用调频正弦波形和示波器同步原理模拟纵波

基于示波器同步原理,用固定周期的调制电信号模拟机械简谐振动源,用调频波形模拟质点的稠密区和稀疏区,用不同步的左右移动波形模拟质点作简谐振动,实现了在示波器上模拟纵波.     

示波器实验的教学改革

示波器的原理和使用是大学物理实验教学的一个基础实验项目.传统的教学仅限于向学生介绍示波器显示波形的原理,测量信号电压、频率和周期等参数,以及采用利萨如图形测量待测信号频率等内容.随着科技的进步,传统的模拟示波器已经逐步被数字示波器所替代,一些高校实验项目也做了相应的调整.本课题探讨数字示波器的实验拓展,即结合压电传感器...     

学生示波器常见故障与维修

以实验室常用的Ｊ２４５９ 型学生示波器为例, 介绍常见的波形失真、扫描线偏移等故障的检修方法     

将普通示波器改为慢扫描二踪数字存贮示波器的附加装置

普通示波器在显示缓慢变化的信号时不能显示为一连续波形,用长余辉示波管显示缓变信号也不够理想,而一般商品化数字存贮示波器价格昂贵(5000元以上)。本文所介绍的这种装置,采用普遍使用的数字集成电路,其成本不超过100元,且不需对普通示波器作任何改动,就可实现对缓变信号的实时显示、冻结与存贮。由于具有双通道同时显示及滚动扫描的功能,这就使对波形的比较与观察变得非常清楚明了。用这种装置对普通示波器的更新改造简单易行,并且对普通示波器的单独使用无任何影响。     

传输线中脉冲信号反射波的测量和应用

将高频单脉冲信号输入同轴电缆，借助数字存储示波器记录输入、输出端的波形和相对延时，可以测量传输线的电缆长度和衰减系数，同时观察脉冲波形因色散引起的畸变．     

HP54505B数字示波器计算机实时控制与数据处理系统

利用IEEE-488多功能GP-IB接口卡使HP54505B数字示波器与PC486微机系统建立了通讯,在此基础上用QuickBASIC语言开发了一套计算机控制实时信号采集与数据处理软件,实现了示波器工作条件设置、数据采集、参数测量、波形再现、数学处理、格式转换、结果输出的自动化,适用于HP54500数字示波器系列,在我们实验室中得到了很好应用。     

基于PAC的测控系统设计与实现

为实现某化学分析测量仪器自动化测控需求,通过分析研究数字量与模拟量输入监测及温度、电磁阀等控制技术,设计组建了基于PAC的组件式测控系统,编制了基于模块化开发、工作流程的数据结构设计、多线程技术的测控软件,经过多次实验验证,测控系统稳定可靠,实现了无人值守长时间运行。     

F-H实验测量方案的改进

主流智能化F-H实验仪测量方案不合理,测得的物理图像容易失真.为了能在手动扫描时连续扫描出波形,设计了2种方案:采用数字存储示波器的X-Y扫描仪的工作方式,重复记录多条曲线并同时显示在屏上;利用USB-9219数据采集卡,4个同步测量通道电气隔离,避免共地.改进方案能在较短的时间内全面展现F-H管的工作特性.     

基于STM32的简易数字示波器设计

随着科学技术的发展,示波器已成为电路调试测试的必备仪器之一,其发展速度和应用远超其他测量仪器。本设计完成基于Cortex-M3内核单片机设计的数字示波器,硬件电路设计主要包含STM32F103RCT6单片机最小系统、信号调理电路、TFT液晶屏显示电路、按键电路,电源电路;软件设计主要包含模数转换处理编程、TFT液晶屏波形显示编程、按键功能控制编程和数据算法处理编程^[1]。系统信号调理电路将输入信号衰减、限幅、叠加,最后输入单片机自带的模数转器中,将模拟量转换为数字量,最后经过单片机转换处理,通过液晶屏将采集到的波形信号显示出来。系统设计具有功耗低、体积小、成本低等特点,具有一定的应用前景和研究价值。     

