单次快前沿电脉冲信号的远距离低抖动传输

本文介绍了一种低时间间隔抖动的单次快前沿脉冲序列信号的远距传输技术.该技术采用远距离传输高重频信号来产生单次触发信号,利用该技术在距信号源端100 m处获得了时间间隔抖动峰峰值小于100 ps的单次脉冲信号.该技术对我国新一代高功率固体激光驱动器以及其它需要高精度同步的仪器或者设备的设计具有较高的参考价值.     

基于外差检测原理的绝对测距性能理论研究

基于双光学频率梳外差原理测距将长模糊距离、高精度和高更新率3个关键测距特性完美结合,使测量性能能够满足航空航天、科学研究和工业生产等众多领域的需求。然而所使用的双光学频率梳的脉冲时域宽度、重复频率及相对差值、脉冲的固有时间抖动等特性都将会影响测距的性能。对基于双光学频率梳外差原理测距进行了全面的理论分析,并数值模拟了数据脉冲宽度、双光学频率梳重复频率差、啁啾参量、定时噪声、脉冲类型等各因素对测距性能的影响。模拟结果在数值上验证了奈奎斯特采样定律对测距精度的显著影响,表明实验中数据脉冲宽度和重频差的选择应严格满足奈奎斯特采样定律;当飞秒脉冲序列存在一定的时间抖动时,重频差越小,测距性能越差;而脉冲的啁啾特性可转化为脉冲宽度的影响,随着啁啾的增大脉冲宽度被压窄,奈奎斯特采样频率对应的重频差临界值也会变小。通过上述数值分析,为研究人员在特定实验条件下优化测距性能提供了重要指导。     

基于时频分布的EEG中棘波的相关检测

本文提出了一种检测EEG中棘波的新方法。这种方法首先对仿真信号进行时频变换,得到模型棘波的时频特征。EEG信号经过时频变换后,计算EEG信号与模型棘波的时频相关系数,利用相关系数和时频分布中高频部分的能量,给出了一个确定EEG信号中是否含有棘波的指标,并定义这个指标为棘波概率。检测过程中,以棘波概率的大小检测棘波。实际应用表明,这种方法能够准确地检测EEG信号中的癫痫样瞬态特征     

A compact, low jitter, nanosecond rise time, high voltage pulse generator with variable amplitude

In this paper, a compact, low jitter, nanosecond rise time, command triggered, high peak power, gas-switch pulse generator system is developed for high energy physics experiment. The main components of the system are a high voltage capacitor, the spark gap switch and R = 50 Ω load resistance built into a structure to obtain a fast high power pulse. The pulse drive unit, comprised of a vacuum planar triode and a stack of avalanche transistors, is command triggered by a single or multiple TTL (transistor-transistor logic) level pulses generated by a trigger pulse control unit implemented using the 555 timer circuit. The control unit also accepts user input TTL trigger signal. The vacuum planar triode in the pulse driving unit that close the first stage switches is applied to drive the spark gap reducing jitter. By adjusting the charge voltage of a high voltage capacitor charging power supply, the pulse amplitude varies from 5 kV to 10 kV, with a rise time of <3 ns and the maximum peak current up to 200 A (into 50 Ω). The jitter of the pulse generator system is less than 1 ns. The maximum pulse repetition rate is set at 10 Hz that limited only by the gas-switch and available capacitor recovery time.     

光电式脉搏传感器及由其组成的血压仪的研制

人体脉搏和血压信号中包含着丰富的生理信息,是临床诊断的重要判据。本文介绍了光电式脉搏传感器的检测原理及其组成脉搏、血压检测仪的设计方案。采用集成式光敏元件和放大器芯片替代传统光敏器件进而实现对脉搏测量。而血压的测量采取较为普遍的KorotKoff原理测量法,利用压力传感器检测人体血压信号,并经过差分放大后,送至TC14433构成的数字血压表显示输出。该设计是光、机、电、计算机一体化测控技术的集中体现,是机电一体化产品改善人们生活和健康水平的代表。它的无创伤检测技术也是未来生物医学工程的重要发展方向。     

