立体声声像与李沙育图监测

从声像概念出发，由实验监测技术阐述了立体声声像与李沙育图图形的关系，对立体声系统的声像测试有实用的意义。     

编程软件MATLAB在大学物理实验教学中的应用探讨

运用编程软件MATLAB对两个物理实验进行了仿真，其结果有助于学生加深对实验的理解，提高物理实验的教学效果。     

基于李萨如图的光纤分布式传感系统定位方法

提出了一种基于传感信号李萨如图的定位方法,对扰动进行定位。根据李萨如图的拟合椭圆,研究了拟合椭圆参数和时延之间的线性关系。利用实验室建立的2km的Mach-Zehnder(MZ)干涉仪型光纤分布式扰动传感系统,在2 Mb/s的采样速率下,应用李萨如图定位方法实现了100m的定位精度,多次测量的平均定位误差为50m,小于互相关法的定位误差。该方法简单,无需信号的先验知识,具有更好的稳定性。     

Phase Maps Retrieval from Sequences of Phase Shifted Images with Unknown Phase Steps Using Generalized N-Dimensional Lissajous Figures—Principles and Applications

This article presents an alternative approach for retrieving phase information from a sequence of images with unknown phase shifts. A sequence of five or more discrete interferograms with unknown and different phase shifts are used to determine the parameters of N-dimensional Lissajous figures. A set of N-dimensional discrete points are used to calculate the relative phase shifts. Once zthe phase shifts are determined, the phase values for each image pixel are determined from a generalized phase calculation equation for irregular phase shifts. The article presents the physical and mathematical basis of the developed approach and discusses some results obtained from simulated data and real data from controlled experiments.     

双振镜点扫描三维形貌测量系统

针对远距离大尺寸物体三维形貌测量的要求,设计并实现了基于激光三角法原理的双振镜点扫描三维形貌测量系统。介绍了系统的结构和测量原理,并对系统进行建模,推导了被测物体表面测量点的三维坐标计算公式。构建了原型系统,利用专用的二维平面靶标在测量空间内自由摆放数次,根据靶标上特征点及其像点间的位置关系,以坐标系转换为基础实现了测量系统结构参数的现场标定。利用李萨如图扫描模式分别对靶标平面、已知直径的球面及石膏像自由曲面进行了测量实验。结果表明,测量距离1m处,测量点到拟合平面的距离误差均值为0.70mm,球面直径测量误差均值为0.51mm;测量距离10m处,测量点到拟合平面的距离误差均值为17.85mm。该系统可用于远距离大尺寸物体表面的三维形貌测量。     

大气压介质阻挡高频放电三种模式的Lissajous图形

大气压介质阻挡放电存在多种放电模式。本文利用高频高压电源,分别进行了大气压氦气均匀的介质阻挡放电和大气压空气丝状介质阻挡放电的试验,通过测量外施电压、回路电流和拍摄ICCD短时曝光的放电图像,研究了氦气单脉冲辉光放电、多脉冲辉光放电和空气丝状放电的Lissajous图形特征。结果表明:两种辉光放电均起始于汤森放电,放电电流最大时为辉光放电;而丝状放电为流注放电。高频下辉光放电的Lissajous图形不同于工频的两条平行线,而是左右两边有一次曲线性阶跃的平行四边形;伪辉光放电的电流波形每半个周期内有几个电流脉冲,Lissajous图形中放电阶段对应的两条边就有几次曲线性阶跃;丝状放电的Lissajous图形近似为平行四边形。     

