微型电场传感器在工频电场测量中的应用研究

该文基于高性能的MEMS电场敏感芯片研制出一种新型的工频电场测量系统。针对芯片调制被测电场后其输出信号的特征,采用正交相关检测原理提出一种可抑制背景干扰噪声的工频电场解调算法,设计出小型化、空间分辨力高的工频电场测量探头,并在基础上提出MEMS工频电场测量系统的系统级设计方案,成功实现了MEMS电场敏感芯片输出信号的无线采集、滤波、以及电场信号的高精度解调。高压输电线路下工频电场测量结果表明,MEMS工频电场测量系统与传统电场测量仪的测量结果具有良好的一致性。     

基于CPLD和89S51的多功能信号测量仪

提出一种基于CPLD和89S51的多功能信号测量仪,该测量仪可测量频率,周期和脉宽等参数.介绍了高精度测频方法、可编程逻辑器件应用以及周期脉宽测量方法.以CPLD和单片机为核心,消除了直接测频方法对测量频率需采用分段测试的局限性,该多功能信号测量仪可在整个测试频段内保持高精度,测量频率范围达0.1Hz~100MHz以上.     

基于PID控制粉尘浓度测量仪的实现

为了扩大粉尘测量仪的测量范围,采用一种自适应的测量方法,即根据被测环境粉尘的浓度自动调节传感器的接收灵敏度,并结合相应的软件算法,使高、低浓度的粉尘都能得到有效测量。在设计过程中运用PID算法对测量过程进行控制,使测量仪在运行中进行实时调节,以降低测量数据的振荡。通过对烟雾释放出粉尘的浓度测量,运用Matlab对测量数据进行拟舍,得到了平滑的响应曲线。实测结果表明,该方法有效地扩大了测量范围,使测量范围达到了0．01～48mg／m3。     

光调制平衡电光检测

介绍了一种新的电光检测方法 ,即光调制平衡电光检测技术 .它通过调制探测光信号 ,利用差分平衡 ,实现对样品电场的锁相检测 .这种方法不调制被测电信号 ,可彻底消除对被测电场的影响 ,而且方法简单 ,便于操作 .介绍了光调制平衡电光检测系统及检测原理 ,以 Ga P为样品 ,对静态电场进行了模拟测量 .将此方法应用于电光取样技术 ,测量了 Ga As共面波导在频率为 3GHz下的微波信号 .     

光调制平衡电光检测

介绍了一种新的电光检测方法,即光调制平衡电光检测技术.它通过调制探测光信号,利用差分平衡,实现对样品电场的锁相检测.这种方法不调制被测电信号,可彻底消除对被测电场的影响,而且方法简单,便于操作.介绍了光调制平衡电光检测系统及检测原理,以GaP为样品,对静态电场进行了模拟测量.将此方法应用于电光取样技术,测量了GaAs共面波导在频率为3GHz下的微波信号.     

基于MEMS的距离自适应型非接触静电仪

静电场测量是检测物体是否携带过量静电最直接的手段,对于静电防护具有重要意义.传统的静电仪主要依赖固定距离测量,在被测物难以维持静止或不容易靠近时,距离改变引起灵敏度变化,造成测量误差.该文基于微机电系统电场传感器,提出一种可根据测试距离自适应调整灵敏度的静电测量思路:通过超声波模块测量被测物的距离,然后通过单片机查找对应的灵敏度系数,结合电场测试结果计算被测电压.针对研制的静电仪,该文提出基于实验室标定及现场标定相结合的校准方法,搭建了动态灵敏度标定系统,计算出不同测试距离、不同被测物尺寸的传感器灵敏度系数对应关系.与定距测量的传统静电仪相比,该文通过灵敏度动态标定,实现了更精确的非接触表面静电压测量;采用微机电系统电场敏感元件,具有体积小、功耗低、易集成、可批量化制备等优点,封装后无裸露可动部件,可靠性高.经第三方计量检测,在不同测试距离下的平均误差为–2.98％.     

时间间隔测量仪在时延测试中的应用

介绍了用时间间隔测量仪测时延的方法,提出了切实可行的改善时间间隔测量仪测量结果的不确定度的方法,并给出了其在不同测试条件下的测量结果.最后,简单介绍了其在工程测试中的应用.     

