基于PIC的激光吉他设计

激光光源作为新一代的能量光源,以其极好的聚光特性,在应用中有着不可比拟的优势。本文介绍了一种基于PIC单片机的激光吉他设计方案,提出了系统构架,阐述了软硬件的实现方式。该设计方案以激光代替传统物质弦,在具备强大娱乐性的同时,也极大便利了操作,提高了演奏准确性。     

基于SoPC的捷联系统硬件平台的设计

为了提高激光陀螺捷联系统的硬件平台集成度并减小其功耗,满足微小型导航系统的要求,在基于Xilinx的Virtex-4 FPGA芯片上,通过SoPC方法设计新一代硬件平台。该硬件平台使用FPGA内嵌的PowerPC405硬核处理器作为功能控制与运算中心,并在FPGA逻辑中设计功能全面的IP核来实现数据采集、数字滤波、串口通信和部分导航解算。从而在保证较高的运算速度和精度的同时,达到了预期的效果。     

基于MATLAB的无人飞行器两点交会定位算法研究

空间飞行器现有定位算法采用单点测距测角,定位误差高达上百米。该文提出了空间两点交会定位方法,该方法可有效提高定位精度,并通过MATLAB进行了算法实现,最终编写了定位软件。     

太赫兹技术在室内无线通信中的应用

该文通过对太赫兹通信相关器件的总结和相关信道特性的分析,调研了近年来国内外相关实验的结果,对重点实验结果做了着重描述,总结出了未来室内无线通信可能的发展方向和亟待解决的问题。太赫兹波段是介于毫米波与远红外的电磁辐射频段。室内无线局域网的高数据率传输要求通信系统运行于更高的频率以获得更大的带宽。太赫兹频率范围未受军事管制,可实现Gbit/s数据率,并且太赫兹频域不像光频受环境噪声干扰那么严重。全固态室温太赫兹器件的研究为太赫兹无线通信系统奠定了基础。已探明适于未来太赫兹室内通信系统运行的大气窗口。基于飞秒激光门控光导天线的太赫兹通信链路实现了太赫兹波载波音频信号的调制和解调。     

设计素描观察能力的培养

观察能力的培养是设计素描训练的基本任务之一。设计素描应以传统素描的观察方法为基础,并更加强调用理性的、逻辑的、创造性的思维方法来观察、认识、分析物象。设计素描的观察方法必须经过由感性到理性的循序渐进的过程。文章通过:1、整体对比的观察。2、宏观与微观的观察。3、不同视点与角度的观察,三个依次渐进的过程来分析设计素描的观察方法。通过分析,希望在设计素描教学中把观察能力的培养提升到一个相当重要的位置。只有这样才能为日后设计专业学习打下良好的设计创意思维基础。     

The evaluation of speckle contrast with variable speckle generator

Abstract— While laser projection has many advantages, there is a problem with speckle patterns generated as a result of interference of the laser beam and results in bad effects to observers. In 2010, a variable speckle generator, which produces an angular shift of incident light to the screen and generates variable speckle patterns, was suggested. In this study, the performance of a variable speckle generator by using a volume phase holographic beam shaper and scanning mirror was investigated in detail by evaluating both the objective and subjective speckle contrast. The morphology of the speckle pattern was also investigated when the variable speckle generator was activated. With a scanning VPH beam shaper, the objective speckle was effectively reduced because each point of the VPH beam shaper generated different speckle patterns and coherency among each pattern disappeared by using the scan process. On the other hand, subjective speckle was also dramatically reduced by changing the incident angle on the screen, which resulted in generating variable subjective speckle. It was also shown that the speckle reduction rate by using a variable speckle generator did not depend on the coherent length of a laser by evaluating the normalized speckle contrast against the angular shift on the screen.     

A closed-form derivation of self and multi-user interference for time-reversed UWB communications

Multipath degradation is a significant consideration for all wireless communication systems. A time-reversed UWB system harnesses the multipath channel to achieve temporal and spatial focusing through signal pre-filtering at the transmitter side. In cases where the RMS delay spread of a channel is larger than a user’s transmitted pulse separation, inter-pulse, -frame, and -symbol interference may occur. Of even more concern is multi-user interference, which significantly reduces system performance. This paper presents closed-form expressions for self and multi-user interference for a UWB system utilizing a time-reversed approach. The influence of user multiplexing codes is taken to account through incorporation of a ‘separation probability’, which characterizes a family of hopping sequences. The standardized IEEE 802.15.3a channel model is applied, and the derived performances are compared with that of a simulated time hopped time-reversed UWB system.     

环形激光陀螺测试技术的研究与设计

针对某环形激光陀螺传感器的总体输出误差特点,应用Allan方差法完成了对RLG频域输出误差的建模评估,包括陀螺的随机游走误差、零偏稳定性误差,以及马尔可夫噪声误差等,建立了温度误差零偏补偿模型。在陀螺测试过程中,采用了转台交差逆转的方法,尝试将零偏衰减中的常值漂移和线性漂移部分自动补消,结果表明可以改善传统的RLG转台测试法的测试精度。     

基于功率MOSFET的激光器外触发系统研制

采用功率MOSFET及其驱动器和光纤收发器件,研究了激光触发开关脉冲功率源控制技术中的快上升沿(≤5ns)触发信号产生、驱动、传输及光纤隔离、高耐压脉冲变压器使用等关键技术。给出了激光器外触发控制电路的设计及测试结果,并对其应用特点进行了分析和讨论。     

Laser marking system for light guide panel using design of experiment and web-based prototyping

A light guide panel (LGP) is an element of the liquid crystal display (LCD) back light unit (BLU), which is used for display devices. In this study, the laser marking process is applied to the fabrication of light guide panels as the new fabrication process. In order to obtain a light guide panel which has high luminance and uniformity, four principal parameters such as power, scanning speed, ratio of line gap, and number of line were selected. A web-based design tool was developed to generate patterns of light guide panel via the network, and the tool may assist the designer to develop various prototype patterns. Topcon-BM7 was used for luminance measurement of each specimen with 100 mm×100 mm area. By Taguchi method, optimized levels of each parameter were found, and luminance of 3523 cd/cm² and uniformity of 92% were achieved using the laser machined BLU.