双时间法在脉冲型流量传感器检定中的应用

设计了一种新型的双时间法计数器 ,并成功地应用于检定脉冲型流量传感器 .试验表明 :该计数器性价比高 ,使用方便 ,工作可靠 ,可以缩短检定时间 ,在一定条件下 ,可用较小的标准容器检定较大口径的流量传感器 ,并且比常规检定方法具有更高的计数精度     

双计时在检定流量变送器中的应用

双计时在检定流量变送器中的应用叶吉生（甘肃计量检定所，７３００７０）一、概述目前在流量标准装置上检定流量变送器时，多采用一台计时器。由换向器的切换控制，同步驱动流量脉冲的计数和测量时间的计时。由于换向的随机性而引入了流量脉冲的计数误差。该误差通常≤１...     

液体流量标准装置脉冲采样误差分析

正流量计检定(或校准)时,脉冲采样误差的大小直接影响流量计的准确度等级。根据装置脉冲采样的原理,可以发现脉冲采样误差主要来自于换向器的换向时间误差和计数器的计数误差。1.换向器换向时间误差分析换向器利用机械部件改变介质流动方向,同时提供反馈信号,让采集系统对流量计检定准确计时。该装置采用开式换向器,通过行程差法检定,其A类标准不确定度:0.0069%、0.0023%,B类标准不确定度0.0036%,其合成标准不确定度为0.0081%,可见换向     

数字式电秒表测量误差的检定

<正>数字式电秒表的检定可以按照JJG237-2010《秒表检定规程》进行。按照规程用于检定数字式电秒表的标准器:标准时间间隔发生器,输出信号类型:单路输出(正、负脉冲宽度)、双路输出(两个正脉冲的时间间隔、两个负脉冲的时间间隔)。测量误差的检定:(1)一对空接点的闭合持续期的测量——时间间隔发生器单路输出一个负脉冲,脉冲宽度等于受检点,输出信号接在被检电秒表的Ⅰ、Ⅱ端或Ⅰ、Ⅲ端;(2)一对空接点断开持续期的测量——时间间隔发生器单路输出一个正脉冲,脉冲宽度等于受检点,输出信号接在被检电秒表的Ⅰ、Ⅱ端     

一种基于高频脉冲插值的角加速度测量系统

设计了一种角加速度测量系统.测量方法是通过高精度光栅和红外光电管获取转速信号,再对转速信号进行高频脉冲插值,从而把转速信号转化为高频脉冲数,对高频脉冲数处理后得到转轴的角加速度.测量系统采用FPGA与单片机相结合的模式,FPGA用于产生高频脉冲、对转速信号插值,并对插值后的信号进行计数,单片机读取计数结果并进行处理.实验验证表明,该角加速度测量系统有较高的测量精度.并通过理论分析找到了影响系统测量精度的原因.     

基于机器视觉的水表小流量检定方法研究

针对目前水表小流量检定时间长,人工读数不准确等原因,提出了一种基于机器视觉的水表小流量检定方法。通过工业相机以自适应的采样频率采集水表梅花转子图像,利用图像叠加原理,以检定开始时转子图像为背景,相机后续获取每一帧图像在此背景上作叠加处理。根据转子转动过程中图像叠加后的明暗占比大小的变化规律对其转动齿数进行计数,用双计时法通过脉冲当量得到水表指示体积。利用液体流量标准装置,对水表进行检定,采用静态质量法,通过称重箱获取标准体积,计算水表误差。根据实验结果,在小流量检定时,该方法在缩短检定时间、减少用水量后可得到与人工读数法一致的结果,可解决气泡带来的读数干扰,并能有效提高检定效率。     

提高工效的微机化压力检定系统

微机化压力检定系统的研制可实现压力仪表检定过程的全（半）自动操作,可自动采集数据,自动数据处理和误差判断,自动打印检定记录和检定证书.对标准器进行数值修正,可采用已有的标准设备,使研制成本大大降低;对检定记录可进行存储、查询和修改,实现检定过程无纸化.从而使检定工作人员从烦琐的手工劳动中解脱出来,大大提高了工作效率,规范了计量工作的科学化管理.     

基于双计时原理的水表和换向器检定方法研究

为提高水流量标准试验装置检测大口径机械式水表示值误差的检定精度,提出一种基于动态启停双计时原理的检定方法.依据两台计时器分别记录的被检水表通流时间和工作量器进水时间,可以方便地修正示值误差并对换向系统工作特性进行监测.研究结果证实,换向气动电磁阀不对称工作特性是换向系统不确定度的主要来源,双计时法能明显提高机械类流量仪表的示值误差检定不确定度.     

企业计量资料的建立与管理

正一、计量器具技术档案1.计量标准技术档案每建立一项计量标准,至少应包含以下内容:(1)计量标准合格证书;(2)检定系统框图;(3)建立计量标准技术报告;(4)计量标准稳定性考核记录;(5)计量标准测量重复性考核记录;(6)计量标准器及主要配套设备历年检定证书;(7)计量标准履历书;(8)计量标准操作程序;(9)被检计量器具计量检定规程(现行);(10)标准器及     

静电电荷衰减试验仪检定装置研究

为给电荷衰减时间测试仪器提供溯源,研制了一套电荷衰减试验仪检定装置.该装置主要由双指数形标准衰减电压源、标准脉冲分压器和计算机数据采集处理系统等三个重要部分组成,数据采集处理系统采用虚拟仪器软件Lab Windows/CVI编制,该装置的扩展不确定度为0.66%.     

