A Study on the EURAMET Comparison of Time Interval Measurement

At April 2003 there were 25 National Metrology Institutes in 25 countries that are members in the European Association of National Metrology Institutes (EURAMETs) agreed to participate in an inter-laboratory comparison for time interval measurement (TIM). The main target of this comparison, as mentioned by EURAMET, was to support the current calibration measurement capabilities for TI and to gain better understanding of the TIM. Cable delay measurement was taken as an example. The time delay of three different length coaxial cables (short, medium, and long) was measured. The majority of the laboratories used the Counter Method. There was a large span between the measurements for all cables (about 1 ns). Consequently, the measurement results that had been published at 2007 were not satisfied for the participant laboratories. In this article, we study the probable reasons for this considerable span between the different measurements for the same artifact.     

基于CPLD的时间间隔测量仪

介绍了一种根据量化时延原理 ,基于CPLD器件 ,测量分辨力达到 4 3ns的高精度时间间隔测量仪 ,此测量仪巳应用在GPS锁定的高稳晶振中。同时探讨了利用双量化时延法实现更高测量精度的可行性 ,给出了设计框图。     

脑电图机电压测量、时间间隔测量值的不确定度评定

本文依据JJG1043-2008《脑电图机检定规程》,对脑电图机电压测量、时间间隔测量值的不确定度评定进行分析。     

A Delay Generation Technique for Narrow Time Interval Measurement

A new architecture for the on-chip measurement of short-time intervals is proposed in this paper. The measurement method is similar to a typical low-voltage measurement setup where the input signals are first amplified and then measured to relax the dynamic range of the succeeding analog-to-digital converter. In the proposed method, narrow time intervals are first amplified by a time amplifier (TAMP) and then measured by a time-to-digital converter. A delay-locked-loop (DLL) circuit is utilized to design a feedback time amplifier in which the gain is readily programmed by input data to any integer value within a range specified by the number of delay cells in the DLL. The TAMP's gain remains rather unchanged under process and temperature variations due to the inherent negative feedback of the DLL system. The circuit is implemented using complementary metal--oxide semiconductor (CMOS) 0.18- $muhbox{m}$ technology occupying less than 0.63 $hbox{mm}^{2}$ of the silicon area. The simulation results show that the proposed scheme can successfully be employed to measure time intervals in the range of a few tens of picoseconds with acceptable accuracy.      

高精度高分辨力时间间隔测量的技术实现

介绍1 ns分辨力时间间隔测量的技术实现和总体方案设计,并对高分辨力频率测量所采用的模拟内插技术和实现的技术途径进行了简要分析.研究证明采用模拟内差计数方法能够满足高精度、高分辨力的时差测量,提高实现1 ns的时间间隔测量能力.     

Random Errors in Time Interval Measurement Based on SAW Filter Excitation

This paper deals with the time interval measurement method that makes use of a surface acoustic wave (SAW) filter as a time interpolator. The method is based on the fact that a transversal SAW filter excited by a short pulse can generate a finite signal with highly suppressed spectra outside a narrow frequency band. If the responses to two excitations are sampled at clock ticks, they can be precisely reconstructed from a finite number of samples and then compared to determine the time interval between the two excitations. We have analyzed noise contributions to the overall uncertainty of the interval measurement. The following four noise sources have been considered: (1) noise of excitation; (2) noise of amplifier; (3) quantization noise of the analog-to-digital converter; and (4) clock and sampling jitter. The main goal of the analysis was to determine the uncertainty of the measurement in dependence on the variances of contributing noises, and the magnitude of the frequency response of the filter. First, each uncertainty component has been analyzed under general assumptions. Second, a general narrow-band filter has been investigated. Finally, we have found the solution for an ideal narrow-band filter where we have obtained simple illustrative results. The results have been compared to Monte-Carlo simulations. Good agreement between theory and simulation has been demonstrated except for the outliers due to the false ambiguity solution that occurs with large measurement errors and small relative filter bandwidth.     

基于TDC-GP1的时间间隔测量系统设计

本文针对时间测量技术的现状及应用需求,介绍了高精度时间-数字转换器TDC-GP1的技术特性,提出了一种高精度时间间隔测量的实现途径,设计了高精度时间间隔测量系统,并通过实验验证了该系统的可行性。     

基于时空关系的超高分辨率时间间隔测量方法

在量化时延原理的基础上,提出了一种基于时空关系的超高分辨率时间间隔测量方法.利用时频信号在特定媒质中传播的时延稳定性这一自然现象,将被测时间间隔量化,结合相位重合检测技术,使对时间量的测量转化为对空间长度量的测量,大大提高了测量的分辨率和测量系统的稳定性.实验结果表明被测时间间隔的测量分辨率取决于作为两路延时单元的长度差,当两路延时单元的长度差设置在毫米级或亚毫米级时,可达到10 ps级至ps级的超高测量分辨率.     

