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双语推荐：阻抗测量

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分别采用实地法和虚地法测量电感、电容的阻抗特性,通过分析比较,发现采用实地法测量电感、电容的阻抗特性,所测得的阻抗、阻抗角测量值与理论计算值相比较误差较大;而采用虚地法测量电感、电容的阻抗特性,所测得的阻抗、阻抗角测量值与理论计算值相比较误差较小.
In this paper ,the impedance characteristics of inductance and capacitance are measured respectively by using the methods of the field measurement and the virtual ground measurement .By analysis and comparison , the authors find that the error between the value of the measured impedance and impedance angle and the value of theoretical calculations is great by use of the method of the field measurement , while the corresponding error is small by use of the method of the virtual ground measurement .

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阻抗的测量是交流电路实验的重要测试技术,通过阻抗测量能分析被测电路的等效参数.在生产测量中有专用的阻抗测量仪,但价格昂贵.由PC机结合测试电路组成的虚拟阻抗测量实验系统,具有实用意义.本文介绍一种基于VI复数虚拟阻抗测量实验系统的设计与实现原理.
@@@@It is an important testing technology to measure impedance in AC circuit. We get equivalent parameters of the circuit by measuring impedance. The special purpose impedance analyzer in production testing is very expensive. The virtual impedance testing system which is composed of combining the PC with the testing circuit is possessed of realistic sense. This paper introduced the design and implement theory of virtual impedance measurement experiment system based on VI complex.

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针对目前应用于混凝土阻抗测量的系统结构复杂、测量精度低的问题,基于比例测量和DFT数字解调阻抗测量原理,提出了一种多模式高精度混凝土阻抗测量系统的设计。系统采用高度集成阻抗测量芯片AD5933,并利用MSP430F169单片机作为主控,结合上位机界面,能实现单频、多频阻抗测量,系统体积小、功耗低、结构简单、扩展性强。测试结果表明:系统稳定性强、测量精度高,阻抗测量范围为100Ω～10 MΩ,幅值相对误差小于0.7%,相位绝对误差小于0.8°。
Aiming at the problems of lower measuring accuracy and complexity about impedance measurement system which is applied to the concrete structure , based on the principle of proportion and DFT digital demodu-lation impedance measurement , the paper puts forward a design of multimode high -precision impedance meas-urement system.The system uses a highly integrated chip AD5933 to measure the impedance, and the MSP430 F169 MCU as the master , in combination with PC interface .The system has the function of single fre-quency and multi -frequency impedance measurement , with the characteristics of small size , low power con-sumption , simple structure and strong extensibility .The test results show that the system has high stability and high measurement precision .The range of impedance measurement is from 100Ωto 10 MΩ, relative error of impedance measurement is less than 0.7%, the absolute error of phase is less than 0.8 °.

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交流小电流测量是交流阻抗测量的关键技术之一。分析了交流小电流测量对交流阻抗测量的影响,提出采用数字相敏检波原理测量交流小电流的方法,利用互相关技术有效克服放大器噪声对交流小电流测量的影响,完成了交流阻抗测量的预期功能,达到了预期的效果。
AC weak current measurement is one of the key technologies in AC impedance measure-ment. Effect of the AC weak current measurement to AC impedance measurement is analyzed, the method of using Phase Sensitive Detector ( PSD) to measure the AC weak current is put forwarded, using cross-correlation technique the amplifier noise influence to AC current measurement is conquered, the ex-pected function of AC impedance measurement system is done and the desired accuracy is achieved.