High Speed Photon Number Resolving Detector with Titanium Transition Edge Sensor

We have developed new photon number resolving detectors with titanium transition edge sensors (Ti-TESs) for a high counting rate operation in quantum information. The titanium superconducting films were fabricated by ultra-high vacuum electron beam evaporation, and showed a sharp superconducting transition at 359 mK. The device was coupled to a single mode optical fiber, and cooled down to 100 mK. Some of optical responses of the devices were measured by illuminating heavily attenuated laser pulses at wavelengths of 405 and 1550 nm. As a result, the device showed a fast decay time constant of 300 ns, which enables the operation at the counting rate of 400 kcps. The energy resolution was 0.76 eV at 405 nm and 0.68 eV at 1.5 μm, that make it possible to clearly resolve the number of photons of incident laser pulses. These features of the high counting rate operation and the reasonable energy resolution are very promising for quantum information field.      

Scintillation in anodic Ta2O5 films

The scintillation of anodic tantalum oxide was investigated by counting the number of breakdown events during anodization at a constant current density. A theory is developed which qualitatively explains the variation in the number of breakdown pulses with time and voltage for different current densities and different electrolyte resistivities. The theory also allows definition of a limiting anodization voltage which increases with the logarithm of the current density. Several experiments are presented which are in agreement with the theory.     

Photon number resolving in geiger mode avalanche photodiode photon counters

Abstract

The paper reports on research and development in the field of avalanche photodiodes operated as photon counters in a Geiger mode. A technique has been developed and tested that permits estimation of the photon number involved in a detection process. It can be applied in a time correlated photon counting experiment simultaneously with original required time interval estimation. A time walk compensation circuit provides uniform electrical pulses, and the time interval between them is related to the number of photons detected. Employing a picosecond event timing device, the photon number can be estimated within the dynamic range 1–1000 photons with resolution better than a factor of three.     

A new method of absolute temperature measurements

Summary Preliminary experimental data shows the possibility of measuring temperature by the number of voltage noise pulses. In theory, this method provides absolute and comparative temperature measurements over a wide range: the upper limit being that at which the resistor is destroyed; the lower boundary, in theory, is limited by the superconductivity temperature of the resistor material. The sensitivity of the method rises with decreasing temperatures.There are reasons to believe that by counting pulses over a longer period of time with highly stable temperature fields and amplifier gain with an adjustable threshold of discrimination, it will be possible to raise the absolute accuracy of temperature measurements as compared with other existing methods.     

在线式光电自动计数方法及应用

利用激光器和光电管设计了激光光电传感器,当有工件通过时光被遮挡住,光电管输出一个脉冲,对此脉冲信号进行计数即为工件数。基于这种光电检测方法研制了一台在线式光电自动计数仪,并对激光光源进行缩束准直,解决了小工件计数的难点。实验表明,该仪器计数准确、检测速度快,实用性强。     

A Novel Method for Signal Energy Measurement

This paper presents a method to measure the energy in a signal without the use of an analog-to-digital converter. This is especially useful for inexpensive microprocessor-based systems where a large number of multiply operations proves too time consuming. The approach is based on counting the number of pulses from the output of a voltage controlled oscillator (VCO) whose control voltage is the square of the input signal. The validity of this approach has been demonstrated in the measurement of the energy in the acoustic envelope of isolated words spoken in French.     

Counting signals from radioactivity-measurement systems

The original time-interval distribution of Poisson events, as for instance those originating from the decay of a radioactive source, is modified by the finite width of the electrical pulses. For the simple case of assumed rectangular pulses it is found that the available counting signals can be subdivided into single pulses and pile-up pulses (of a given order). The probability for observing a counting signal of order i is derived in a simple way and expressions for mean width and count rate are given. Confirmation has been obtained both by simulation and by experiments with a random-pulse generator.     

Determination of the Time Dependence of Periodic Optical Signals by Correlation Spectroscopy

A method is described for determining the time dependence of a periodic optical signal by measuring the autocorrelation function and counting rate distribution of the anode pulses of a photomultiplier, which is used as a light detector. The effect of amplitude and frequency fluctuations is discussed. The method is applied to the determination of fast periodic concentration variations generated by the mixing process of three free jets, one CO₂ jet and two air jets. The Raman technique is used as a molecular number density probe.     

Direct measurement of photon number statistics at telecom wavelengths using a charge integration photon detector

In optical quantum information technology, a photon number resolving detector (PNRD) is the basic device for developing photonic quantum computers. The demands for the PNRD are high quantum efficiency and wide dynamic range. We have developed a charge integration photon detector (CIPD) with a quantum efficiency of 80% at telecom wavelengths. The repetition rate of the CIPD is as low as 40 Hz at present, but it can be applied for measurement of short pulses. We report the capability of the CIPD for multiphoton counting over 10 photons, its responsivity to the short pulses, and its high linearity using a binary intensity modulated short pulse (2 ns) train and simultaneous irradiation of two kinds of pulses.     

Side effects of the use of cylindrical grooves in planar intrinsic germanium detectors

One technique for producing planar intrinsic germanium detectors involves machining a deep groove in the detector crystal just inside the outer cylindrical surface and running from one plane face almost to the other. Weak collection fields near the base of the groove can then be expected to lead to the appearance of some output pulses having very long rise times. Two detectors of this type have been examined. It was found that at low counting rates and in the absence of pulse shape discrimination slowly rising pulses were processed as if they formed a continuum of low energy pulses extending into regions where with a mono-energetic gamma source pulses would not normally be present. At high counting rates the smallest slow pulses, which escape the attention of the pile-up detection circuits, were found to give rise to lines with high energy tails, and to excess rate dependent line broadening.