电子经纬仪光电信号处理技术研究

对电子经纬仪光电信号处理关键技术进行了研究,改进了电源开关单元,完善了软件设计,实现了5种操作模式下的各种功能．经过系统的软硬件调试,从硬件上实现了系统所需角度信号的波形变换、脉冲信号的形成和基于FPGA的辨向计数,在此基础上进行软件细分,并分析了此细分方法的误差,测量精度达到2″,读数精度达到1″．     

单圈绝对式光电轴角编码器译码技术

单圈绝对式编码器相比于增量式编码器及传统的绝对式编码器有独特的优势,其关键技术在于译码系统的设计及译码算法的研究。为了提高单圈绝对式编码器集成度、响应速度及精度,设计了译码系统,该系统采用线阵CCD作为码盘图像光电转换装置,并利用FPGA实现电路控制及译码算法。同时提出了新的译码算法,该算法一方面将CCD输出信号二值化后的电平信号高电平计数,判断组合得到粗码信息;另一方面应用质心法进行细分定位,通过计算条纹质心与虚拟中心的偏差得到细分角度值。最后,通过两者结合得到角度信息。基于该系统研制的经纬仪样机精度达到2。     

光电位移信号新型细分方法及系统设计

为提高光电轴角编码器的分辨力,提出一种新型莫尔条纹信号细分方法并建立基于FPGA的光电位移信号倍频系统.根据理想莫尔条纹光电信号的数学模型,利用多倍角正余弦信号的函数性质,将原始莫尔条纹信号推导为n倍频的高阶信号;由幅值细分理论,离线建立基于高阶正余弦信号的高分辨力幅值细分查找表;根据增量式、绝对式光电编码器的不同功能,分别阐述了应用该幅值细分查找表实现编码器高分辨力的倍频技术;同时又指出本文细分方法应用的约束条件.最后,以直径为40mm,分辨率为2500P/R的欧姆龙E6B2-CWZ6C增量式光电编码器为实验对象,在转速范围200~3000rpm的同步电机驱动下,编码器输出波形频率范围约为8.3kHz~125kHz,在基于频率为10kHz的模拟输入信号下,采用本文细分方案设置四倍频设计实验,该系统可以快速将频率增加到原来频率的4倍;同时,基于4倍频原理设计了128倍频实验,并进行实验验证,同样得到该系统可以快速增加到输入频率的128倍.该设计方法及系统与传统细分方法相比较,具有开发周期短、集成度高、模块化、速率快等特点.     

光电经纬仪数字化模型的建立方法及其应用

分析了现在光电经纬仪的研发和检测过程,指出了其不足.基于此本文提出将光电经纬仪划分为有机关联的多个单学科系统模型,通过对几种建模工具的功能的分析,在集成仿真环境中建立其统一的数字化模型,利用模型功能来指导实际光电经纬仪的设计开发和评价其性能指标的方法.初步确定了光电经纬仪系统建模的仿真开发环境和具体的建模仿真的实现方法,实现在设计阶段对光电经纬仪性能的分析评价和工作过程的模拟,对误差的仿真检测实际样机的设计精度指标是否符合要求,为光电经纬仪的误差分析、研制过程提供了理论参考.     

动态精度靶标与光电经纬仪的角度转换及应用

为解决T型架光电经纬仪精度检测难题,通过分析动态精度靶标与光电经纬仪的空间位置关系,计算出动态精度靶标编码器与光电经纬仪的方位和俯仰角度的关系式,分析误差原因并对其进行修正。根据实际检测的需要计算出三者角度变化量之间的关系,建立数学模型,同时根据T型架光电经纬仪的结构特点,设计了偏心方法对其静态精度进行检测,并在检测过程中验证了该数学模型和此偏心检测方法的正确性。     

