Dual in-plane electronic speckle pattern interferometry system with electro-optical switching and phase shifting

A dual in-plane electronic speckle pattern interferometry (ESPI) system has been developed for in situ measurements. The optical setup is described here. The system uses an electro-optical switch to change between the illumination directions for x and y sensitivity. The ability of the electro-optic device to change the polarization of the laser light forms the basis of this switch. The electro-optic device is a liquid-crystal layer cemented between two optically flat glass plates. An electric field can be set up across the layer by application of a voltage to electrodes. The speckle interferometry system incorporates two additional liquid-crystal devices to facilitate phase shifting, and the overall system is controlled by advanced software, which allows switching between the two perpendicular planes in quasi real time. The fact that there are no moving parts is an advantage in any ESPI system for which mechanical stability is vital.     

标准表法现场流量校准装置数据采集器的研制

介绍了一种自行研制的标准表法现场流量校准装置的数据采集器,详细阐述了采集器的硬件组成、软件结构及实现的功能.该装置为流量现场校准提供了一种准确、可靠、便捷的校准工具.     

Pid数字化控制在箱式炉中的应用

介绍了采用Pid数字化温度控制仪表及双向可控硅的开关对箱式电阻炉的电气控制系统进行技术改造,整个电气控制系统构成由Pid数字化温度控制系统、箱式炉主电源、超温报警系统以及工作温度时间打印系统等组成。Pid数字化温度控制仪表采用了ALTEC公司PC900型温度智能控制器,阐述了系统功能及工作原理。     

Virtual instrument for instantaneous power measurements

A computer-based data acquisition system coupled by means of a general-purpose instrumentation bus (IEEE488/GPIB) with a digital oscilloscope is used to create a virtual instrument with instantaneous and average power measurement capability. The software signal-processing capability of the data acquisition system was used to compensate instrument measurement deficiencies and to enhance signal capture. The virtual instrument is shown to provide instantaneous, AC, and fitted-power averages and time-based plots of power variations for both linear and nonlinear system responses to external excitation. Data taken on a resistor, capacitors, an AC-to-DC power converter, and a bipolar junction transistor inverter establish a ±3% sensitivity with a 10-μW-100-W range over a 1-Hz-10-MHz frequency span     

基于PCI总线的电子舱信号群高速采集系统

设计并实现了一种基于PCI总线的高速数据采集系统,主要包括模拟输入、信号调理、模数转换、数据传输存储以及计算机接口等部分.此系统可用于对某型号电子舱信号群进行实时高速采集,其性能和指标均满足要求.     

On-line digital measurement for the quality analysis of powersystems under nonsinusoidal conditions

This paper presents a digital instrument for the power quality analysis in systems where voltage or current waveforms are nonsinusoidal. It is based on a C40 DSP and on a special high-speed data acquisition system. The analysis is performed by a recursive algorithm which allows the mutable system properties to be tracked on-line. The paper also goes on to discuss the performance of an instrument prototype, both in terms of accuracy and speed of measurement     

高稳定性大型空气温度校准试验箱的研究

为满足温度采集仪的校准需求,研制了高稳定性大型空气温度校准试验箱。阐述了该试验箱的箱体结构、工作原理。以箱体内传热过程的理论模型为基础,结合Fluent软件进行了数值模拟,分析了试验箱体内温度场以及空气流速场的分布及变化。通过试验证明该试验箱控温精度高、温度波动度小、温场均匀性好,可推广应用。     

Design of a CDMA-based wireless data transmitter for embedded sensing

Machine health monitoring is of critical importance to its safe and reliable operation. The emergence of wireless data transmission techniques has extended the scope of health monitoring to machine components and systems that are difficult to access or not suited for wired sensor data acquisition. This paper presents the design and prototype realization of a digital wireless data transmitter based on the code division multiple access technique. The design provides a generic solution for various applications in electronic instrumentation, measurement, and embedded sensing for machine condition monitoring and health diagnosis.     

LabVIEW在虚拟仪器远程数据采集系统中的应用

针对复杂的测试系统的数据采集方法的局限性，提出了一种基于虚拟仪器的远程数据采集系统的软件设计方法，介绍了网络化虚拟仪器及其软件开发平台LabVIEW。运用LabVIEW开发了用于远程数据采集的虚拟仪器，并阐明了其网络协议、硬件、软件设计原理。利用服务监听机制和datasocket技术，通过局域网开发该虚拟仪器可实现网络测试数据的实时发布与读取。     

野战数字音响系统音质优化设计

野战数字音响系统主要用于在各种复杂条件下的户外使用。该产品主要运用了D类功率放大技术、智能控制技术、触摸操控技术等。经过实验发现,在使用D类功率放大和经数字化处理后的声音在听感上存在生硬的感觉,为改善系统的听感,从产品研制的实际出发,对音频驱动器IRS2092增加了音色补偿电路,结合扬声器选用、滚塑音箱号角曲线设计与声相位的调试来综合提升野战数字音响系统的音质,使其能与传统场馆系统的音质媲美。     

Calibration system for electronic instrument transformers with digital output

A high-accuracy system for calibration of electronic instrument transformers with digital output is described. Its design is based on International Electrotechnical Commission (IEC) standards 61850, 60044-8, and 60044-7. The performance of the calibration system has been evaluated. Its estimated relative uncertainty (2/spl sigma/) is within 40/spl middot/10/sup -6/ in magnitude and within 40 /spl mu/rad in phase.     