基于FPGA的重力仪干涉条纹和时间间隔计数

介绍了用现场可编程门阵列在绝对重力仪中实现落体下落距离和相对应的时间间隔测量的原理及方法.阐述了基于Altera公司DE2开发板和Nios II处理器为核心而构建的可编程片上系统以及"数字移相法"的应用.最后分析了该测量系统在时间间隔测量运用的不确定度估算.     

改进的零差时间间隔法振动幅相特性校准技术

详细描述了一种改进的基于虚拟仪器技术的时间间隔法。按照该方法建立的振动幅相特性校准系统,使用普通迈克耳孙激光干涉仪和双通道同步数据采集卡,能够在800Hz频率范围内实现加速度传感器复灵敏度的精确校准,满足相关国际标准的不确定度指标要求,幅值不确定度0．5％,相移不确定度1^o（k=2）。利用加速度仿真试验和振动标准套组比对试验,验证了该改进方法的正确性,并对其相关特性进行了较深入的分析。改进的时间间隔法具有软件算法简单高效、硬件平台通用经济的优势,尤其适于在发展中国家的计量院和国内的激光绝对法振动校准实验室推广应用。     

微光成象系统中实时降噪的优化设计

微光电视工作于极低照度或恶劣环境下，输出信噪比明显降低，目标完全淹没在背景噪声中，使探测率大大下降。提出了用帧间处理技术消除加性噪声。论述了字长和滤波系数的选择原则。研究了实时去噪的几项关键技术，算法和符号位的设计，各部分工作时间分配以及大背景噪声下时种同步方法。     

Algorithms for the Optimum Estimation of the Parameters of a Radio Signal in a Measurement Time of Less Than a Period and a Nonmultiple of a Period in Which the Result Is Tied to the Beginning of the Measurement Interval

Optimum estimates of the parameters of a noisy (white noise) sinusoidal radio signal of known frequency are considered, based on an investigation of the likelihood function, when the measurement time is less than a period and a nonmultiple of a period. Estimates are presented for the phase shift and the amplitude in the presence (absence) of a constant component and nonlinear distortions when the result is tied to the beginning of the measurement interval.     

Extended Time Sampling for Accurate Optical Pulse Reflection Measurement in Level Control

Pulse reflection methods play an important role in the diversified fields of industrial measurement. The paper reports on an optical short-range radar with superior resolution using a modified sampling procedure. The developed system has been tested successfully for level control applications, such as for measuring the meniscus of the molten steel in the mold of a continuous casting installation.     

用Poiseuille理论确定网印中的最佳网距

从丝网印刷过程中网版的受力分析出发,运用Poiseuille理论建立了满足最优丝网印刷条件的网版速度和受力模型.求解模型将网距限定在了一个范围内,在此基础上进一步分析了影响网距的因素.     

高准确度脉冲时间间隔的产生

本文介绍一种数字式高准确度脉冲时间间隔的产生原理和技术特征 ,延迟时间范围 0～ 1s,1s以内时延的不确定度小于1ns。     

Measurement of Perceptual Motor Load Using the Interval Production Task

This study investigates the use of the interval production task as a secondary task for the quantification of perceptual motor load. In this case, the variability in foot tapping is used as the index of performance in the secondary task. Experiments investigating the effect of tasks of varying motor and perceptual loads on tapping are reported. The study concludes that although the interval production task can be used to differentiate between motor loads, its utility as an index of perceptual load is questionable.     

Algorithm for the Confidence Interval of a Combined Measurement Error

An algorithm is proposed for calculating the confidence interval of a measurement error in terms of its partial components and a method is given for implementing it in the form of a programmed calculator.     

用小角度测量仪校准合象水平仪的不确定度问题探讨

介绍了微分筒式小角度测量仪的构造及测量原理 ,对使用该小角度测量仪校准合象水平仪时的测量不确定度进行了分析计算 ,指出使用微分筒法校准合象水平仪准确度高且操作方便。     

Pre-Calibration of the Phase Interpolator of a Precision Time Interval Meter

Measurement Techniques - The issues of precision determinations of time intervals for which results are essential, such as to estimate the metrological characteristics of structural systems of...     

基于IMEOWA的区间型绩效信息测评方法

在对区间数运算规则、比较与排序方法的讨论的基础上,将MEOWA( Maximum Entropy Ordered Weighted Averaging)方法扩展到区间数的评价中,提出了基于IMEOWA(Interval MEOWA)的绩效测评方法.以最大熵修正权重向量,以可能度矩阵的排序向量进行区间数排序,再利用OWA...