提高光电轴角编码器细分精度的改进粒子群算法

为提高光电轴角编码器的细分精度及莫尔条纹光电信号的细分倍数,设计了一种基于改进粒子群算法的信号正弦性修正方法。首先,根据莫尔条纹光电信号的数学模型,分析信号质量指标对细分误差的影响;并从编码器的制作、调试、使用等环节出发,指出信号细分误差产生的根本原因;然后,对改进粒子群算法的基本原理和实现步骤做了具体阐述;最后,以21 位光电编码器为实验对象,依据其精码转换的方波信息实现精码信号的自适应采样,同时应用改进算法对采集的编码器原始光电信号进行数据预处理,通过辨识信号模型中的3 个待定参量,直接实现信号等幅性偏差、稳定性偏差、正交性偏差的修正;对算法处理后的莫尔条纹信号进行细分精度检测,实验结果表明:编码器细分误差峰值由19.08降低到2.86,细分精度明显提高。     

光电编码器的应用——细分原理

编码器的光电信号经过电路系统的处理,最终获得代表测量角度的数据代码.电路处理系统中最为关键的是细分技术,它是编码器电路处理系统技术中的专业技术.本文详细介绍了一种细分原理和常用的实现方法,说明了编码器测量基准光栅线数和编码器代码分辨力的关系,分析了细分误差产生的原因.     

一种可变长度光电基准尺

为了实现对非正交轴系激光经纬仪测量系统的快速、准确定向,采用构建新型光电基准尺的方法,提出并研究了一种基于高精度光电位置敏感器件的可变长度光电基准尺构建技术。阐述了非正交轴系激光经纬仪的特点,根据其特点及非正交轴系激光经纬仪测量系统定向的需要,确定了可变长度光电基准尺构建的总体思路,完成了硬件电路设计,构建了可变长度光电基准尺,并标定了两光电位置敏感探测器的空间位姿关系,以实现可变长度基准测量。结果表明,利用该可变长度光电基准尺定向后的测量系统,其相对测量精度优于0.03%,可方便、高精度地实现非正交轴系激光经纬仪测量系统的定向。     

基于幅频特性曲线的光电经纬仪跟踪性能评价

提出了一种测试光电经纬仪幅频特性曲线以及利用该特性曲线评价伺服控制系统跟踪性能的方法。论证了利用频率特性、传递函数、微分（或差分）方程描述同一个系统时所具有的等价关系,给出了利用光电经纬仪幅频特性曲线评价跟踪性能的意义和优势。描述了动态靶标连续调频运动模式下,光电经纬仪跟踪靶标目标时跟踪误差信号的WVD分布。通过分析跟踪误差的WVD分布可知跟踪误差信号为一系列谐波信号的叠加,因目前缺少准确分离该谐波信号的工具和算法,导致无法利用时频分析工具获取幅频特性曲线。因此提出采用间接方式利用线性调频信号测试光电经纬仪幅频特性曲线。最后给出了利用特性曲线评价光电经纬仪跟踪伺服系统性能的方法。     

光电经纬仪中激光测距发射系统设计

论述了在光电经纬仪上应用激光测距装置的重要性,即可实现单台经纬仪确定目标位置.介绍了激光测距的原理及测距方程,针对光电经纬仪中激光测距系统的结构特点,对测距分系统发射系统进行了设计,实现了各种复杂条件下的激光测距.     

基于单片机技术的光电检测研究

目前先电检测技术已经越来越广泛地应用于高科技武器、精密制追等行业中．本文主要介绍一种基于单片机技术的激光检测方法．利用单片机进行激光脉冲信号的调制、控制发射．再结合单片机与光电检测的相关技术设计了检测电路，从而实现利用激先传载信号．进行多路控制．     

New calibration method in electrooptic probing due to wavelengthcontrol and Fabry-Perot resonance

The use of the Fabry-Perot resonance in direct internal electrooptic probing reveals a new calibration method. Substrate resonances modulated by the Pockels effect results in a direct amplitude modulated electrooptic signal. The relation between this signal amplitude and wavelength-derivative of the reflected average probe-beam intensity describes the absolute potential on the device-under-test (DUT). A fibered electrooptic probing system has been developed containing a fiber reinjection probing head. A confocal arrangement optimizes the spatial resolution on the DUT while respecting the Fabry-Perot resonance limit. The direct AM electrooptic probing under wavelength optimization has been demonstrated experimentally by two-dimensional scanning of a monolithic-microwave integrated-circuit section     

A Light Source for Pupil Stimulation

For satisfactory controllable light stimulus to be used for experiments on the human pupillary servomechanism, we designed a system using a potassium dihydrogen phosphate (KDP) electrooptic light modulator and an amplifier capable of giving a suitable high-voltage signal.     

