基于SOLT校准技术的S参数测量不确定度评定

目前,常用的S参数测量不确定度评定方法中均未考虑S参数相关性的问题,论文给出了一种2GHz~18GHz频率范围内S参数测量不确定度的评定方法,该方法从校准件的定义出发,基于SOLT校准技术对矢量网络分析仪进行自校准,将校准件引入的不确定度通过矢量网络分析仪传递给被测件(DUT),通过使用蒙特卡洛仿真的方法(MCM)得到矢量网络分析仪测量DUT S参数的测量不确定度,评定过程中考虑了相关性问题,提高了S参数测量不确定度的可靠性和合理性。     

基于 SOLT 校准技术的S参数测量不确定度评定磁

目前,常用的 S 参数测量不确定度评定方法中均未考虑 S 参数相关性的问题,论文给出了一种2GHz ～18GHz 频率范围内 S 参数测量不确定度的评定方法,该方法从校准件的定义出发,基于 SOLT 校准技术对矢量网络分析仪进行自校准,将校准件引入的不确定度通过矢量网络分析仪传递给被测件（DUT ）,通过使用蒙特卡洛仿真的方法（MCM ）得到矢量网络分析仪测量 DUT S 参数的测量不确定度,评定过程中考虑了相关性问题,提高了 S 参数测量不确定度的可靠性和合理性。     

直流数字电流表测量不确定度评估

文章主要依据JJG598-1989《直流数字电流表检定规程》和CNAS-CL07:《测量不确定度的要求》(2011年第二次修订)研究测量不确定度在校准数字万用表过程中的应用。通过设计评定实验,建立数学模型,分析不确定度来源对校准直流电流参数不确定度进行完整的评估。     

电线电缆电阻率测量不确定度评定

电阻率是电线电缆的一个重要性能指标,准确测量电阻率对判断电线电缆的质量状况十分重要,在生产企业及质检部门对电线电缆产品质量检验中是一个重要检验项目。因此,对电线电缆电阻率的测量的准确度要求很高,为了更好的把握测量准确程度,本文介绍了电阻率测量的不确定度评定。     

压力测量不确定度评定基础知识讲座(三) 第三讲 测量不确定度评定方法

本节介绍在测量不确定度评定中所用到的主要方法。不确定度依据其评定方法可以分为"A","B"两类,它们与过去"随机误差"与"系统误差"的分类之间不存在简单的对应关系。"随机"与"系统"表示误差的两种不同的性质;"A"类与"B"类表示不确定度的     

压力测量不确定度评定基础知识讲座(一)第一讲测量不确定度基本概念

本讲介绍与压力测量过程密切相关的一些基本概念. (1)量值. 一般由一个数乘以测量单位所表示的特定量的大小.量值是量的表示形式.通常任何可测的量都是由数值和计量单位组合而成,如105Pa,760 mmHg,30 psi等压力的量值.应当区分数值与量值.数值是数,它是量值的组成部分,如105,760,30是数值,它们不包含计量单位,故非量值;而Pa,mmHg,psi为计量单位.应当指出:数值大的不一定量值大,数值小的也不一定量值小.     

航空发动机矢量推力测量系统的静态校准及不确定度评定方法研究

介绍了航空发动机矢量推力测量系统的静态校准原理,建立了静态校准的数学模型,并通过多元回归分析方法得到了各阶模型的校准系数.在此基础上,针对目前矢量推力测量系统缺少精度评定规范的问题,提出了一种基于校准系数误差传递的不确定度评定方法,并与传统的校准残余误差方法和验证残余误差方法进行了比较.校准实验结果表明,由于加载条件不...     

