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.     

有源电力滤波器在谐波治理中的应用

本文介绍了一个车间变电所内谐波污染的情况,叙述了并联型有源电力滤波器（APF）用于谐波治理的基本原理,并通过实际测量,说明了应用有源电力滤波器进行谐波治理的效果。     

Theoretical design for 120 GHz semiconductor junction circulators: effects of different numbers of terms in the Green's function

A theoretical analysis of the predicted performance and field distributions for semiconductor junction circulators is based on Bosma's Green's function approach which involves a summation of infinite series in the mathematical derivation. The effects are considered of taking a different number of terms in the series, looking at three different circulators centred at 120 GHz. The narrowband semiconductor circulators show a similar effect to the ferrite junction circulator because the field distributions inside the semiconductor discs can be approximated by only considering the dominant modes. However, there is no dominant mode in the broadband circulator and the higher order modes play an important role in the operation of this circulator. In order to obtain a precise representation of the circulation effects inside both narrowband and broadband circulators, at least up to the 6th term, or 18 terms in all, are required to be added in the summation of Green's functions.     

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。     

带分次谐波抑制功能的SVG控制策略研究

本文在无功补偿控制策略的基础上,对其进行适当改进来实现装置的有源滤波功能。由于SVG仅需要对指定次谐波进行补偿,所以需要设计分次谐波提取功能,重点讨论了分次谐波的提取及控制方法:其次,对IIR低通滤波器的NATLAB设计做了说明:最后,对提出的控制策略在控制器SH7058上进行实验,验证了提出的谐波分次补偿功能的正确性。     

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.     

Resistorless dual-mode quadrature sinusoidal oscillator using a single active building block

This paper presents a new realization of resistorless mixed-mode (i.e. both voltage-mode and current-mode) quadrature sinusoidal oscillator using a new active building block (ABB) called the differential voltage current-controlled conveyor transconductance amplifier (DVCCCTA). The proposed oscillator circuit uses a single DVCCCTA, two grounded capacitors (GCs) and does not employ any external linear resistors. The tuning laws for the condition of oscillation (CO) and the frequency of oscillation (FO) are non-interactive; and controlled by separate bias currents. The circuit provides two explicit quadrature current outputs and two quadrature voltage outputs and thus can be classified as a mixed-mode quadrature oscillator. Another notable feature of the proposed circuit is that it can also be used as a biquadratic filter to realize low-pass and band-pass filtering functions simultaneously. Non-ideal analysis of the circuit is provided and PSpice simulation results have been included to verify the workability of the proposed circuit.     

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。     

Current-mode square wave generators based on a single CDTA

This paper proposes two designs for current-mode square wave generators based on a current-differencing transconductance amplifier (CDTA). Both the proposed circuits are compact and employ a single CDTA with only two external passive components. The first circuit has a fixed duty-cycle topology and can generate a symmetrical square wave with variable frequency. The second circuit has a variable duty-cycle design and can operate in a current-controlled dual duty-cycle mode with a single-circuit topology. The proposed generators allow independent control of the operating frequency, output amplitude, and duty cycle by tuning diverse circuit parameters. This paper discusses several previous designs for square wave generators and presents the circuit principles, related governing formulas, and nonideal problems for the proposed circuits. In addition, computer simulations and experimental results, which are consistent with those of the theoretical analyses and confirm the feasibility of the new generators, are presented.