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双端供电系统当线路发生单相接地故障时,由于过渡电阻的存在会造成阻抗测量不准确,引起距离保护的不正确动作。首先运用相量图的方法,定性分析了保护位于送电侧和受电侧时,过渡电阻引起阻抗测量误差的原因;为了减小过渡电阻引起的测量阻抗误差,基于全周傅氏算法提出了利用保护安装处负序电流相位代替故障点处故障电流相位的方法,并通过传统阻抗测量方法的改进,在高阻接地的情况下也能够比较准确地求得测量电抗值。EMTDC仿真表明,与传统的计算方法相比,该算法能有效地减小过渡电阻对测量阻抗的影响,保证测量阻抗的准确性。
When a one-phase ground fault occurs in a double end system,distance protection false operation will result owing to the presence of transitional resistance that brings about inaccurate impedance measurement.First,a qualitative analysis is made of the causes of impedance measuring errors due to transition resistance using the phasor diagram when the protection is at the power transmitting side and the power accepting side.To reduce the errors in measuring impedance due to the transtion resistance,a method of replacing the phase of fault current with the phase of negative current at the bus line is proposed based on the full wave Fourier algorithm.And with the traditional impedance measuring method improved,reactance can be calculated with considerable accuracy even during high resistance grounding.EMTDC simulation shows that this method can effectively reduce the influence of transition resistance on impedance measurement and guarantee the accuracy of impedance measurement.

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阻抗管法法向入射隔声量测试过程中,试样与阻抗管间的密封方式是测量结果的一个重要的影响因素。介绍了阻抗管测量法向入射隔声量的方法,重点介绍在阻抗管中的试样安装和密封方法,通过实施4种不同的密封方法,得出密封效果的排序,对阻抗法测量隔声量的试验实施具有参考价值。
The sealing method of samples is an important factor affecting the measurement results in the measurement of sound transmission loss in the impedance tube. This paper introduces the test method and focuses on the specimen installation and sealing method in the impedance tube. By comparing 4 kinds of sealing methods, the performances of these methods are sorted. It provides reference for measurement of the sound transmission loss.

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为了分析引线间的互感,根据镜像理论建立电流极引线在土壤中的镜像和测量系统模型,计算测试引线间的互感抗;并将现场测得的接地阻抗数据分解为阻性成分和感性成分。计算结果与接地阻抗测量结果的对比显示,引线间互感在接地阻抗测量值中所占比重不容忽视。分析结果表明：确保接地阻抗测量结果的准确性,不仅需要对试验结果进行修正处理,还要在测量时避免电流、电压极引线近距离平行布置。
In order to analyze mutual inductance between the down-leads, based on the mirror im-age theory builds a mirror image and measurement system model of current pole down-leads in the soil, calculates the mutual inductance between the test down-leads, and separates grounding imped-ance measured data of field test into resistance component and inductive component. The comparison of calculation result and measuring result displays that there is a large proportion of the mutual induc-tance between the down-leads in grounding impedance measurement values. The analysis result shows that in order to acquire the veracity of measurement result of grounding impedance, ont only need make the modifying treatment for test result but also need avoid the voltage and current pole down-leads parallel arranging in the test.

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高压直流输电运行于单极大地回路方式时，太阳耀斑活动产生的地磁感应电流会使变压器或保护用电流互感器产生直流偏磁现象。当直流偏磁电流进入交流系统后，阻抗继电器的测量阻抗中会产生一个附加阻抗，使阻抗继电器的测量阻抗变大，从而导致距离保护出现欠范围拒动作。文章建立了相应的输电线路距离保护系统模型，推导出了直流偏磁条件下阻抗继电器测量阻抗表达式，同时为了直观的衡量直流偏磁电流对测量阻抗的影响，定义出了直流偏移系数，通过分析不同直流偏移系数条件下的距离保护动作特性，并利用 PSCAD /EMTDC 仿真软件在不同直流偏移系数条件下进行仿真分析，验证了理论分析的正确性。
When High -voltage direct current(HVDC) project operates in monopolar mode, the ground induced cur-rent(GIC) produced by solar flare activity will cause DC magnetic bias phenomena of transformer or current transform -er for protection.While the direct current flows into the power system , an additional impendence will be produced -shown in the impedance relay measurement , which will expand the impedance measuring value , so as to make the im-pedance relay under -reaching range refuse to operate.A corresponding power transmission line distance protection system model has been established , and the impedance relay measuring impendance expression in DC magnetic bias condition has been deduced.Meanwhile, in order to measure the affect of the DC migration bias on impedance meas -urement intuitively, a concept of DC magnetic coefficient has been put forward .The analysis of the operating charac-teristics of distance protection and the simulations based on PSCAD /EMTDC in different DC coeffi