关于分析评定零件测量不确定度的探讨

测量不确定度作为一个新的概念逐步引入测量结果当中．容易与原先测量结果的测量误差产生混淆。本文通过介绍测量不确定度的概念、评定方法．探讨对零件几何量测量的不确定度评定的方法。     

微波功率敏感器校准系统不确定度分析

文中介绍了微波功率敏感器校准系统的组成,详细阐述了单定向耦合器法校准功率敏感器的原理,对该校准系统测量不确定度的主要来源进行了分析,并结合实际给出了测量不确定度的评定过程。     

基于Crystal Ball软件对测量不确定度的评定

本文首先介绍了测量不确定度的概念,接着阐述了测量不确定度在实验室检测过程中的作用,然后介绍了测量不确定度的方法和步骤,本文介绍了使用Crystal Ball利用蒙特卡罗方法在测量不确定度的应用的步骤,通过软件的使用可以解决在测试实际工作中评定测量不确定度遇到的困难。     

自复位式大电流热保护器测试装置

论文开发了一种热保护器性能检测装置。装置利用霍尔传感器检测电流的大小,控制大功率MOSFET的通断,从而精确测试0～200A热保护器的闭合持续时间,并在人机界面及现场仪表上显示测试结果。     

飞参系统专用地面检测设备校准装置设计

为实现对飞参系统专用地面检测设备的计量和校准工作,采用对各种信号进行自动采集、分析、处理和判断技术,完成飞参系统专用地面检测设备校准装置硬件和软件设计,成功解决了目前国内飞参系统专用地面检测设备校准周期长、效率低、测量数据可靠性差、仪器系统缺乏全面计量保障的状况,实现了对飞参系统专用地面检测设备的计量校准.实际应用表明,该校准装置整个校准过程的自动化程度很高,改变了传统的手工校准方式,缩短了校准周期,提高了校准效率和校准结果的准确性和可靠性,应用前景较好,经济效益明显.     

脉搏波分析用多路正弦恒流源设计

介绍了一种用于脉搏波分析的多路正弦恒流源系统设计方案。该系统主要由PC机用户接口程序、单片机控制电路、DDS正弦波生成电路、滤波器、数字幅度控制电路以及电压-电流转换电路组成。PC机用户程序通过RS232接口与总控AVR单片机通信;总控AVR单片机通过TWI(Two Wire Interface)总线与下位单片机通信。该系统实现了多路正弦恒流源的生成与控制。     

On the use of calibration sensors in source localization using TDOA and FDOA measurements

The accuracy of a source location estimate is very sensitive to the presence of the random noise in the known sensor positions. This paper investigates the use of calibration sensors, each of which is capable of broadcasting calibration signals to other sensors as well as receiving the signals from the source and other calibration sensors, to reduce the loss in the source localization accuracy due to uncertainties in sensor positions. We begin the study with deriving the Cramer–Rao lower bound (CRLB) for source localization using time difference of arrival (TDOA) and frequency difference of arrival (FDOA) measurements when a single calibration sensor is available. The obtained CRLB result is then extended to the more general case with multiple calibration sensors. The performance improvement due to the use of calibration sensors is established analytically. We then propose a closed-form algorithm that can explore efficiently the calibration sensors to improve the source localization accuracy when the sensor positions are subject to random errors. We prove analytically that the newly developed localization method attains the CRLB accuracy under some mild approximations. Simulations verify the theoretical developments.     

不确定未知界的相似组合系统分散自适应输出反馈控制

研究一类具有加性振动的不确定相似组合大系统的分散自适应输出反馈镇定问题,给出了该系统输出反馈镇定的条件。受控系统的不确定项可以是非线性的或时变的,输入通道不确定性满足一般限制,系统的不确定项的界是存在的但却是未知的。所设计的确定性非线性控制器能保证受控系统渐近收敛于系统的平衡点,并且自适应律保持有界。最后进行了仿真研究,表明所得结论是正确脯效的。     

基于FPGA的秒表检定仪的设计

针对秒表检定规程已经更新和检定仪携带不便的问题,提出了一种基于FPGA的秒表检定仪设计方法。首先,该秒表检定仪的设计方法采用Verilog硬件描述语言,以QuartusⅡ为设计平台,采用模块化设计,利用FPGA的高时间精度,数码管驱动电路精准地动态显示计时结果,并且创新性地采用电/机转换装置为撞表机构,更精准地触发秒表,提高了检测被检秒表的准确性。其次,该秒表检定仪采用模块化设计,主要由分频模块、功能控制模块、计时模块、时间设置模块、位置设置模块、显示控制模块、舵机控制模块组成。系统采用自上而下的模块设计方法,并且本设计具有外围电路少、集成度高、可靠度强等优点。实验结果表明,该秒表检定仪测试数据时间精度高,能很好地检测秒表的计时准确性,并且携带非常方便。     