基于边界扫描的雷达嵌入式测试和诊断技术

为解决因雷达数字化、高速化发展引起的测试和诊断技术难题,提出了基于边界扫描的雷达嵌入式测试和诊断方案,介绍了系统的硬件架构和软件设计。该方法可以在雷达系统正常执行任务期间,实时检测数字集成电路的故障,并将故障定位到芯片引脚。对低速数字信号,可以采集完整的信号波形;对较高速度的数字信号,可以通过多次采集和统计分析的方法提取故障特征。该方法已通过试验验证。     

Fourier synthesis of 9.6-GHz optical-pulse trains by phase locking of three continuous-wave semiconductor lasers

Fourier synthesis of optical-pulse trains based on optical phase locking of three cw semiconductor lasers has been demonstrated by use of a semiconductor optical amplifier as a four-wave mixer. The temporal waveforms of the pulse trains were directly observed at a repetition rate of 9.6 GHz by a fast sampling oscilloscope. The FM sideband heterodyne technique was employed to realize a stable homodyne optical phase-locked loop.     

研制超宽带全光取样示波器设备

全光取样示波器是研究与开发超高速光通信系统和光子交换网络的关键性测试仪器设备. 本文简介了我们自行设计和研制出的超宽带全光取样示波器设备的实验样机系统, 并报道了我们已取得的初步实验结果. 采用自主研发的高稳定性被动锁模飞秒光纤激光器作为该光学示波器的光脉冲取样源, 我们通过利用高度非线性光纤中的四波混频效应, 成功地实现了对脉宽为1.8ps、重复频率分别为10GHz和40GHz的光脉冲信号的全光取样. 然后通过数字信号处理和计算机图形处理, 得到了再现后的超短光脉冲信号波形, 并测出了其脉冲宽度值为2.3ps. 借助于该光学取样示波器实验样机, 我们还成功地完成了对脉宽为1.8ps、经过伪随机数据序列调制后的10Gbit/s和40Gbit/s光数据信号眼图的精确测量. 这是我国首次报道有关超宽带全光取样示波器设备的实际研制工作及其相应的实验测试结果. 所得到的有关超短光脉冲信号波形的测试结果也与用70GHz宽带电子示波器和超快光电探测器组成的常规光电测量系统所获得的结果进行了比较, 清楚地表明了我们研制出的全光取样示波器实验样机比后者具有更高的时间分辨率和更大的测量带宽.     

Measurement of subpicosecond optical waveforms using a resonator-based phase modulator

We propose a method for the measurement of periodic optical waveforms based on the use of an electrooptic phase modulator placed in an optical Fabry-Perot or ring resonator. Significant broadening of the modulation spectrum extends the recently developed method of periodic modulation for pulse characterization into femtosecond scales. We numerically demonstrate the characterization of a 300-fs optical pulse. We also present a technique based on the temporal fractional Talbot effect for restoration of the pulse phase profile. After fast linear processing, subpicosecond pulses will be observed on the screen of a real-time oscilloscope. This complete characterization of optical pulses is entirely linear and therefore highly sensitive and simple in implementation.     

Integrated optical temporal Fourier transformer based on a chirped Bragg grating waveguide

We experimentally demonstrate the first integrated temporal Fourier transformer based on a linearly chirped Bragg grating waveguide written in silica glass with a femtosecond laser. The operation is based on mapping the energy spectrum of the input optical signal to the output temporal waveform by making use of first-order chromatic dispersion. The device operates in reflection, has a bandwidth of 10 nm, and can be used for incident temporal waveforms as long as 20 ps. Experimental results, obtained through both temporal oscilloscope traces and Fourier transform spectral interferometry, display a successful Fourier transformation of in-phase and out-of-phase pairs of input optical pulses, and demonstrate the correct functionality of the device for both amplitude and phase of the temporal output.     

