Robust tracking servo system considering force disturbance for the optical disk recording system

This paper proposes a new robust tracking servo system for the optical disk recording system with feedforward controller based on the prediction of the tracking error. In optical recording systems, the feedback servo system must suppress the influence of force disturbance and parameter variation. To overcome this problem, this paper designs the robust feedback control system by using coprime factorization and disturbance observer. The detecting signal of the optical disk recording system is only a tracking error. Hence, the feedforward controller of the proposed tracking control system is constructed based on both the "zero-phase-error tracking" control theory and the prediction of the tracking error. The experimental results point out that the proposed tracking servo system has a quick and precise tracking response and keeps the residual tracking error below its tolerance.     

A control method for a nonlinear multivariable system: applicationto interstitial laser hyperthermia

An original adaptive control method is presented for controlling a nonlinear multivariable system. The method, which could be described as a modified quasi-linear approach, involves dividing the source excitation into a series of pulsing rounds and is implemented as a control algorithm on a computer. The theory underlying the method is developed with reference to an application involving temperature control in interstitial laser hyperthermia. In this application, the method is both successful and necessary to achieve optimally uniform elevated temperatures in a ground beef phantom. Apart from variable and parameter definitions, the method is otherwise general and might be useful for controlling a nonlinear system in which no prior exact characterization of the system is possible. Simulations were conducted to assess the effectiveness of the method in systems for which the unit excitation response changes by factors ranging from zero to three over the total period of excitation. In each case the method has proven stable.     

可二次开发的通用视频捕获记录系统

在实际研发的基础上，提出并实现了一种既支持应用软件又支持硬件控制程序的二次开发的通用视频捕获记录系统，详细地阐述了该系统的设计思想及工作流程。     

Fast optical recording media based on semiconductor nanostructures for image recording and processing

Fast optical recording media based on semiconductor nanostructures (CdTe, GaAs) for image recording and processing with a speed to 10⁶ cycle/s (which exceeds the speed of known recording media based on metal-insulator-semiconductor-(liquid crystal) (MIS-LC) structures by two to three orders of magnitude), a photosensitivity of 10^?2V/cm², and a spatial resolution of 5–10 (line pairs)/mm are developed. Operating principles of nanostructures as fast optical recording media and methods for reading images recorded in such media are described. Fast optical processors for recording images in incoherent light based on CdTe crystal nanostructures are implemented. The possibility of their application to fabricate image correlators is shown.     

Modeling and compensation of asymmetry in optical recording

Asymmetry, also known as domain bloom, is a systematic imperfection caused by the writing process in optical or magneto-optical recording. At the reading end of the system, asymmetry causes shifts of adjacent signal transitions in opposite directions. We present a simple nonlinear model for the replay signal in the presence of asymmetry. The model is specified by a single parameter, which is proportional to asymmetry, and its accuracy is demonstrated by application to replay signals from digital video disk drives. Based on the proposed model, a maximum-likelihood sequence detector is designed for replay signals with asymmetry. Simple modifications of the proposed detector lead to significant reductions in complexity, while the attainable performance, evaluated both analytically and through error-rate simulations, is superior to that of conventional techniques.     

Diode lasers for mass market applications: optical recording andprinting

The existence of inexpensive semiconductor diode lasers has led to realization of consumer products in the home entertainment and personal computer industries that are already successful and promise to continue to grow in value. For example, optical recording has proven to be a technology that not only has become a dominant factor in the audio market (CD player), but has found markets as memory peripherals for personal computers and the playback of prerecorded video. In addition, diode laser printers for personal computers will become a large market. Diode-laser-based optical recording and printing systems are reviewed in this paper, as are the properties of the diode lasers that allow these systems to operate so well. Future developments in diode laser technology that will allow enhanced or new systems are also described     

1:1方式带备纤监控的光路检测系统研制

1:1方式带备纤监控的光路检测系统采用ARM核的32位低功耗微处理器作为系统控制核心,系统采用嵌入式μCOS-II2操作系统,可实现主备光纤信道状态同时检测,发现故障时瞬时切换到备用信道,切换时间小于15ms,大大低于ITU-TG.841标准所规定的50ms,确保光路通信畅通无阻,具有实时性强、动态性能良好,运行稳定可...     

Advanced optical disk mastering and its application for extremelyhigh-density magnetic recording

As the demand for recording density becomes stronger, mastering technology becomes more important along with its level of mechanical precision. To visualize such an important technology, the author presents one of the latest examples of optical disk mastering technologies in the application of preembossed magnetic disks. The preembossed magnetic disks have emerged from the integration of two existing technologies: one is magnetic recording technology and the other is optical disk technology. The effect of precision machining for such development is described in detail, along with suggested possible directions of further development in precision mechatronics     

光纤技术的发展及其在光通信中的应用

随着光纤网络的快速增长，光纤技术的发展越来越重要。光子晶体光纤是一种新型光纤，它将会极大地影响光通信的发展，为此对传统光纤进行了分析，对光子晶体光纤的性质和应用前景也进行了讨论和评价。     

光控光开关的发展和应用

综述了光控光开关的发展状况以及它在未来全光网络中的应用 ;分析了几种典型的光控光开关实现方案的结构及原理 ;详细论述了光控光开关在全光网络中的各种应用 ,并通过分析和论述指出光控光开关将在未来的大容量全光网络中发挥关键作用。     

光通信用光接收机技术及其进展

光接收机是光纤通信系统的重要组成部分,它的作用是将由光纤传来的微弱光信号转换为电信号,经放大、处理后恢复原信号.光接收机的性能对整个系统的通信质量有很大的影响.从不同的角度对光接收机进行了分类,进而分析了光接收机技术的最新进展,最后对光接收机技术的发展进行了展望.     