基于强磁体磁敏元件的微功耗脉冲传感器

介绍基于强磁体磁敏元件的微功耗脉冲传感器特点、工作原理及结构,并将其应用于电子流量计中。研究结果表明,该微功耗脉冲传感器应用于电子流量计中,具有很好的微功耗特性,很强的高、低频信号采集与输出性能,大幅提高了计量仪表的性能和计量精度。     

基于多尺度加权形态网络的燃气流量计健康状态评估

燃气流量计是天然气贸易计量的重要仪器,而其健康状态的改变会造成计量偏差。为了减少燃气企业的经济损失,本文提出了一种基于多模态数据扩充、形态学特征学习和多尺度自适应加权形态学网络的燃气流量计健康状态评估方法。首先,采用基于Wasserstein距离和谱归一化的ACGAN算法进行数据扩充。其次,针对燃气流量计振动信号数据的复杂性和噪声影响,提出了一种基于平均帽变换的形态学方法提取信号的正负脉冲信息。最后,针对非平稳、变工况的工业条件,引入多尺度自适应加权形态学网络,采用具有不同结构元素尺度的多个分量来分别提取脉冲信息,并利用自适应加权融合来增强提供强脉冲分量的尺度。通过实验结果表明,所提出的方法对燃气流量计健康状态评估的准确度超过94%。该方法对实际燃气贸易计量有重要的应用价值。     

电涡流传感器的脉冲激励与双参数检测

采用矩形脉冲作为激励信号,对电涡流传感器在位移检测过程中谐振频率及谐振阻尼的变化情况进行了研究分析.建立了以现场可编程门阵列(FPGA)为核心芯片的检测系统,用于产生所需要的矩形脉冲激励信号以及对传感器响应信号的欠采样.利用8 mm直径的电涡流线圈,对0～10 mm范围内碳钢目标靶的位移响应特性进行了测量,借助短时傅里叶变换分析了响应信号中频率成分的分布情况,同时获得了谐振频率及谐振阻尼的测量值.验证了通过脉冲激励同时获取电涡流传感器双参数检测的可行性.为研制基于电涡流效应的位移传感器及无损探伤传感器提供了一种新思路.     

A combined pulse modulation-processing method for ADCP applications

Acoustic Doppler Current Profiler (ADCP) based on the Doppler principle is the sonar for velocity measurements, which is mainly applied in the large-scale measurements of the oceanic current velocity. In order to satisfy the increasing requirement of high measurement resolution and accuracy compared with the traditional ADCP, this paper investigates the ambiguous functions of different signals and indicates that the pulse combined by several sinusoidal signals will improve the time resolution when keeping good frequency resolution. Then the present research proposes the modulation of a combined pulse as the ADCP׳s emitted signal, as well as the corresponding signal processing method. Two examples are demonstrated to show the effectiveness of the combined pulse modulation-processing method, and it is seen that: 1. the combined pulse has the same spatial resolution as one subpulse, while achieves better frequency resolution and better signal–noise ratio than the latter; 2. although the combined pulse results in a little worse signal–noise ratio than the long sinusoidal signal, the former has much higher spatial resolution; 3. the measurement accuracy of the combined pulse is better than the broadband coded-pulse when they have the same pulse width.     

67 GHz宽带谐波相位参考及其定标技术

作为非线性矢量网络分析仪的重要参考测量通道,谐波相位参考能够提供多频点、多波量以及复频率下的绝对相位测量能力。设计了基于共面波导非线性传输线方案的原型谐波相位参考样机,并提出了基于EOS光电采样系统的完整谐波相位参考定标技术,主要包括时基失配、平均去噪、相位对准、连接器失配与示波器复频率响应修正等流程。定标实验结果表明,原型样机能够在1 GHz功率27 d Bm信号激励下输出半峰值脉宽为22 ps的周期脉冲序列,其频带覆盖范围超过67 GHz,并在超高次谐波频点上拥有小于±10°的相位精度与小于±5°的相位可重复性。最后将原型样机装配到非线性矢网中,通过测量2 GHz信号激励下超窄时域脉冲发生器的输出时域信号,并将之与采样示波器测量结果进行比对,结果证实了谐波相位参考设计与定标技术的有效性与正确性。     