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介绍了基于AD5933的阻抗检测原理和软硬件实现。系统设计采用阻抗测量芯片AD5933,以低功耗高性能处理器STC89C52单片机作为控制器。该检测仪采用AD5933中的数字频率合成器(DDS)产生激励信号,施加在待测阻抗上,ADC采集相应信号并送到片内DFT模块进行数字处理,测量结果通过I2C送至单片机,再由单片机与计算机上位机通信,计算机显示该阻抗值。该仪器能实现电阻、电容、电感阻抗快速、准确地测量,经实验验证,阻抗幅值和相位测量的相对误差较小,(电阻阻抗平均偏差为0.041 1,相位平均偏差为0.152°)。葡萄糖水溶液浓度与阻抗呈线性相关,相关系数大于0.99。
Impedance detection principle based on the AD5933 and the hardware and software implementation are introduced in this paper. System design uses the AD5933 impedance measurement chip, with a low consumption of high-performance processor STC89C52 MCU as the controller. The detector adopts the AD5933 digital frequency synthesizer (DDS) in the excitation signal is produced, imposed on the impedance under test, the ADC acquisition signal and sent to the corresponding chip DFT digital processing module, measurement results through the I2C sent to the microcontroller, again by the single-chip microcomputer and PC computer communication, the computer shows that the impedance values. At the same time also can according to the relationship of impedance blood flow and blood sugar to further realize the noninvasive detection of blood sugar levels. The instrument can realize the resistor, capacitor, inductance impedance measuring rapidly and accurately, through experimental verify that resistive im

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目的研究生物电阻抗测量系统中电极位置对膀胱尿量信号特征的影响,提高检测过程中信号的敏感度,以帮助尿潴留患者定时排尿。方法健康男性大学生8名,采用双路开关同时采集两路电极位置的信号,分别观察电极在小腹部不同位置及测量电极和刺激电极的相对距离对阻抗变化值△Z和阻抗变化率△Z/Z的影响。结果在使用生物电阻抗技术测量膀胱积尿过程中,生物电阻抗Z呈现变小的趋势,不同的刺激/测量电极位置对应的阻抗变化值△Z和变化率△Z/Z不同。结论肚脐下10cm,正负两个测量电极距肚脐中线均为3 cm的位置,正负两个刺激电极与对应正负两个测量电极间距离均为5 cm的位置为最佳的测量位置,其阻抗变化值△Z达(1.2±0.6)Ω,变化率△Z/Z达8.2%±4.9%。该位置的确定对使用生物电阻抗技术提醒尿潴留患者在恰当的时间排空膀胱具有重要的临床意义。
This paper investigates the effect of electrode position on bladder volume measurement with bioimpedance system which is helpful for the patients with urine retention to micturate. Methods The variation of bioimpedance ΔZ and gradient of bioimpedance ΔZ/Z in eight healthy male students are observed in bladder filling,when the stimulating or measuring electrodes are fixed different positions in abdomen by using a two-way switch.Results During the measurement of bladder filling,there is a decrease trend for bioimpedance Z.The variation and gradient of bioimpedance are different with the different electrode positions.Conclusions The optimal location is:1 0 cm under navel,the measuring electrodes both are 3 cm to navel’s midcourt line,and the distance between stimulating and measuring electrodes both are 5 cm.In this electrode location,the variation (ΔZ ) of bioimpedance is up to (1.2 ±0.6 ) ohm,and the gradient of bioimpedance (ΔZ/Z ) is up to 8.2% ±4.9%.The location is i

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