基于光反馈自混合干涉效应波形转折点的智能识别

对光反馈自混合干涉信号波形转折点的智能识别进行了理论分析和实验研究。首先经对光反馈自混合干涉信号特点的分析，发现其波形转折点可以作为外部物体运动位移实时测量的依据。通过对信号波形的逐步处理可以获得波形转折点的位置，以此为基准点可以实现位移的精测。实验测试结果同理论分析吻合较好。若系统进入较复杂状态，识别出的位置与其实际位置出现偏差，不再是单一值，可以对转折点位置的所有值取平均，从而得到其对应的精确位置。     

动态杨氏模量实验的降噪优化设计

对杨氏弹性模量测量仪的关键性组件——杨氏弹性模量测量仪及示波器进行有效改进,从而彻底消除了共振声音相互干扰的问题,并使示波器的使用更方便,易于调节出信号,实验效果非常明显。     

Unified approach to short optical pulse recording and spatial imaging with subwavelength resolution

We propose and numerically demonstrate a simple method for measuring waveforms of optical pulses that have spectral bandwidths much larger than the passband of the measuring system, thus enabling a kind of temporal superresolution. The technique is based on pulse intensity modulation that contains high-order harmonics. Parts of the pulse intensity spectrum that are shifted as a result of the modulation, are moved over (“umklapped”) to the center of the passband, transmitted and then recorded by an oscilloscope. The pulse intensity spectrum is restored by parts from the Fourier transform of a few oscillograms, measured after performing the temporal shifts between the pulse train and the modulation. A similar approach is applied for achieving subwavelength spatial resolution in far -field microscopy. The spatial modulation is performed by a diffraction grating. The method allows one to restore a subwavelength object in a single measurement.     

Clutter interference and the integration time of echoes in the echolocating bat, Eptesicus fuscus

The ability of the echolocating bat, Eptesicus fuscus, to detect a sonar target is affected by the presence of other targets along the same axis at slightly different ranges. If echoes from one target arrive at about the same delay as echoes from another target, clutter interference occurs and one set of echoes masks the other. Although the bat's sonar emissions and the echoes themselves are 2 to 5 ms long, echoes (of approximately equal sensation levels--around 15 dB SL) only interfere with each other if they arrive within 200 to 400 microseconds of the same arrival time. This figure is an estimate of the integration time of the bat's sonar receiver for echoes. The fine structure of the clutter-interference data reflects the reinforcement and cancellation of echoes according to their time separation. When clutter interference first occurs, the waveforms of test and cluttering echoes already overlap for much of their duration. The masking effect underlying clutter interference appears specifically due to overlap, not between raw echo waveforms, but between the patterns of mechanical excitation created when echoes pass through bandpass filters equivalent to auditory-nerve tuning curves. While the time scale of clutter interference is substantially shorter than the duration of echo waveforms, it still is much longer than the eventual width of a target's range-axis image expressed in terms of echo delay.     

激光诱导AZ31B镁合金薄板动态响应实验研究

为分析在激光冲击波作用下AZ31B镁合金薄板背面的动态响应,采用聚偏氟乙烯贴片传感器与数字示波器对强激光诱导的冲击波进行测量,得到压电波形,结合冲击波的传播特性,对弹塑性双波的传播规律进行了研究。结果表明:激光诱导的材料动态响应是快速的;压电波形图反映出的弹性前驱波与塑性加载波传播到靶材背面的时间与理论时间相符;弹性前驱波能量小引发的波形振幅较小,紧随着的塑性加载波能量大并引起较大振幅波动,弹塑性双波卸载过程与紧接着的加载过程导致了压电信号的波动振幅提高。     

基于对称3×3耦合器的光纤干涉信号的软件解调技术

从基于对称3×3耦合器的光纤干涉信号中解调出被测物理量,需要经复杂的运算.本文提出用软件来模拟实现了信号的解调,省去了繁杂的模拟运算电路,并且通过软件解调运算,可得到运算中间各过程的波形图,也可以分析出各种误差和产生误差的原因,对硬件解调电路的设计有指导性意义.