轴承异常声检测的特征量选择及分析

采用数字仿真和数字检测技术，对轴承异常声检测特征量的选择进行了分析讨论。结果表明，现行异常声检测用特征量平均幅值、有效值、峰值、波峰因数、峭度系数、超门槛脉冲数、超门槛脉冲有效值中，波峰因数和超门槛脉冲数两个特征量相结合，能够对轴承异常声进行最为可靠和有效的检测。     

Optical disc jitter generator and its calibration system

Jitter is one of the most important parameters for optical disc evaluation. This paper presents a design of a simulated optical disc jitter generator based on a sinusoidal frequency-modulated (FM) signal. An innovative method is proposed to calibrate the jitter generator based on the Bessel-zero method. Finally, measurement uncertainty of the calibration system is described. The results of theoretical analysis and experiments indicate that the expanded uncertainty of measurement is 0.13% in CD mode, and 0.18% in DVD mode, k = 2.     

基于STM32F4的ABS传感器输出正弦信号测量装置设计

汽车轮速传感器是防抱死制动系统（ABS）的关键部件之一,其性能的好坏直接决定了ABS性能的高低。磁电式ABS转速传感器的输出近似为正弦信号,通过对正弦信号幅值、频率、有效值的测定,可以分析获得传感器性能。本文以STM32F407为主控制板,以快速傅里叶变换为主要工具,设计了一款数字控制正弦信号测量装置进行各参数测量。经过实验验证,本装置可在5%的误差内精确测量输入信号的频率、有效值、峰值、失真度并还原信号波形。此外,为了便于观测,本设计借助蓝牙通信模块将测量数据同步上传到手机端。     

Note: Optical trigger device with sub-picosecond timing jitter and stability

We are presenting the design, construction, and overall performance of the optical trigger device. This device generates an electrical signal synchronously to the detected ultra-short optical pulse. The device was designed for application in satellite laser ranging and laser time transfer experiments, time correlated photon counting and similar experiments, where picosecond timing resolution and detection delay stability are required. It consists of the ultrafast optical detector, signal discriminator, output pulse forming circuit, and output driver circuits. It was constructed as a single compact device to optimize their matching and maintain stability. The detector consists of an avalanche photodiode--both silicon and germanium types may be used to cover the wavelength range of 350-1550 nm. The analogue signal of this photodiode is sensed by the ultrafast comparator with 8 GHz bandwidth. The ps clock distribution circuit is used to generate the fast rise/fall time output pulses of pre-set length. The trigger device timing performance is excellent: the random component of the timing jitter is typically 880 fs, the temperature dependence of the detection delay was measured to be 370 fs/K. The systematic error contribution depends on the laser used and its stability. The sub-ps values have been obtained for various laser sources.     

基于相位重合的全同步测频方法研究

文章对基于相位重合的全同步测频方法进行了研究。相位重合理论是目前比较流行的用于频率测量的理论,在检测被测信号与标频信号的相位重合脉冲后触发闸门,使计数闸门、被测信号和标频信号三者达到全同步,彻底消除了±1个字误差。相位重合检测电路、闸门、计数器等模块均在可编程逻辑器件FPGA中完成,使用方便,易于修改,经仿真达到了预期效果。     

基于CPLD的编码器信号处理电路设计

基于CPLD芯片,对增量式编码器输出信号进行处理,实现了编码器信号的整形滤波、倍频和鉴相。为了提高编码器的测量精度,设计了一种4倍频脉冲输出电路,提高了编码器的分辨率,并设计了鉴相电路,实现正反向的角度或速度测量。文中给出了Quartus原理图输入电路、时序仿真结果,以及试验测试结果。文中的研究在角度位移等测量领域有着广泛应用价值。     

正弦信号发生器波形抖动的一种精确测量方法

介绍了一种用三参数正弦波拟合算法实现的、绝对收敛的四参数最小二乘正弦波拟合算法 ,给出了收敛区间、绝对收敛判据以及实现过程。在此基础上讨论实现了正弦信号发生器波形抖动的评价问题。使用一个周期的正弦波曲线模型的滑动拟合法 ,评价了幅度、频率、直流偏移的抖动 ,以及相位与理论值之偏差的抖动情况。在幅度、频率、相位和直流偏移分别存在固定抖动的情况下 ,仿真评价了四个正弦参数各自的抖动情况 ,同时 ,在一个实测正弦波形曲线上进行的抖动分析 ,获得了非常明确的抖动测量结果。本方法评价正弦波信号抖动时 ,准确度高、分辨力好 ,且指标全面。     

