直线法中几个问题的讨论

直线法是近几年来引入电磁理论的重要方法。本文着重讨论了直线法中两种不同的引入方法，即求解差分方程的方法和正交变换法之间的一致性，从而可以在正交变换法中奶方便地引用差分方程的研究成果，此外，也论述了直线法与谱域法的关系，从而可以为进一步认识两种方法的实质以及它们之间的互相借鉴提供参考。在此基础上，文章还提出了若干新的想法。     

电路理论中的回路法和节点法的改进及应用

对电路理论中的回路法和节点法进行了改进。应用改进后的方法可以快速准确地解决电路问题，同时一系列复杂问题如自电阻(电导)、互电阻(电导)和其正负符号无需考虑，另外本方法还大大扩展了解题范围，这些优点可以从给出的例子中体现出来。     

宽带天线阻抗匹配网络设计中的实频法

本文对宽带天线阻抗匹配网络设计中的实地与驻波比法进行了理论分析与实验研究，证明 尖法的优越性。用实频法设计的集总参数网络可以有效地解决短波，超短波通信天线的宽带匹配问题。     

模型法与分离塞入比法的改进

本文介绍了模型法与分离塞入比法由于采用了模拟电路，而具有的缺点。提出了改进模型法与改进分离塞入比法，可以利用全数字电路实现。同时，文章分析了改进模型法与改进分离塞入比法的性能，以说明它们克服了原方法的不足，而又保持了原方法的优良性能，并给出了对比实验结果。     

大尺寸椭圆柱面聚光腔的镗削加工法

对椭圆方程中任一点P用解析法求出它的法距和次法距后，可以采用镗削法加工出高精度的椭圆柱面。     

基于最小二乘法的DLT摄像机定标法

摄像机定标是图象处理中的一个关键步骤。DLT（直接线性变换法）是一种简单快速的摄像机定标方法，可以应用在许多场合。文章叙述了DLT的原理，并给出了基于最小二乘法的计算过程。     

浅谈经济分析中的预测方法

阐述了通信工程设计中经济分析方面涉及的几种预测方法。通过预测可以对某一地区的月收入、话务量、用户发展等情况的作一个估计，对工程建设起到一定的指导作用。常用的预测方法大致有数学模型推算法、经验判断法、实际调查法和模拟比照法。     

数字电视接收器自动测试中的丢帧法

为实现输出图像质量判定自动化，提出了丢帧法，该方法具有能自动化、与马赛克捕捉法一致、易实现的特性。对用丢帧法判定的原理、必要性、可行性及其实现做了分析，并就实际应用的效果做了描述，经过测试，证明丢帧法是可以实用的。     

双因素法矩阵预测存在的问题及其解决方法

文章讨论了双因素法矩阵预测的原理和存在的问题，说明采用“强迫置1法”可以克服双因素法的主要弱点，收到良好的效果。     

倒装芯片凸点制作方法

倒装芯片技术正得到广泛应用，凸点形成是其工艺过程的关键。介绍了现有的凸点制作方法，包括蒸发沉积、印刷、电镀、微球法、黏点转移法、SB2－Jet法、金属液滴喷射法等。每种方法都各有其优缺点，适用于不同的工艺要求。可以看到要使倒装芯片技术得到更广泛的应用，选择合适的凸点制作方法是极为重要的。     

Improvement of Power Supply Rejection Ratio in Wheatstone-bridge based piezoresistive MEMS

This paper deals with the design of MEMS-based sensors with piezoresistive transduction. It is demonstrated that when the sensor topology does not allow a perfect matching of resistances in the conditioning circuit (typically a Wheatstone bridge), the resolution of the system is limited by the ability to reject power supply noise. As this ability increases when the output offset of the bridge decreases, the proposed architecture implements a feedback loop to control MOS transistors inserted in the Wheatstone bridge to compensate resistor mismatches. This zero-offset bridge exhibits a very good offset cancellation and therefore a better resolution.     

MEMS压阻式三轴加速度传感器的双路循环电桥检测法

A cycle bridge detection method, which uses a piezoresistive triaxial accelerometer, has been described innovatively. This method just uses eight resistors to form a cycle detection bridge, which can detect the signal of the three directions for real time. It breaks the law of the ordinary independent Wheatstone bridge detection method, which uses at least 12 resistors and each four resistors connected as a Wheatstone bridge to detect the output signal from a specific direction. In order to verify the feasibility of this method, the modeling and simulating of the sensor structure have been conducted by ANSYS, then the dual cycle bridge detection method and independent Wheatstone bridge detection method are compared, the result shows that the former method can improve the sensitivity of the sensor effectively. The sensitivity of the x, y-axis used in the former method is two times that of the sensor used in the latter method, and the sensitivity of the z-axis is four times. At the same time, it can also reduce the cross-axis coupling degree of the sensor used in the dual cycle bridge detection method. In addition, a signal amplifier circuit and adder circuit have been provided, Finally, the test result of the ＂eight-beams/mass＂ triaxial accelerometer, which is based on the dual cycle bridge detection method and the related circuits, have been provided. The results of the test and the theoretical analysis are consistent, on the whole.     

