无线通信系统维特比译码的FPGA仿真验证

在设计宽带无线通信系统的基带平台中,采用一种基于FPGA仿真工具Active HDL和目前广泛用于数字信号处理、数值分析等的实用软件Matlab相结合的方法,通过实现(2,1,7)卷积编码的全并行维特比软判决译码的FPGA设计仿真和算法验证,提出一种利用Matlab进行测试向量的生成和验证,以简化仿真测试序列的手工输入,提高FPGA设计进程和保证代码质量的方法。     

Integrated linear giga-ohm resistance using current scaling

Integrated grounded resistors of very large value are essential circuit elements for the design of compact filters with very low cut-off frequencies. A typical application of such filters is the rejection of DC voltages in amplifier circuits especially in physiological recording systems exhibiting electrode offset and low-frequency drift. In this letter, the implementation of a giga-ohm resistance is presented using a conventional fixed-gain OTA and a cascade of weak-inversion current scalers. The circuit yields a short design time, small power and area consumption as well as high linearity. A test circuit having an area of 0.011 mm² integrated in 0.35 μm CMOS is presented which yields a 41 Hz cut-off frequency, 1 V input range and less than −52 dB THD when connected to an integrated 1 pF capacitor, making it a suitable solution for the rejection of mains interference and offset in wearable biomedical applications.     

Design and Performance Analysis of Emulator for Standard Conformance Test of Active RFID

An active radio frequency identification (RFID) system has the advantages of a long identification distance and a good identification rate, overcoming passive RFID drawbacks. Therefore, interest in the development of active RFID systems has been gradually increasing in areas of harbor logistics and national defense. However, some identification failures between active RFID systems developed under the same standards have been reported, presumably due to a lack of development of accurate evaluation methods and test equipment. We present a realization of the hardware and software of an emulator to evaluate the standard conformance of an active RFID system in a fully anechoic chamber. The performance levels of the designed emulator are analyzed using Matlab/Simulink simulations, and the applicability of the emulator is verified by evaluating the standard conformance of a real active RFID tag. Finally, we propose a new evaluation method by incorporating a self‐running test mode environment into the RFID tags to reduce testing time and increase testing accuracy. The application of the suggested method to actual tags improves measurement uncertainty by 0.56 dB over that obtained using existing methods.     

High-performance active polyphase filter design for digital TV tuner

This paper presents the polyphase filter design for the tuner of DTV front-end system. The polyphase filter is designed with an active circuit to improve the chip performance. Most of passive capacitor and resistor components are replaced with MOS transistors. The proposed method not only can reduce the chip area but also gain the signal level. For the prototyping implementation, the current channel bands in Taiwan are referred, which the frequency range is from 530 to 602 MHz for DTV programs. In experiments, the polyphase filter can achieve 85 dB for the image rejection in the center frequency. The main signal can be gained about 2-5 dB without using extra amplifier. The chip size is about 0.09 mm², and the average power dissipation is about 15 mW, when the chip technology employed TSMC 0.35 μm CMOS process. The proposed chip outperforms with less area and higher gain.     

主动拒止武器系统的概述

主动拒止技术武器属于“威慑”类,而不是“惩治”或“致残”类非致命武器,该武器利用热敏效应有效的阻止人员敌对行动,而不会有什么间接影响。尤其要强调的是,主动拒止系统武器不会使人失明,也不会致癌,它将成为未来战场上革命性的武器。文中介绍了针对人员的非致命性主动拒止武器系统的研究背景、工作机理以及目前的发展状况,最后对主动拒止武器系统的未来发展方向进行了讨论。     

Identification of rod dynamics under influence of Active Magnetic Bearing

The purpose of this paper is to apply the wavelet transform algorithm to identify the magnetic damping and magnetic stiffness coefficients of the drive rod with which a set of 4-pole Active Magnetic Bearing (AMB) is equipped. By taking advantage of time–frequency analysis feature, the ridge curve of rod free response after wavelet transformation can be extracted to find the natural frequency of the rod/AMB system. In other words, due to the influence of magnetized field by the AMB, the stiffness of the rod dynamics is not linear any more and can be estimated from the curve of the amplitude versus frequency by wavelet transformation. On the other hand, the nonlinear damping coefficients can be estimated from the derivative of amplitude versus amplitude by wavelet transformation of rod free vibration. It is found that the nonlinear magnetic damping coefficients are up to 2nd-order in polynomial and the stiffness coefficient is mainly of 3rd-order respectively. In addition, the identified 2nd-order damping coefficient is negative and hence implies that under specific rod displacement and speed, the dynamic of the rod/AMB system in axial direction is unstable.     

基于ASP的实验室开放管理系统的设计与实现

基于ASP语言设计了实验室开放管理系统,通过网络实现了教师对实验课程的发布、修改,以及学生对实验的预习、预约。     

基于Web Services的网络测量系统的研究与实现

在分析现有网络测量系统的基础上。文章实现了一个基于Web Services技术的网络测量系统，具有良好的可扩展性和可伸缩性．并且针对IPv6协议的出现开发了相应的测量模块，可以同时测量IPv4网络和IPv6网络的性能。     

网上考试应用系统

介绍了在Ｉｎｔｅｒｎｅｔ环境下利用活动服务器页面（ＡＳＰ）技术,设计一套网上考试系统的实施方案和技术分析,具体介绍了在整个系统的实施中所需要的数据库结构、系统组成以及网页的设计。     

并联型有源电力滤波器的SVPWM控制技术研究

针对有源滤波器常规滞环、三角载波控制时,开关频率波动大,响应慢的缺点,引入了空间电压矢量算法。在K步时,假定K+1步,APF的补偿电流完全跟踪上了谐波指令电流,再根据APF离散的数学模型及空间电压矢量调制模块,确定第K+1步的开关管驱动信号,以达到快速补偿谐波电流的目的。仿真实验表明,基于SVPWM控制的有源滤波器具有开关频率固定,动态响应快,补偿精度高的优点。