A new method for wideband characterization of resonator-based sensing platforms

A new approach to the electronic instrumentation for extracting data from resonator-based sensing devices (e.g., microelectromechanical, piezoelectric, electrochemical, and acoustic) is suggested and demonstrated here. Traditionally, oscillator-based circuitry is employed to monitor shift in the resonance frequency of the resonator. These circuits give a single point measurement at the frequency where the oscillation criterion is met. However, the resonator response itself is broadband and contains much more information than a single point measurement. Here, we present a method for the broadband characterization of a resonator using white noise as an excitation signal. The resonator is used in a two-port filter configuration, and the resonator output is subjected to frequency spectrum analysis. The result is a wideband spectral map analogous to the magnitude of the S21 parameters of a conventional filter. Compared to other sources for broadband excitation (e.g., frequency chirp, multisine, or narrow time domain pulse), the white noise source requires no design of the input signal and is readily available for very wide bandwidths (1 MHz-3 GHz). Moreover, it offers simplicity in circuit design as it does not require precise impedance matching; whereas such requirements are very strict for oscillator-based circuit systems, and can be difficult to fulfill. This results in a measurement system that does not require calibration, which is a significant advantage over oscillator circuits. Simulation results are first presented for verification of the proposed system, followed by measurement results with a prototype implementation. A 434 MHz surface acoustic wave (SAW) resonator and a 5 MHz quartz crystal microbalance (QCM) are measured using the proposed method, and the results are compared to measurements taken by a conventional bench-top network analyzer. Maximum relative differences in the measured resonance frequencies of the SAW and QCM resonators are 0.0004% and 0.002%, respectively. The ability to track a changing sensor response is demonstrated by inducing temperature variations and measuring resonance frequency simultaneously using the proposed technique in parallel with a network analyzer. The relative difference between the two measurements is about 5.53 ppm, highlighting the impressive accuracy of the proposed system. Using commercially available digital signal processors (DSPs), we believe that this technique can be implemented as a system-on-a-chip solution resulting in a very low cost, easy to use, portable, and customizable sensing system. In addition, given the simplicity of the signal and circuit design, and its immunity to other common interface concerns (injection locking, oscillator interference, and drift, etc.), this method is better suited to accommodating array-based systems.     

Application of Hilbert-Huang Decomposition to Reduce Noise and Characterize for NMR FID Signal of Proton Precession Magnetometer

The parameters in a nuclear magnetic resonance free induction decay (FID) signal contain information that is useful in magnetic field measurement, magnetic resonance sounding and other related applications. A real time sampled FID signal is well modeled as a finite mixture of exponential sequences plus noise. We propose to use the Hilbert-Huang transform (HHT) for noise reduction and characterization, where the generalized Hilbert-Huang represents a way to decompose a signal into so-called intrinsic mode function (IMF) along with a trend, and obtain instantaneous frequency data. First, acquiring the actual untuned FID signal by a developed prototype of proton magnetometer, and then the empirical mode decomposition is performed to decompose the noise and original FID. Finally, the HHT is applied to the obtained IMFs to extract the Hilbert energy spectrum of the signal on the frequency axis. By theory analysis and the testing of an actual FID signal, the results show that, compared with general noise reduction methods such as auto correlation and singular value decomposition, combined with the proposed method can further suppress the interfered signals effectively, and can obtain different components of FID signal, which can be used to identify the magnetic anomaly, the existence of groundwater etc. This is a very important property since it can be exploited to separate the FID signal from noise and to estimate exponential sequence parameters of FID signal.     

基于数字锁相环的FPGA多通道频率测量系统设计

针对传统频率测量电路复杂、采集速度较慢的问题,基于FPGA(现场可编程逻辑门阵列),采用全数字锁相环对待测量信号进行倍频,辅以自适应时钟模块、计数模块和串口接收发送模块,设计了多通道频率测量系统,从而达到精简电路并实现对多路待测信号的快速精准测量。实验结果表明,对于100 Hz~10 MHz频率的稳定信号,测量时间仅为100 ms,与标准频率计相比,相对误差<0.5 ppm(1 ppm=10-6)。可用于多路频率信号的实时采集测量。