汞离子频标数据采集系统的小型化设计

为实现汞离子微波频标电子伺服系统的小型化,设计了一种基于FPGA的汞离子频标数据采集系统。采用宽带、高速、低功耗的微芯片电路模块对离子跃迁谱线的微弱荧光信号进行放大、整形、降噪处理;利用FPGA高速光子计数法对信号进行采集。取代了传统的计算机软件LABVIEW与商用仪器结合的数据采集系统,实现了对离子微波频标物理系统中微弱荧光信号的有效采集。     

A conductive polymer based electronic nose for early detection of Penicillium digitatum in post-harvest oranges

We describe the construction of an electronic nose, comprising four chemiresistive sensors formed by the deposition of thin conductive polymer films onto interdigitated electrodes, attached to a personal computer via a data acquisition board. This e-nose was used to detect biodeterioration of oranges colonized by Penicillium digitatum. Significant responses were obtained after only 24 h of incubation i.e. at an early stage of biodeterioration, enabling remedial measures to be taken in storage facilities and efficiently distinguishing between good and poor quality fruits.The instrument has a very low analysis time of 40 s.     

适用于嵌入式应用的高速信号采集电路

介绍了高速采集电路的一个现场数据采集系统的前端．该采集电路由高速A／D,CPLD及高速存储器构成,类似数字示波器或采样卡,具有高速采样,高速缓存以及完整的触发设置功能,适合采集高速瞬时信号．但与通用信号采集产品不同的是该产品具有开放的总线接口．可直接连接各种单片微机,DPS或微处理器,适用于嵌入式系统的应用场合．描述了该电路的功能和原理,重点讨论“Roll Mode”逻辑及其如何实现对高速瞬时信号的捕获功能．     

一种新的低压无功功率补偿装置放电试验测试仪的研发

随着电气产品的发展,低压无功功率补偿装置标准对装置内电容器放电试验的检测要求越来越高,各检测机构必须配以更先进的检验设备才能为电器企业提供更好的检测服务。本文通过引入虚拟仪器技术,将传感器、电子元件、采集卡、计算机等结合起来设计一套便携式低压无功功率补偿装置放电试验测试仪,实现数据采集、波形分析、参数计算、报表自动生成等功能,满足标准中的试验要求,提高工作效率和检测精度。     

基于虚拟仪器的飞机供电特性参数测试系统的设计

介绍了一种基于虚拟仪器PXI总线的飞机供电特性参数测试系统的设计与实现，在设计该测试系统时采用了符合PXI总线规定的硬件仪器模块，使用图形化编程语言Labview设计了飞机供电特性参数的各种测试算法，实现了多通道同时快速数据采集以及并行同步采集。通过虚拟仪器面板的交互式使用，使界面简单明了、非常便于操作。通过对国产某型飞机供电系统的测试实验。结果表明该系统设计先进、稳定可靠、测试结果达到了要求的精度，对于被测的稳态以及瞬态参数有很好的性能，具有非常广泛的应用前景。     

Software for personal instruments

When a personal computer (PC) is used as the computing system of an intelligent instrument, software devoted to measurement process control and to measurement process outputting can be specially developed to assist the operator throughout the measurement process in a friendly way. When these conditions are met, the intelligent instrument is called a personal instrument (PI). The main features of a PI are discussed, and the requirements for PI software are given. The performance of an original software package for PI is illustrated, showing how all the requirements are satisfied. This software, coupled to a good commercial data acquisition system, features high-precision measurement and a high level of friendliness and can be useful for lab tests and educational purposes. For lab tests, this software is a good basis for an automatic test station with extended help facilities. It ensures better performances than that of a digital scope because it allows dedicated measurement routines to be developed and executed. The software is effective for educational applications, since it allows direct application of all capabilities offered by computers in instrumentation, when associated with suitable A/D (analog/digital) conversion hardware     

能源计量器具识采系统的设计与实现

数显式计量器具识采系统利用自主开发的图形识别数据提取技术,结合现场设备,主动识别计量器具上显示的数字,传送到能耗数据采集终端,是能耗数据实时采集的良好补充。     

远场天线测试系统的研究与实现

针对天线参数测试过程及测试要求,分析天线参数测试中的主要问题,研究实际测试过程中环境因素对天线参数测量结果的影响,提出了一种基于虚拟仪器技术的远场天线性能参数自动测试系统的设计方案,详细阐述了该方案的系统组成部分与工作原理,包括矢量网络分析仪、天线测试转台与吊杆的控制原理以及数据采集的时序设计,结合Matlab实现了对影响因素的误差补偿与天线性能参数的测试计算方法,利用数据库技术实现天线测试数据的存储、读取与报告打印,通过现场测试试验验证了该方案的可靠性与可行性。     

A Web-based electrical and electronics remote wiring and measurement laboratory (RwmLAB) instrument

This paper presents an instrument based on a new architecture called "Remote Wiring and Measurement Laboratory" ( RwmLAB) acting as a local multicircuit board on a common distributed panel on the Internet. Matrix switching, data acquisition, data processing and analysis, and graphical unit interface enabled-devices characterize the RwmLAB. RwmLAB is intended to address real-time remote wiring of electrical and electronic circuits and real data acquisition over the Internet instead of using simulated data. This Web-based instrument allows for flexibility and the spontaneous delivery of laboratory material and ensures a global access to a worldwide audience.