Testing Biquad Filters under Parametric Shifts Using X-Y Zoning

Testing mixed-signal circuits is a difficult task due to defect modeling challenges, observability and controllability restrictions and ATE bandwidth limitations. In this paper, the X-Y Zoning test of a Biquad filter is addressed to select the optimal excitation frequency and the best partition of the X-Y plane. Thus we obtain the best sensitivity of the BIST scheme to parametric shifts of the parameters defining the filter. The study has been particularized to shifts in the natural frequency f₀ of the Biquad filter. Analytical results on the best input as well as the best partition of the observed X-Y Lissajous plots are obtained. Extensive MATLAB simulations validate the proposal, which has also been validated experimentally. For these experiments, multiple implementations of the Biquad with nominal and shifted parameters have been performed using a commercial Field Programmable Analog Array (FPAA). The experimental measures show good correlation with the analytical expressions and the simulations performed, and validate the proposed testing methodology.Ricard Sanahuja is Associate Professor in the Electronic Engineering Department of the Universitat Politècnica de Catalunya in Manresa (Barcelona), with teaching responsibilities in microelectronics. His current research interest is centred in Mixed-Signal Testing which offers the bases of his Ph.D. Sanahuja received his Electronic Engineering degree in 1997 from the Universitat Autònoma de Barcelona and Universitat Politècnica de Catalunya.Victor Barcons is Associate Professor in the Electronic Engineering Department of the Universitat Politècnica de Catalunya in Manresa (Barcelona), with teaching responsibilities in analog electronics. His current research interest are in Mixed-Signal Testing and Vibration Test Control Systems. Barcons received his Industrial Engineering degree in 1994 from the Universitat Politècnica de Catalunya.Luz Balado received the degree in Industrial Engineering in 1980 from the Universitat Politècnica de Catalunya (UPC) and the Doctor degree in Electronic Engineering in 1986. She is presently Associate Professor at the Electronic Engineering Department of the UPC where teaches Electronics and Electronic Instrumentation and is involved in its Microelectronics and Test research Group. Her main research interests are Design and Test of digital and mixed-signal circuits and defect modeling.Joan Figueras received his Ph.D. degrees from the Universitat Politecnica de Catalunya (UPC), and the University of Michigan in Ann Arbor, Mich. where he was a Fulbright Scholar and worked in the Systems Engineering Laboratory. Currently he is Professor at the the Electronics Engineering Dpt. of the UPC in Barcelona, Spain, with teaching and research responsibilities in the area of electronics and VLSI design. His present research interests include emerging design and test techniques for high performance and low power electronic circuits. He is at present, member of the Editorial Board of the Journal of Electronic Testing (JETTA), Editor of a special issue of the IEEE Transactions on Computer Aided Design, and Chair of the European IEEE Test Technology Technical Council.     

用VB制作李萨如图形动态演示程序

李萨如图形是两个垂直方向简谐运动的合成轨迹,是物理学的主要内容之一,在工程中有很重要的应用。为了深入理解李萨如图形的形成过程,利用VB6.0编程实现动态演示李萨如图形,并提出了一种编制动态演示程序的有效方法。     

单驱动二维扫描光纤探头研制

研制了应用于光学相干层析(OCT)成像的二维扫描光纤探头。该探头利用光纤悬臂的共振特性,结合光纤悬臂的结构不对称性,使光纤悬臂在正交方向具有不同的共振频率。通过对压电双晶片施加接近于上述两种共振频率的混频信号,就能同时激发光纤悬臂两正交方向上的振动,实现光纤悬臂的单驱动二维扫描。扫描采样率对成像质量至关重要,可通过驱动信号的频率选择和图像采集时间的设定来控制。在光纤悬臂固有频率曲线谐振宽度范围内细调驱动信号频率,可形成不同形状因而不同扫描覆盖率的大振幅李萨如轨迹。为实现扫描图像的正确重建,在扫描探头中引入了二维位置敏感探测器,用于扫描轨迹的同步记录。应用所研制的光纤扫描探头于已建立的光学相干层析系统,开展了典型样品的横断面扫描成像实验,在2 frame/s的采样速率获得了初期的实验结果,验证了方案的可行性。     

基于等效鉴相频率的频标比对途径

研究了两个周期性信号之间相位差变化规律和相应的新概念,结合常用的时间频率测量方法,提出了一种新的高精度频标比对方法--基于李沙育图形思想的频标比对方法.这种新方法完全可以用于各种原子频标和高稳定度频率源的测量和比对之中.