A sensorless PMSM drive using modified high-frequency test pulse sequences for the purpose of a discrete-time current controller with fixed sampling frequency

For electrical machines, accurate position estimations at low speed can be obtained from current responses on high-frequency voltage test pulses. Nevertheless, to apply these voltage test pulses the current controller is often interrupted. In this paper, a modified test pulse sequence is discussed for which the current can be controlled without interruption. To generate the modified test pulse sequence, an asymmetric pulse-width modulator is required. The improvement in the dynamic behaviour of the sensorless drive is discussed by simulations including a salient-pole permanent-magnet synchronous machine, the current control loop, the pulse-width modulator and the position estimator.     

Joint direction of arrival estimation and array calibration for coprime MIMO radar

Compared to large-scale MIMO radar, coprime MIMO radar can achieve approximate estimation performance with reduced antenna number. In this paper, joint direction of arrival (DOA) estimation and array calibration for coprime multiple-input multiple-output (MIMO) radar is considered, and an iterative method for the estimations of DOA and array gain-phase errors is proposed. Based on the received data structure of coprime MIMO radar, trilinear decomposition is firstly adopted to obtain the estimations of transmit and receive direction matrices, which are perturbated by the gain-phase errors. Through equation transformation, the un-perturbated direction matrices and gain-phase errors can be iteratively updated based on Least squares (LS). Finally, the unique DOA estimation is determined from the intersection of transmit and receive direction matrices. The proposed algorithm achieves better DOA estimation and array calibration performance than other methods including estimation of signal parameters via rotational invariance techniques (ESPRIT)-like algorithm, multiple signal classification (MUSIC)-like algorithm and joint angle and array gain-phase error estimation (JAAGE) method, and it performs close to the method with ideal arrays. Multiple simulation results verify the algorithmic effectiveness of the proposed method.     

一种基于脉冲耦合神经网络的语音情感识别新方法

针对汉语语音情感识别问题,提出了一种基于脉冲耦合神经网络(PCNN)的识别方法。该方法将语音转化为语谱图后输入到PCNN,得到输出图像的神经元点火序列及其熵序列作为语音情感的特征,利用其特征实现语音情感识别。实验结果表明,该方法可以有效地识别“高兴”与“平常”这两种不同的情感。该方法将PCNN引入到语音情感识别的应用研究中,开拓了语音和图像信号结合处理的新领域,同时对于PCNN的理论研究和实际应用具有重要的现实意义。     

Reconstruction of measurements in state estimation strategy against deception attacks for cyber physical systems

Without the known state equation, a new state estimation strategy is designed to be against malicious attacks for cyber physical systems. Inspired by the idea of data reconstruction, the compressive sensing (CS) is applied to reconstruction of residual measurements after the detection and identification scheme based on the Markov graph of the system state, which increases the resilience of state estimation strategy against deception attacks. First, the observability analysis is introduced to decide the triggering time of the measurement reconstruction and the damage level from attacks. In particular, the dictionary learning is proposed to form the over completed dictionary by K singular value decomposition (K SVD), which is produced adaptively according to the characteristics of the measurement data. In addition, due to the irregularity of residual measurements, a sampling matrix is designed as the measurement matrix. Finally, the simulation experiments are performed on 6 bus power system. Results show that the reconstruction of measurements is completed well by the proposed reconstruction method, and the corresponding effects are better than reconstruction scheme based on the joint dictionary and the traditional Gauss or Bernoulli random matrix respectively. Especially, when only 29% available clean measurements are left, performance of the proposed strategy is still extraordinary, which reflects generality for five kinds of recovery algorithms.