Rayleigh-Sommerfeld and Helmholtz-Kirchhoff integrals: applicationto the scalar and vectorial theory of wave propagation and diffraction

Approximations for known integral solutions of the scalar Helmholtz equation (the Rayleigh-Sommerfeld (RS) integrals of type I and II) are discussed. The validity range of the approximated RS I integral for large, but finite distances from the boundary plane is calculated as a new result. The scalar Kirchhoff boundary conditions leading to a rough approximation of an aperture diffraction problem are inspected, and a new spatial frequency solution in the aperture plane is given. Published measurements and known approximate vectorial boundary values formulated with the Hertz vector are compared with the outcome of the traditional Kirchhoff theory. For the field propagating from light waveguide endfaces into a homogeneous medium, the polarization effects in the far-field are considered by approximating the near-field for weakly guiding fibers with a Hertz vector ansatz. Comparison with measurements shows that the polarization induced asymmetry of the far-field is small in comparison with the experimental uncertainties. Finally, the proper applications for the RS I; II integrals are clarified as opposed to using the scalar or vectorial Helmholtz-Kirchhoff integral     

计数式测力计打印记录系统软硬件设计

讨论了进行疲劳实验装置的软硬件设计,并给出了对夏利车门实验的实验结果。     

Coherent optical QPSK intradyne system: concept and digitalreceiver realization

A receiver concept based on optical quadrature phase-shift keying (QPSK) and a digital realization of synchronous demodulation including phase synchronization is presented. To keep the signal processing bandwidth low a phase diversity receiver, called an intradyne receiver, with an orthogonal electrical demodulation is proposed. Basic principles of the synchronous orthogonal and digital demodulation are described. After the evaluation of the shot noise limit some aspects of the digital phase-locked loop (PLL) are presented. In a 100-Mb/s transmission system a receiver sensitivity of -51.6 dBm has been measured. The loss in relation to the shot noise limit of -66.3 dBm (18 photons/b) is mostly due to the low local laser power and the influence of the receiver input noise     

光盘存储材料

文中评述了光盘存贮介质材料的研究发展情况.目前世界上不可擦型光盘介质材料的大规模研究已基本告一段落.不可擦光盘已成功地用在小型数字式声唱机、电视唱机和随录随放系统中.至于各种可擦型光盘用存贮介质材料,包括态变、相变和磁光型可擦型光盘记录介质,目前正在努力进行广泛的探索试验,可以预计在最近二、三年内将会取得丰硕的研究成果.     

光开关技术发展及应用

人们对光开关的研究巳有二三十年的历史，全光网络的发展，需要高速传输大量数据，光开关越来越受到重视。由于新的光开关技术不断涌现，光开关的规模化和集成化程度不断提高，为此介绍了光开关技术的发展现状及其应用。     

Multimode optical fiber splice loss: Relating system and laboratory measurements

We examine the splice loss occurring along a multimode fiber regenerator span and compare the results to a "standard" laboratory test condition. Large variations in the splice loss sensitivity to transverse offset of a "reference" splice were seen 1) at the ends of 5 different 8.9-km fiber concatenations and 2) at various locations along one 8.9-km path. These data indicate that significant variations in the modal power distribution exist even at the receiver end of a regenerator span. This is explained by the long coupling lengths (long compared to splice spacing) of low loss fibers and the random amount of mode coupling introduced by the concatenation splices. Splice loss measurements made with an "overfilled" launch condition and a 3-turn 20-mm mandrel wrap mode filter (commonly used in fiber loss measurements) accurately approximated the average splice loss sensitivity along the span for offsets less than 4 μm. i.e., losses less than 0.2 dB. For offsets greater than 4 μm, the mandrel wrap mode filter configuration yields a pessimistic estimate, but is within 30 percent of the average "system" loss for most cases of interest. This demonstrates the usefulness of the mode filter in establishing splice measurement conditions that yield results representative of those seen in a regenerator span.     

图象智能检测报警记录系统的技术设计

提出了图象灰度的亮度加权平均和位置加权平均的一种新的图象变化识别技术，依此原理并把电视技术与计算机技术相结合，设计研制了图象智能检测报警记录系统，介绍了系统的组成及技术原理。     

全光网络技术及其发展前景

随着光纤通信的飞速发展,光纤通信有向全光网发展的趋势.文中介绍了全光网的概念、优点及一些关键技术,展望了未来光通信的发展前景.     

光纤通信技术现状与发展

目前，光纤通信正向高速、宽带和超长距离方向发展．文章介绍了光纤通信技术的发展现状，并对光纤通信的发展趋势进行了展望．