Principles of parametric temporal imaging. I. System configurations

The recently developed process of temporal imaging expands or compresses time waveforms while preserving the shapes of their envelope profiles. A key element in a temporal imaging system is a time lens which imparts a quadratic phase modulation to the waveform being imaged. Several methods, such as electrooptic modulation, can be used to produce the phase modulation. In this paper, we concentrate on the parametric mixing of a signal waveform with a linearly chirped optical pump as the time lens mechanism. We analyze all single-lens system configurations including sum- and difference-frequency mixing schemes with positive and negative group velocity dispersions using temporal ray diagrams as an aid in understanding their operation     

Using an injection-locked diode laser to pump a CW Raman laser

We demonstrate the use of an injection-locked diode laser (792 nm) as the pump source for a continuous-wave (CW) Raman laser with Stokes emission at 1182 nm. Phase modulation of the master signal is imparted to the slave laser output in order to generate an error signal for phase/frequency locking via the Pound-Drever-Hall method. To illustrate the utility of this technique, we achieve the highest pump rate yet observed for a CW Raman laser (>90 times threshold) and compare the data to the existing theory. We also show how current modulation of the slave laser can eliminate the need for an electrooptic modulator in the system altogether     

Monolithic integration of diffractive lenses with LED-arrays forboard-to-board free space optical interconnect

Since optical interconnections can severely reduce problems associated with electrical interconnect technology (including bandwidth limitations, electromagnetic cross talk, signal delay and EMI aspects), the development of suitable electrooptic components is of crucial importance for implementation of optical interconnects in future computer systems. This paper addresses the design, modeling, fabrication as well as experimental assessment of LED-arrays, with diffractive lenses etched into the rear side of the LED-substrate. The suitability of such optical sources for board-to-board optical interconnections will be demonstrated     

Coherence multiplexing using a parallel array of electrooptic modulators and multimode semiconductor lasers

The paper presents a rather new approach of electrooptic modulation of light suitable for coherence multiplexingNtransmission channels. A parallel array ofNelectrooptic multiplexers powered by multimode semiconductor lasers is used for imprinting the signals on light simultaneously. It is shown that the electrooptic multiplexers have to generate optical time delays whose optimal values are ruled by the sequence1/2N cdot delta f, 1/N cdot delta f, 3/2N cdot delta f, etc., wheredelta fis the intermodal separation of the laser longitudinal modes. The performance of the system is discussed in terms of crosstalk, number of possible channels, and signal power. The demonstration of the method is reported in the area of optical communications with the transmission of base-band video signals.     

Transmission line aspects of the design of broad-band electrooptic traveling-wave modulators

This paper proposes a two-layer traveling-wave type electrooptic modulator structure to maximize modulation bandwidth from transmission line aspects. This structure can be designed to satisfy the velocity matching and impedance matching condition simultaneously. A design method for this structure is discussed.     

High-frequency, stripline, multireflection electrooptic beam deflectors

A novel electrooptic (EO) beam deflector has been designed through numerical simulation. This stripline lithium tantalate device has the potential to electrooptically modulate the deflection of an optical pulse at unprecedented frequencies. Velocity matching of the optical pulse to a high-frequency transmission line signal is achieved through reflections of the fast optical pulse. An optimal design criterion is formulated for this device. Deflection capability is estimated to be 8/spl deg/. The device is intended for use in deflection-based optical analog-digital (A/D) conversion.     

An external electrooptic sampling technique based on theFabry-Perot effect

Electrooptic sampling has proved itself as the best technique for the measurement of high-speed electronic signals. This is due to its high bandwidth and noninvasiveness. Standard sampling geometries rely on a rotation of polarization within an electrooptic material and subsequent polarization sensitive detection. In this paper, we present results using a simple technique which relies on Fabry-Perot resonances inside the electrooptic material to produce an amplitude modulation. This simplifies the experiment considerably