. As a main internal filter component, an appropiate switched opamp was also designed. Its common-mode feedback circuit was implemented by using an error amplifier and sampling of the output common-mode voltage is carried out by applying a DC offset to level shift the common-mode sample. It provides an accurate common-mode output for a wide temperature and supply voltage ranges.     

Queueing Dynamics and Maximal Throughput Scheduling in Switched Processing Systems

We study a processing system comprised of parallel queues, whose individual service rates are specified by a global service mode (configuration). The issue is how to switch the system between various possible service modes, so as to maximize its throughput and maintain stability under the most workload-intensive input traffic traces (arrival processes). Stability preserves the job inflow–outflow balance at each queue on the traffic traces. Two key families of service policies are shown to maximize throughput, under the mild condition that traffic traces have long-term average workload rates. In the first family of cone policies, the service mode is chosen based on the system backlog state belonging to a corresponding cone. Two distinct policy classes of that nature are investigated, MaxProduct and FastEmpty. In the second family of batch policies (BatchAdapt), jobs are collectively scheduled over adaptively chosen horizons, according to an asymptotically optimal, robust schedule. The issues of nonpreemptive job processing and non-negligible switching times between service modes are addressed. The analysis is extended to cover feed-forward networks of such processing systems/nodes. The approach taken unifies and generalizes prior studies, by developing a general trace-based modeling framework (sample-path approach) for addressing the queueing stability problem. It treats the queueing structure as a deterministic dynamical system and analyzes directly its evolution trajectories. It does not require any probabilistic superstructure, which is typically used in previous approaches. Probability can be superposed later to address finer performance questions (e.g., delay). The throughput maximization problem is seen to be primarily of structural nature. The developed methodology appears to have broader applicability to other queueing systems.     

多时滞离散切换系统反馈镇定

研究一类具有多时滞子系统的离散切换系统的稳定性分析和反馈镇定问题。通过状态变量的转换，将时滞切换系统变为不含时滞项的切换系统。以LMI形式给出了在任意切换信号作用下多时滞离散切换系统渐近稳定的充分性条件，以及系统状态反馈镇定、输出反馈镇定的控制器设计。并通过两个仿真实例验证所设计控制方案的有效性。