智能电阻电容电感测量仪的设计与开发

设计了以单片机MSP430为控制核心的智能电阻电容电感(RLC)测量仪,实现了被测元器件的自动识别及参数测量.系统采用多个继电器,通过切换不同的激励信号得到采样电阻上不同的响应来判别被测器件的属性,通过切换不同的采样电阻来扩大测量范围以及测量精度.系统的显示部分采用128×64点阵式液晶显示屏实时显示被测元器件的属性和实测的值.此系统具有操纵简单和参数测量范围广等特点.     

一种多用智能温度测量仪的设计与实现

设计实现了一种多用智能温度测量仪。采用传感器为DALLAS公司的单总线数字式温度传感器DS18B20及单片机为8051,通过单片机对传感器采集到的数字信号进行计算处理,实现温度的测量、温度数值的数字显示及高温报警等功能。提供了完整的硬件电路图和软件流程图,并详细介绍了软件设计要点及创新点。经实物测试实验,该测量仪既能测量环境温度,又可测量人体温度,具备使用方便、响应快、结果显示直观的特点。     

一种液体密度、高度测量仪设计

本液体密度测试仪以32位单片机STM32F103RC为核心控制器,通过三个气压传感器分别采集玻璃管不同状态的压强,利用控制器对采集的数据进行处理,结合液体压强公式,得到被测液体的密度和高度,并通过OLED液晶显示屏实时显示,对比于已有液体密度测试仪所采用的方法,本密度测量仪具有响应快、直接显示、携带方便等特点。     

基于铁电液晶电控双折射的调谐滤波器的研究

将铁电液晶作为缺陷层引入一维光子晶体中,基于液晶的电控双折射,形成快速窄带调谐滤波器.用传输矩阵法研究了铁电液晶缺陷光子晶体的可调谐滤波特性,计算了电场对滤波器透射峰的位置、强度、个数和带宽的影响,结果表明该滤波器呈现良好的滤波功能.     

Electromagnetic field level temporal variation in urban areas

Temporal variations of electric field levels have been continuously monitored over a period of a week at seven different urban locations and the results are presented and analysed. It has been found that the electric field level exhibits an important random variation with time. From the results analysis, it can be concluded that a single 'snapshot' measurement using a broadband field strength meter could underestimate the maximum averaged values by up to 9 dB. In urban environments, a continuous field meter using a portable datalogger would be required to obtain accurate measurements. Alternatively, compliance with the radiation limits for 99% of the time can be guaranteed from a single 'snapshot' measurement provided that an additional 8 dB margin under the maximum permissible values is considered.     

基于开关电流技术的切比雪夫滤波电路的实现

提出了一种运用开关电流技术实现切比雪夫低通滤波电路的方法。将双二次滤波器的传递函数由s域进双线性z变换,确立了基于开关电流积分器的双二次节电路,利用这种双二次节可以实现开关电流滤波器。文中采用双二次低通滤波器级联实现了六阶切比雪夫低通滤波器的设计与仿真,仿真结果表明切比雪夫低通滤波器的陡峭衰减特性和理想幅频特性符合设计要求,从而证实了该方法的可行性和正确性。     

Electrooptic tunable filters for infrared wavelengths

This paper describes the performance characteristics of an electronically tunable infrared filter based on the electrooptic effect. Like the acoustooptic tunable filter, this device operates by selectively coupling principal polarizations in a birefringent crystal at a Phase-matched wavelength by means of a spatially periodic refractive index perturbation. Instead of a traveling acoustic wave, however, the electrooptic tunable filter employs a temporally static electric field. The main advantages of this filter are its very low power consumption and its versatility of passband programming by virtue of separately addressable voltages under microprocessor control. Two experimental embodiments of the filter are described, one using longitudinal fields, collinear with the light beam, the other using transverse fields in a "thick waveguide" configuration. Experimental results of filter characteristics in the wavelength range2-10 mum are presented. We also present examples of passband synthesis that are achieved by apodizing the amplitude of the applied electric field perturbations. These include passband broadening and sidelobe suppression. The experimental transfer characteristics exhibit good agreement with the theoretical computer plots. Typical driver voltages are ∼ 500 V.     