NASA's Anderson Loop

The Anderson loop is a simply implemented measurement circuit topology that uses active subtraction instead of the passive subtraction accomplished by the classic Wheatstone bridge. Larger, inherently linear signals from sensing-element impedance change are available with less excitation power and without the use of transmitters to achieve immunity to wire-resistance variations. Transducers can be designed with any convenient quantity of sensor elements. Transducer intelligence can be implemented within the signal conditioner. The change in a single sensing element can be used in several simultaneous measurements. Sensor elements can appear to have any desired impedance level and influence on any of several outputs     

微流控惠斯通电桥式通用流阻测量方法

标准化是微流控系统的发展趋势,很多器件需要精确的流量控制和传输。因此,准确地表征和测量芯片功能模块的流体阻力具有重要的应用价值。提出了一种类比于惠斯通电桥测量不同流阻大小的器件,该器件将一个芯片内的膜阀视为可变流阻器,与待测器件并联。通过施加不同的压力,控制膜阀的开口度,保持桥平衡,直接计算获得待测芯片的流阻大小。仿真计算发现,其测量范围达到4个数量级,误差控制在3%以内。结果表明,微流控惠斯通电桥是测量流阻的有效方法,可以根据不同的应用环境,设计不同的尺寸和结构,以满足特定需要。     

提高电感传感器测量灵敏度的方法

电感位移传感器被广泛应用于微小位移量检测中,但在一些工程中现有传感器的测量精度和灵敏度达不到测量要求。针对这一问题,对传感器前段信号处理电路进行改进,在传感器上下线圈并联电容形成LC电路,利用LC电路谐振效应改善电路的性能,以提高信号源头的灵敏度;采用Multisim软件对半桥和全桥电路在并联不同大小的电容后的性能进行仿真,并用Matlab对生成的曲线进行最小二乘拟合,比较得出使电路性能最优的电容值和并联方法。结果表明在损失微小线性度的情况下可将灵敏度提高一倍。     

自举式三相半桥级联型多电平逆变器

本文提出了一种新型的三相四线制多电平逆变器,它在常规六开关三相全桥逆变输出上,再级联一级半桥,并加入自举电路,负载中线与输入电源正极相连.在纹波跟踪分段式SPWM(Sinusoidal Pulse Width Modulation)调制下,级联的半桥电能由自举电路工作时得到.该电路拓扑结构及其控制方法,减少了多电平逆变的独立直流电源数,提高了逆变输出电压.文章用逐段计算法分析了规则采样SPWM调制法的自举电容的纹波和电流,以及产生的谐波.通过分析和实验表明,自举电容的电容量、充电回路电阻、负载和调制度等,均对自举电容的纹波和电流有影响.     

Comparing Through-Silicon-Via (TSV) Void/Pinhole Defect Self-Test Methods

Three methods have been proposed to test Through-Silicon-Vias (TSV) electrically prior to 3D integration. These test methods are (1) sense amplification; (2) leakage current monitor; and (3) capacitance bridge methods. These tests are aimed at detecting one or both of two failure types, pin-holes and voids. The test circuits measure capacitance and leakage current of the TSVs, and generate a 1 bit pass/fail signal. The outputs are streamed out through a scan chain. The test time is 10 μs for the leakage test and the sense amplification methods, and is 15 μs for the capacitive bridge method. All these methods can be implemented for test-before-stacking, which will increase assembled yield. Resolution, power and area of these TSV test circuits were compared. The performance of each circuit was studied at PVT corners. The IMEC TSV technology was assumed, and the designs were simulated using the 32 nm predicted device model. Without any failure, the TSV capacitance’s mean value is 37 fF, and its leakage resistance is higher than 850 MΩ. With respect to 37 fF standard capacitance, resolution for the sense amplification method is 3.3 fF (8.9%); it is 0.16 fF (0.4%) for the capacitance bridge method. Although the capacitance bridge method has relatively better resolution, it takes 4x area and 10x power than the other two, and is also more sensitive to PVT variation. Resolution of the leakage current monitor method is 10 MΩ (1.1%) with respect to its threshold 850 MΩ, and use 42.5aJ power in normal case. Sense amplification circuit can be modified to detect equivalent leakage resistance under 2KΩ.     

基于广电业务特征的虚拟货币系统设计与实现

本文对虚拟货币的产生及形成进行了分析研究,阐述了广电行业虚拟货币系统建设的必要性和迫切性,并基于广电行业特征深入分析了虚拟货币系统建设思路及关键技术。同时,本文还重点介绍了基于广电业务特色的虚拟货币系统设计原理、系统架构、技术实现以及系统性能评估,以期通过探索实践,科学合理地设计和建设具有广电特色的虚拟货币系统,助力广电网络转型升级。     

A Time-Constant Calibrated Phase-Locked Loop With a Fast-Locked Time

A time-constant calibrated phase-locked loop with a fast-locked time is presented. A variable capacitance multiplier (VCM) is developed to adjust the equivalent capacitance in the loop filter. And a calibration circuit is used to allow the time constant of the loop filter to track with the reference clock. By using the proposed time-constant calibration circuit and the VCM, the fast acquisition time is achieved and the loop capacitance is also multiplied. A prototype has been fabricated in a 0.35-mum CMOS process to demonstrate the proposed circuit     

Polyconductor beam power sensor

The design is presented of a sensor circuit for the thermal detection and power measurement of incident microwave and laser beams due to accidental or targeted exposure. In this sensor, a polyconductor device acts as a microwave or optical beam absorber. The basic feature of the polyconductor is that its terminal resistance in the transition region can vary by many orders of magnitude with small changes in excitation temperature, regardless of frequency. Thus the heating effect of the incident wave changes the terminal resistance which is converted into a sensitive imbalance of a Wheatstone bridge circuit with appropriate display. This circuit is significantly improved with the aid of an ambient temperature compensation section and a feedback loop to maintain operation in the most sensitive region of the polyconductor characteristic. The sensor has proved to be adequate for a wide range of fluctuations in ambient temperature and incident power levels. Also, since the polyconductor film does not absorb any significant power beyond the transition region, it is found adequate for protecting itself and the circuit connected to it or whatever is immediately behind it, under conditions of relatively large incident beam power. This is attractive for a variety of applications in biomedical engineering as well as in the areas of electronic and laser warfare.