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针对目前传统使用的阻抗测量仪通道少、精度低、操作复杂等诸多缺点,研制了一款测量阻抗范围0~10MΩ、支持USB总线的全自动多通道阻抗测量仪;系统采用STM32F103C8T6处理器为控制核心,高精度阻抗转换芯片AD5933为测量核心,通过上位机设置AD5933配置参数即可完成多通道的单频、多频自动化测量,阻抗数据经USB总线传输至上位机存储及图形方式显示;结果表明该测量仪电路集成度高,操作简单,而且测量相对误差小于1%,性能稳定可靠。 相似文献
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本文介绍了基于C Sharp的锂电池阻抗谱测量系统设计,该系统主要由PC机、ARM、直接数字频率合成器(DDS)、AD5933、信号调理电路等模块构成。该系统经过校准后,通过对两种阻抗模型的测量和分析,其结果表明该系统的测量精度在3.5%以内。最后,测得了HL-18650M锂电池在充满电时10mHz至100KHz频带的阻抗谱。较之传统分立方式的锂电池电化学阻抗谱测量系统,该系统具有体积小、集成度高、成本低、精度较高的突出优点,有利于锂电池阻抗谱测量系统的大规模生产与应用。 相似文献
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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。 相似文献
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生物电阻抗法(BIA)是一种安全非侵入式的、结果可靠有效的人体组成成分(脂肪含量)测量方法;以此为原理,设计了一款便携式无线人体脂肪率测量仪;硬件上,系统以高集成化、低功耗的阻抗测量芯片AD5933为核心,通过蓝牙实现与上位机的无线通信,大大降低了设备的复杂度;软件部分提出一种单频点小阻抗范围的增益系数校准方式,计算量小且容易实现;将新测量仪和欧姆龙体脂仪HBF-358进行对比实验,并作Bland-Altman一致性分析;结果表明,二者的相关系数为0.997;此外,该测量仪还具有易操作、小型化的特点。 相似文献
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《微型机与应用》2014,(15):92-94
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。 相似文献
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This paper presents an adaptive impedance control strategy for flexible manipulators by using an end-effector trajectory control approach. The impedance control objective is converted into tracking a trajectory generated by a designed ideal impedance model. A manifold is designed to prescribe desirable performance of the system. An adaptive control scheme is derived in such that the motion of the system will converge and remain to the ideal manifold for the case of parametric uncertainties. Stability of the control system is analyzed. Simulations are carried out to demonstrate the effectiveness of the proposed control method. 相似文献
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A modeling technique of a subway network is performed in order to quantify the effect of insulated negative current rail on resonance frequencies. A DC track circuit is modeled by means of transmission line modeling (TLM) approach to perform line current and voltage calculation. Impedance and admittance required by TLM equations are first derived. System impedance is expressed in terms of internal and external impedance. The former is calculated using exact expression of a cylindrical conductor whereas the external impedance is taken as the sum of conductor's reactance considering a perfect conducting plane and the ground impedance. The well-known Carson's formulas for ground impedance are compared to Sunde's one to investigate frequency range applicability of the former. Simulations reveal that Carson's expressions are valid for frequencies up to 50 kHz. It appears, however, that using Cason's formulas for higher frequencies lead to underrating ground impedance. To investigate the accuracy impact of internal impedance, ground impedance and inductance on resonance frequencies, a sensitivity analysis is performed. A noticeable resonance effect is observed at 8 kHz for a 10 km length rail. Simulation results show the network impedance effect on track current and voltage. 相似文献
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Stephen E. Sussman‐Fort 《国际射频与微波计算机辅助工程杂志》2006,16(2):135-142
Non‐Foster synthesis bypasses the gain‐bandwidth limitations of conventional LC matching and achieves superior broadband performance by employing negative circuit elements, which are realized via negative impedance converters. The idea is to construct a negative‐image model of an antenna, which cancels the antenna's parasitic reactance and transforms its frequency‐dependent radiation resistance to a constant value. Successful implementation of negative‐image modeling requires the realization of stable, low‐loss negative elements. After a discussion of the basic ideas of non‐Foster matching, we present experimental results for broadband, stable, high‐Q, grounded negative capacitance. Next, in the first experimental confirmation of non‐Foster impedance matching for signal reception, we use a floating negative capacitor to cancel a substantial portion of the reactance of a 6‐in. monopole antenna. Over 20–110 MHz, the signal‐to‐noise ratio improved by up to 6 dB as compared to the same antenna with no matching, or to a lossy‐matched blade antenna of twice the size. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006. 相似文献