基于MEMS的距离自适应型非接触静电仪

静电场测量是检测物体是否携带过量静电最直接的手段,对于静电防护具有重要意义。传统的静电仪主要依赖固定距离测量,在被测物难以维持静止或不容易靠近时,距离改变引起灵敏度变化,造成测量误差。该文基于微机电系统电场传感器,提出一种可根据测试距离自适应调整灵敏度的静电测量思路:通过超声波模块测量被测物的距离,然后通过单片机查找对应的灵敏度系数,结合电场测试结果计算被测电压。针对研制的静电仪,该文提出基于实验室标定及现场标定相结合的校准方法,搭建了动态灵敏度标定系统,计算出不同测试距离、不同被测物尺寸的传感器灵敏度系数对应关系。与定距测量的传统静电仪相比,该文通过灵敏度动态标定,实现了更精确的非接触表面静电压测量;采用微机电系统电场敏感元件,具有体积小、功耗低、易集成、可批量化制备等优点,封装后无裸露可动部件,可靠性高。经第三方计量检测,在不同测试距离下的平均误差为–2.98%。     

基于ARM与μC/OS-Ⅱ的弯管流量计的研究与设计

嵌入式技术已经广泛用于工业领域,弯管流量计是工业领域里一种常见的流量计量仪器,文中将ARM与μC/OS-Ⅱ应用于弯管流量计中,利用实时操作系统的任务分配,来扩展弯管流量计的功能设计。实现了无纸记录仪,大容量数据存储转移,网络远程维护等功能。     

电磁兼容抗扰度试验对电能表校准系统防护技术的研究

该文介绍了电能表电磁兼容抗扰度检测,校表系统防护技术,给出了防护方法及原理介绍,为相关的电能表生产企业及电能表检测中心在该领域提供一些技术参考。     

Synthesis of novel all-dielectric grating filters using geneticalgorithms

The feasibility of novel all-dielectric waveguide grating filters is demonstrated, using a genetic algorithm (GA) to solve for material dielectric constants and geometric boundaries separating homogeneous regions of the periodic cell. In particular, the GAs show that simple geometries (not previously reported) utilizing a small number of layers and/or gratings can be found to yield bandpass or stop-band filters with user defined linewidth. The evaluation of the fitness of a candidate design entails the solution of an integral equation for the electric field in the cell using the method of moments (MoM). Our implementation is made efficient by using only very few design frequency points and accurately approximating a given filter transfer function by a quotient of polynomials as a function of frequency. Additionally, the problem impedance matrices are conveniently represented as the product of a material independent matrix and a vector of dielectric constants, thus allowing us to fill the matrices only once. Our code has been parallelized for the Cray T3D to take advantage of the intrinsic parallelization efficiencies offered by the GAs. Solutions are illustrated for a very narrow-band single-grating transmission filter and a relatively broad-band double grating reflection filter. Additionally, a solution for a five homogeneous layers Fabry-Perot filter is also presented     

电能量计量计费小主站系统设计

为了实现发电厂对电能量的自动抄表、计量结算与发电考核等功能,本文介绍了针对电厂厂站的电能量计量计费小主站系统的体系结构以及系统功能实现技术。该系统的数据模型是建立在电力计量对象的基础上,以CJHJ为开发工具,同时采用了C/S＋B/S多层体系结构,在设计模式上采用了先进的MVC设计模式。该系统集数据自动采集、统计、考核于一体,可方便实现与电厂办公自动化系统数据交换。     

Development of the hybrid electric field meter for simultaneous measuring of vertical and horizontal electric fields of the thundercloud

This correspondence presents a development of hybrid electric field meter methodology. This particular field meter can simultaneously measure the vertical and horizontal electric fields of the thundercloud. The additional horizontal electric field provides the useful information of the direction of thunderclouds. The capability of the apparatus was experimentally evaluated and has been confirmed that it has the satisfactory sensitivity to both components of electric field. Additionally, an instance of observation results of the cloud-to-ground and ground-to-cloud lightning discharge has been presented.